Pilot/Controller Glossary

Pilot/Controller Glossary10/12/17

PCG−1

PILOT/CONTROLLER

GLOSSARY

PURPOSE

a. This Glossary was compiled to promote a common understanding of the terms used in the Air Traffic

Control system. It includes those terms which are intended for pilot/controller communications. Those terms

most frequently used in pilot/controller communications are printed in bold italics. The definitions are primarily

defined in an operational sense applicable to both users and operators of the National Airspace System. Use of

the Glossary will preclude any misunderstandings concerning the system’s design, function, and purpose.

b. Because of the international nature of flying, terms used in the Lexicon, published by the International

Civil Aviation Organization (ICAO), are included when they differ from FAA definitions. These terms are

followed by “[ICAO].” For the reader’s convenience, there are also cross references to related terms in other parts

of the Glossary and to other documents, such as the Code of Federal Regulations (CFR) and the Aeronautical

Information Manual (AIM).

c. This Glossary will be revised, as necessary, to maintain a common understanding of the system.

EXPLANATION OF CHANGES

d. Terms Added:

RUNWAY CONDITION CODES (RWYCC)

RUNWAY CONDITION REPORT (RWYCR)

SPECIAL AIR TRAFFIC RULES (SATR)

SPECIAL FLIGHT RULES AREA (SFRA)

WEATHER RECONNAISSANCE AREA (WRA)

e. Terms Modified:

BRAKING ACTION (GOOD, FAIR, POOR, OR NIL)

BRAKING ACTION ADVISORIES

ENHANCED FLIGHT VISION SYSTEM (EFVS)

ESTABLISHED

PRECIPITATION RADAR WEATHER DESCRIPTIONS

RADAR IDENTIFICATION

f. Editorial/format changes were made where necessary. Revision bars were not used due to the insignificant

nature of the changes.

Pilot/Controller Glossary

10/12/17

PCG A−1

AAI−

(See ARRIVAL AIRCRAFT INTERVAL.)

AAR−

(See AIRPORT ARRIVAL RATE.)

ABBREVIATED IFR FLIGHT PLANS− An

authorization by ATC requiring pilots to submit only

that information needed for the purpose of ATC. It

includes only a small portion of the usual IFR flight

plan information. In certain instances, this may be

only aircraft identification, location, and pilot

request. Other information may be requested if

needed by ATC for separation/control purposes. It is

frequently used by aircraft which are airborne and

desire an instrument approach or by aircraft which are

on the ground and desire a climb to VFR-on-top.

(See VFR-ON-TOP.)

(Refer to AIM.)

ABEAM− An aircraft is “abeam” a fix, point, or

object when that fix, point, or object is approximately

90 degrees to the right or left of the aircraft track.

Abeam indicates a general position rather than a

precise point.

ABORT− To terminate a preplanned aircraft

maneuver; e.g., an aborted takeoff.

ACC [ICAO]−

(See ICAO term AREA CONTROL CENTER.)

ACCELERATE-STOP DISTANCE AVAILABLE−

The runway plus stopway length declared available

and suitable for the acceleration and deceleration of

an airplane aborting a takeoff.

ACCELERATE-STOP DISTANCE AVAILABLE

[ICAO]− The length of the take-off run available plus

the length of the stopway if provided.

ACDO−

(See AIR CARRIER DISTRICT OFFICE.)

ACKNOWLEDGE− Let me know that you have

received and understood this message.

ACL−

(See AIRCRAFT LIST.)

ACLS−

(See AUTOMATIC CARRIER LANDING

SYSTEM.)

ACLT−

(See ACTUAL CALCULATED LANDING TIME.)

ACROBATIC FLIGHT− An intentional maneuver

involving an abrupt change in an aircraft’s attitude, an

abnormal attitude, or abnormal acceleration not

necessary for normal flight.

(See ICAO term ACROBATIC FLIGHT.)

(Refer to 14 CFR Part 91.)

ACROBATIC FLIGHT [ICAO]− Maneuvers inten-

tionally performed by an aircraft involving an abrupt

change in its attitude, an abnormal attitude, or an

abnormal variation in speed.

ACTIVE RUNWAY−

(See RUNWAY IN USE/ACTIVE RUNWAY/DUTY

RUNWAY.)

ACTUAL CALCULATED LANDING TIME−

ACLT is a flight’s frozen calculated landing time. An

actual time determined at freeze calculated landing

time (FCLT) or meter list display interval (MLDI) for

the adapted vertex for each arrival aircraft based upon

runway configuration, airport acceptance rate, airport

arrival delay period, and other metered arrival

aircraft. This time is either the vertex time of arrival

(VTA) of the aircraft or the tentative calculated

landing time (TCLT)/ACLT of the previous aircraft

plus the arrival aircraft interval (AAI), whichever is

later. This time will not be updated in response to the

aircraft’s progress.

ACTUAL NAVIGATION PERFORMANCE

(ANP)−

(See REQUIRED NAVIGATION

PERFORMANCE.)

ADDITIONAL SERVICES− Advisory information

provided by ATC which includes but is not limited to

the following:

a. Traffic advisories.

b. Vectors, when requested by the pilot, to assist

aircraft receiving traffic advisories to avoid observed

traffic.

c. Altitude deviation information of 300 feet or

more from an assigned altitude as observed on a

verified (reading correctly) automatic altitude

readout (Mode C).

d. Advisories that traffic is no longer a factor.

Pilot/Controller Glossary 10/12/17

PCG A−2

e. Weather and chaff information.

f. Weather assistance.

g. Bird activity information.

h. Holding pattern surveillance. Additional ser-

vices are provided to the extent possible contingent

only upon the controller’s capability to fit them into

the performance of higher priority duties and on the

basis of limitations of the radar, volume of traffic,

frequency congestion, and controller workload. The

controller has complete discretion for determining if

he/she is able to provide or continue to provide a

service in a particular case. The controller’s reason

not to provide or continue to provide a service in a

particular case is not subject to question by the pilot

and need not be made known to him/her.

(See TRAFFIC ADVISORIES.)

(Refer to AIM.)

ADF−

(See AUTOMATIC DIRECTION FINDER.)

ADIZ−

(See AIR DEFENSE IDENTIFICATION ZONE.)

ADLY−

(See ARRIVAL DELAY.)

ADMINISTRATOR− The Federal Aviation Admin-

istrator or any person to whom he/she has delegated

his/her authority in the matter concerned.

ADR−

(See AIRPORT DEPARTURE RATE.)

ADS [ICAO]−

(See ICAO term AUTOMATIC DEPENDENT

SURVEILLANCE.)

ADS−B−

(See AUTOMATIC DEPENDENT

SURVEILLANCE−BROADCAST.)

ADS−C−

(See AUTOMATIC DEPENDENT

SURVEILLANCE−CONTRACT.)

ADVISE INTENTIONS− Tell me what you plan to

do.

ADVISORY− Advice and information provided to

assist pilots in the safe conduct of flight and aircraft

movement.

(See ADVISORY SERVICE.)

ADVISORY FREQUENCY− The appropriate fre-

quency to be used for Airport Advisory Service.

(See LOCAL AIRPORT ADVISORY.)

(See UNICOM.)

(Refer to ADVISORY CIRCULAR NO. 90-42.)

(Refer to AIM.)

ADVISORY SERVICE− Advice and information

provided by a facility to assist pilots in the safe

conduct of flight and aircraft movement.

(See ADDITIONAL SERVICES.)

(See LOCAL AIRPORT ADVISORY.)

(See RADAR ADVISORY.)

(See SAFETY ALERT.)

(See TRAFFIC ADVISORIES.)

(Refer to AIM.)

AERIAL REFUELING− A procedure used by the

military to transfer fuel from one aircraft to another

during flight.

(Refer to VFR/IFR Wall Planning Charts.)

AERODROME− A defined area on land or water

(including any buildings, installations and equip-

ment) intended to be used either wholly or in part for

the arrival, departure, and movement of aircraft.

AERODROME BEACON [ICAO]− Aeronautical

beacon used to indicate the location of an aerodrome

from the air.

AERODROME CONTROL SERVICE [ICAO]− Air

traffic control service for aerodrome traffic.

AERODROME CONTROL TOWER [ICAO]− A

unit established to provide air traffic control service

to aerodrome traffic.

AERODROME ELEVATION [ICAO]− The eleva-

tion of the highest point of the landing area.

AERODROME TRAFFIC CIRCUIT [ICAO]− The

specified path to be flown by aircraft operating in the

vicinity of an aerodrome.

AERONAUTICAL BEACON− A visual NAVAID

displaying flashes of white and/or colored light to

indicate the location of an airport, a heliport, a

landmark, a certain point of a Federal airway in

mountainous terrain, or an obstruction.

(See AIRPORT ROTATING BEACON.)

(Refer to AIM.)

AERONAUTICAL CHART− A map used in air

navigation containing all or part of the following:

topographic features, hazards and obstructions,

Pilot/Controller Glossary

10/12/17

PCG A−3

navigation aids, navigation routes, designated

airspace, and airports. Commonly used aeronautical

charts are:

a. Sectional Aeronautical Charts (1:500,000)−

Designed for visual navigation of slow or medium

speed aircraft. Topographic information on these

charts features the portrayal of relief and a judicious

selection of visual check points for VFR flight.

Aeronautical information includes visual and radio

aids to navigation, airports, controlled airspace,

restricted areas, obstructions, and related data.

b. VFR Terminal Area Charts (1:250,000)−

Depict Class B airspace which provides for the

control or segregation of all the aircraft within Class

B airspace. The chart depicts topographic informa-

tion and aeronautical information which includes

visual and radio aids to navigation, airports,

controlled airspace, restricted areas, obstructions,

and related data.

c. En Route Low Altitude Charts− Provide

aeronautical information for en route instrument

navigation (IFR) in the low altitude stratum.

Information includes the portrayal of airways, limits

of controlled airspace, position identification and

frequencies of radio aids, selected airports, minimum

en route and minimum obstruction clearance

altitudes, airway distances, reporting points, re-

stricted areas, and related data. Area charts, which are

a part of this series, furnish terminal data at a larger

scale in congested areas.

d. En Route High Altitude Charts− Provide

aeronautical information for en route instrument

navigation (IFR) in the high altitude stratum.

Information includes the portrayal of jet routes,

identification and frequencies of radio aids, selected

airports, distances, time zones, special use airspace,

and related information.

e. Instrument Approach Procedure (IAP) Charts−

Portray the aeronautical data which is required to

execute an instrument approach to an airport. These

charts depict the procedures, including all related

data, and the airport diagram. Each procedure is

designated for use with a specific type of electronic

navigation system including NDB, TACAN, VOR,

ILS RNAV and GLS. These charts are identified by

the type of navigational aid(s)/equipment required to

provide final approach guidance.

f. Instrument Departure Procedure (DP) Charts−

Designed to expedite clearance delivery and to

facilitate transition between takeoff and en route

operations. Each DP is presented as a separate chart

and may serve a single airport or more than one

airport in a given geographical location.

g. Standard Terminal Arrival (STAR) Charts−

Designed to expedite air traffic control arrival

procedures and to facilitate transition between en

route and instrument approach operations. Each

STAR procedure is presented as a separate chart and

may serve a single airport or more than one airport in

a given geographical location.

h. Airport Taxi Charts− Designed to expedite the

efficient and safe flow of ground traffic at an airport.

These charts are identified by the official airport

name; e.g., Ronald Reagan Washington National

Airport.

(See ICAO term AERONAUTICAL CHART.)

AERONAUTICAL CHART [ICAO]− A representa-

tion of a portion of the earth, its culture and relief,

specifically designated to meet the requirements of

air navigation.

AERONAUTICAL INFORMATION MANUAL

(AIM)− A primary FAA publication whose purpose

is to instruct airmen about operating in the National

Airspace System of the U.S. It provides basic flight

information, ATC Procedures and general instruc-

tional information concerning health, medical facts,

factors affecting flight safety, accident and hazard

reporting, and types of aeronautical charts and their

use.

AERONAUTICAL INFORMATION PUBLICA-

TION (AIP) [ICAO]− A publication issued by or with

the authority of a State and containing aeronautical

information of a lasting character essential to air

navigation.

(See CHART SUPPLEMENT U.S.)

AFFIRMATIVE− Yes.

AFIS−

(See AUTOMATIC FLIGHT INFORMATION

SERVICE − ALASKA FSSs ONLY.)

AFP−

(See AIRSPACE FLOW PROGRAM.)

AIM−

(See AERONAUTICAL INFORMATION

MANUAL.)

Pilot/Controller Glossary 10/12/17

PCG A−4

AIP [ICAO]−

(See ICAO term AERONAUTICAL

INFORMATION PUBLICATION.)

AIR CARRIER DISTRICT OFFICE− An FAA field

office serving an assigned geographical area, staffed

with Flight Standards personnel serving the aviation

industry and the general public on matters related to

the certification and operation of scheduled air

carriers and other large aircraft operations.

AIR DEFENSE EMERGENCY− A military emer-

gency condition declared by a designated authority.

This condition exists when an attack upon the

continental U.S., Alaska, Canada, or U.S. installa-

tions in Greenland by hostile aircraft or missiles is

considered probable, is imminent, or is taking place.

(Refer to AIM.)

AIR DEFENSE IDENTIFICATION ZONE (ADIZ)−

The area of airspace over land or water, extending

upward from the surface, within which the ready

identification, the location, and the control of aircraft

are required in the interest of national security.

a. Domestic Air Defense Identification Zone. An

ADIZ within the United States along an international

boundary of the United States.

b. Coastal Air Defense Identification Zone. An

ADIZ over the coastal waters of the United States.

c. Distant Early Warning Identification Zone

(DEWIZ). An ADIZ over the coastal waters of the

State of Alaska.

d. Land−Based Air Defense Identification Zone.

An ADIZ over U.S. metropolitan areas, which is

activated and deactivated as needed, with dimen-

sions, activation dates and other relevant information

disseminated via NOTAM.

Note: ADIZ locations and operating and flight plan

requirements for civil aircraft operations are

specified in 14 CFR Part 99.

(Refer to AIM.)

AIR NAVIGATION FACILITY− Any facility used

in, available for use in, or designed for use in, aid of

air navigation, including landing areas, lights, any

apparatus or equipment for disseminating weather

information, for signaling, for radio-directional

finding, or for radio or other electrical communica-

tion, and any other structure or mechanism having a

similar purpose for guiding or controlling flight in the

air or the landing and takeoff of aircraft.

(See NAVIGATIONAL AID.)

AIR ROUTE SURVEILLANCE RADAR− Air route

traffic control center (ARTCC) radar used primarily

to detect and display an aircraft’s position while en

route between terminal areas. The ARSR enables

controllers to provide radar air traffic control service

when aircraft are within the ARSR coverage. In some

instances, ARSR may enable an ARTCC to provide

terminal radar services similar to but usually more

limited than those provided by a radar approach

control.

AIR ROUTE TRAFFIC CONTROL CENTER

(ARTCC)− A facility established to provide air traffic

control service to aircraft operating on IFR flight

plans within controlled airspace and principally

during the en route phase of flight. When equipment

capabilities and controller workload permit, certain

advisory/assistance services may be provided to VFR

aircraft.

(See EN ROUTE AIR TRAFFIC CONTROL

SERVICES.)

(Refer to AIM.)

AIR TAXI− Used to describe a helicopter/VTOL

aircraft movement conducted above the surface but

normally not above 100 feet AGL. The aircraft may

proceed either via hover taxi or flight at speeds more

than 20 knots. The pilot is solely responsible for

selecting a safe airspeed/altitude for the operation

being conducted.

(See HOVER TAXI.)

(Refer to AIM.)

AIR TRAFFIC− Aircraft operating in the air or on an

airport surface, exclusive of loading ramps and

parking areas.

(See ICAO term AIR TRAFFIC.)

AIR TRAFFIC [ICAO]− All aircraft in flight or

operating on the maneuvering area of an aerodrome.

AIR TRAFFIC CLEARANCE− An authorization by

air traffic control for the purpose of preventing

collision between known aircraft, for an aircraft to

proceed under specified traffic conditions within

controlled airspace. The pilot-in-command of an

aircraft may not deviate from the provisions of a

visual flight rules (VFR) or instrument flight rules

(IFR) air traffic clearance except in an emergency or

unless an amended clearance has been obtained.

Additionally, the pilot may request a different

clearance from that which has been issued by air

traffic control (ATC) if information available to the

pilot makes another course of action more practicable

Pilot/Controller Glossary

10/12/17

PCG A−5

or if aircraft equipment limitations or company

procedures forbid compliance with the clearance

issued. Pilots may also request clarification or

amendment, as appropriate, any time a clearance is

not fully understood, or considered unacceptable

because of safety of flight. Controllers should, in

such instances and to the extent of operational

practicality and safety, honor the pilot’s request.

14 CFR Part 91.3(a) states: “The pilot in command

of an aircraft is directly responsible for, and is the

final authority as to, the operation of that aircraft.”

THE PILOT IS RESPONSIBLE TO REQUEST AN

AMENDED CLEARANCE if ATC issues a

clearance that would cause a pilot to deviate from a

rule or regulation, or in the pilot’s opinion, would

place the aircraft in jeopardy.

(See ATC INSTRUCTIONS.)

(See ICAO term AIR TRAFFIC CONTROL

CLEARANCE.)

AIR TRAFFIC CONTROL− A service operated by

appropriate authority to promote the safe, orderly and

expeditious flow of air traffic.

(See ICAO term AIR TRAFFIC CONTROL

SERVICE.)

AIR TRAFFIC CONTROL CLEARANCE [ICAO]−

Authorization for an aircraft to proceed under

conditions specified by an air traffic control unit.

Note 1: For convenience, the term air traffic control

clearance is frequently abbreviated to clearance

when used in appropriate contexts.

Note 2: The abbreviated term clearance may be

prefixed by the words taxi, takeoff, departure, en

route, approach or landing to indicate the particular

portion of flight to which the air traffic control clear-

ance relates.

AIR TRAFFIC CONTROL SERVICE−

(See AIR TRAFFIC CONTROL.)

AIR TRAFFIC CONTROL SERVICE [ICAO]− A

service provided for the purpose of:

a. Preventing collisions:

1. Between aircraft; and

2. On the maneuvering area between aircraft

and obstructions.

b. Expediting and maintaining an orderly flow of

air traffic.

AIR TRAFFIC CONTROL SPECIALIST− A person

authorized to provide air traffic control service.

(See AIR TRAFFIC CONTROL.)

(See FLIGHT SERVICE STATION.)

(See ICAO term CONTROLLER.)

AIR TRAFFIC CONTROL SYSTEM COMMAND

CENTER (ATCSCC)− An Air Traffic Tactical

Operations facility responsible for monitoring and

managing the flow of air traffic throughout the NAS,

producing a safe, orderly, and expeditious flow of

traffic while minimizing delays. The following

functions are located at the ATCSCC:

a. Central Altitude Reservation Function

(CARF). Responsible for coordinating, planning,

and approving special user requirements under the

Altitude Reservation (ALTRV) concept.

(See ALTITUDE RESERVATION.)

b. Airport Reservation Office (ARO). Monitors

the operation and allocation of reservations for

unscheduled operations at airports designated by the

Administrator as High Density Airports. These

airports are generally known as slot controlled

airports. The ARO allocates reservations on a first

come, first served basis determined by the time the

request is received at the ARO.

(Refer to 14 CFR Part 93.)

(See CHART SUPPLEMENT U.S.)

c. U.S. Notice to Airmen (NOTAM) Office.

Responsible for collecting, maintaining, and distrib-

uting NOTAMs for the U.S. civilian and military, as

well as international aviation communities.

(See NOTICE TO AIRMEN.)

d. Weather Unit. Monitor all aspects of weather

for the U.S. that might affect aviation including cloud

cover, visibility, winds, precipitation, thunderstorms,

icing, turbulence, and more. Provide forecasts based

on observations and on discussions with meteorolo-

gists from various National Weather Service offices,

FAA facilities, airlines, and private weather services.

AIR TRAFFIC SERVICE− A generic term meaning:

a. Flight Information Service.

b. Alerting Service.

c. Air Traffic Advisory Service.

d. Air Traffic Control Service:

1. Area Control Service,

2. Approach Control Service, or

3. Airport Control Service.

AIR TRAFFIC SERVICE (ATS) ROUTES − The

term “ATS Route” is a generic term that includes

Pilot/Controller Glossary 10/12/17

PCG A−6

“VOR Federal airways,” “colored Federal airways,”

“jet routes,” and “RNAV routes.” The term “ATS

route” does not replace these more familiar route

names, but serves only as an overall title when listing

the types of routes that comprise the United States

route structure.

AIRBORNE− An aircraft is considered airborne

when all parts of the aircraft are off the ground.

AIRBORNE DELAY− Amount of delay to be

encountered in airborne holding.

AIRCRAFT− Device(s) that are used or intended to

be used for flight in the air, and when used in air traffic

control terminology, may include the flight crew.

(See ICAO term AIRCRAFT.)

AIRCRAFT [ICAO]− Any machine that can derive

support in the atmosphere from the reactions of the air

other than the reactions of the air against the earth’s

surface.

AIRCRAFT APPROACH CATEGORY− A

grouping of aircraft based on a speed of 1.3 times the

stall speed in the landing configuration at maximum

gross landing weight. An aircraft must fit in only one

category. If it is necessary to maneuver at speeds in

excess of the upper limit of a speed range for a

category, the minimums for the category for that

speed must be used. For example, an aircraft which

falls in Category A, but is circling to land at a speed

in excess of 91 knots, must use the approach

Category B minimums when circling to land. The

categories are as follows:

a. Category A− Speed less than 91 knots.

b. Category B− Speed 91 knots or more but less

than 121 knots.

c. Category C− Speed 121 knots or more but less

than 141 knots.

d. Category D− Speed 141 knots or more but less

than 166 knots.

e. Category E− Speed 166 knots or more.

(Refer to 14 CFR Part 97.)

AIRCRAFT CLASSES− For the purposes of Wake

Turbulence Separation Minima, ATC classifies

aircraft as Super, Heavy, Large, and Small as follows:

a. Super. The Airbus A-380-800 (A388) and the

Antonov An-225 (A225) are classified as super.

b. Heavy− Aircraft capable of takeoff weights of

300,000 pounds or more whether or not they are

operating at this weight during a particular phase of

flight.

c. Large− Aircraft of more than 41,000 pounds,

maximum certificated takeoff weight, up to but not

including 300,000 pounds.

d. Small− Aircraft of 41,000 pounds or less

maximum certificated takeoff weight.

(Refer to AIM.)

AIRCRAFT CONFLICT− Predicted conflict, within

EDST of two aircraft, or between aircraft and

airspace. A Red alert is used for conflicts when the

predicted minimum separation is 5 nautical miles or

less. A Yellow alert is used when the predicted

minimum separation is between 5 and approximately

12 nautical miles. A Blue alert is used for conflicts

between an aircraft and predefined airspace.

(See EN ROUTE DECISION SUPPORT

TOOL

AIRCRAFT LIST (ACL)− A view available with

EDST that lists aircraft currently in or predicted to be

in a particular sector’s airspace. The view contains

textual flight data information in line format and may

be sorted into various orders based on the specific

needs of the sector team.

(See EN ROUTE DECISION SUPPORT

TOOL

AIRCRAFT SURGE LAUNCH AND

RECOVERY− Procedures used at USAF bases to

provide increased launch and recovery rates in

instrument flight rules conditions. ASLAR is based

on:

a. Reduced separation between aircraft which is

based on time or distance. Standard arrival separation

applies between participants including multiple

flights until the DRAG point. The DRAG point is a

published location on an ASLAR approach where

aircraft landing second in a formation slows to a

predetermined airspeed. The DRAG point is the

reference point at which MARSA applies as

expanding elements effect separation within a flight

or between subsequent participating flights.

b. ASLAR procedures shall be covered in a Letter

of Agreement between the responsible USAF

military ATC facility and the concerned Federal

Aviation Administration facility. Initial Approach

Fix spacing requirements are normally addressed as

a minimum.

Pilot/Controller Glossary

10/12/17

PCG A−7

AIRMEN’S METEOROLOGICAL

INFORMATION−

(See AIRMET.)

AIRMET− In-flight weather advisories issued only

to amend the area forecast concerning weather

phenomena which are of operational interest to all

aircraft and potentially hazardous to aircraft having

limited capability because of lack of equipment,

instrumentation, or pilot qualifications. AIRMETs

concern weather of less severity than that covered by

SIGMETs or Convective SIGMETs. AIRMETs

cover moderate icing, moderate turbulence, sustained

winds of 30 knots or more at the surface, widespread

areas of ceilings less than 1,000 feet and/or visibility

less than 3 miles, and extensive mountain

obscurement.

(See AWW.)

(See CONVECTIVE SIGMET.)

(See CWA.)

(See SIGMET.)

(Refer to AIM.)

AIRPORT− An area on land or water that is used or

intended to be used for the landing and takeoff of

aircraft and includes its buildings and facilities, if

any.

AIRPORT ADVISORY AREA− The area within ten

miles of an airport without a control tower or where

the tower is not in operation, and on which a Flight

Service Station is located.

(See LOCAL AIRPORT ADVISORY.)

(Refer to AIM.)

AIRPORT ARRIVAL RATE (AAR)− A dynamic

input parameter specifying the number of arriving

aircraft which an airport or airspace can accept from

the ARTCC per hour. The AAR is used to calculate

the desired interval between successive arrival

aircraft.

AIRPORT DEPARTURE RATE (ADR)− A dynamic

parameter specifying the number of aircraft which

can depart an airport and the airspace can accept per

hour.

AIRPORT ELEVATION− The highest point of an

airport’s usable runways measured in feet from mean

sea level.

(See TOUCHDOWN ZONE ELEVATION.)

(See ICAO term AERODROME ELEVATION.)

AIRPORT LIGHTING− Various lighting aids that

may be installed on an airport. Types of airport

lighting include:

a. Approach Light System (ALS)− An airport

lighting facility which provides visual guidance to

landing aircraft by radiating light beams in a

directional pattern by which the pilot aligns the

aircraft with the extended centerline of the runway on

his/her final approach for landing. Condenser-

Discharge Sequential Flashing Lights/Sequenced

Flashing Lights may be installed in conjunction with

the ALS at some airports. Types of Approach Light

Systems are:

1. ALSF-1− Approach Light System with

Sequenced Flashing Lights in ILS Cat-I configura-

tion.

2. ALSF-2− Approach Light System with

Sequenced Flashing Lights in ILS Cat-II configura-

tion. The ALSF-2 may operate as an SSALR when

weather conditions permit.

3. SSALF− Simplified Short Approach Light

System with Sequenced Flashing Lights.

4. SSALR− Simplified Short Approach Light

System with Runway Alignment Indicator Lights.

5. MALSF− Medium Intensity Approach Light

System with Sequenced Flashing Lights.

6. MALSR− Medium Intensity Approach Light

System with Runway Alignment Indicator Lights.

7. RLLS− Runway Lead-in Light System

Consists of one or more series of flashing lights

installed at or near ground level that provides positive

visual guidance along an approach path, either

curving or straight, where special problems exist with

hazardous terrain, obstructions, or noise abatement

procedures.

8. RAIL− Runway Alignment Indicator Lights−

Sequenced Flashing Lights which are installed only

in combination with other light systems.

9. ODALS− Omnidirectional Approach Light-

ing System consists of seven omnidirectional

flashing lights located in the approach area of a

nonprecision runway. Five lights are located on the

runway centerline extended with the first light

located 300 feet from the threshold and extending at

equal intervals up to 1,500 feet from the threshold.

The other two lights are located, one on each side of

the runway threshold, at a lateral distance of 40 feet

from the runway edge, or 75 feet from the runway

Pilot/Controller Glossary 10/12/17

PCG A−8

edge when installed on a runway equipped with a

VASI.

(Refer to FAA Order JO 6850.2, VISUAL

GUIDANCE LIGHTING SYSTEMS.)

b. Runway Lights/Runway Edge Lights− Lights

having a prescribed angle of emission used to define

the lateral limits of a runway. Runway lights are

uniformly spaced at intervals of approximately 200

feet, and the intensity may be controlled or preset.

c. Touchdown Zone Lighting− Two rows of

transverse light bars located symmetrically about the

runway centerline normally at 100 foot intervals. The

basic system extends 3,000 feet along the runway.

d. Runway Centerline Lighting− Flush centerline

lights spaced at 50-foot intervals beginning 75 feet

from the landing threshold and extending to within 75

feet of the opposite end of the runway.

e. Threshold Lights− Fixed green lights arranged

symmetrically left and right of the runway centerline,

identifying the runway threshold.

f. Runway End Identifier Lights (REIL)− Two

synchronized flashing lights, one on each side of the

runway threshold, which provide rapid and positive

identification of the approach end of a particular

runway.

g. Visual Approach Slope Indicator (VASI)− An

airport lighting facility providing vertical visual

approach slope guidance to aircraft during approach

to landing by radiating a directional pattern of high

intensity red and white focused light beams which

indicate to the pilot that he/she is “on path” if he/she

sees red/white, “above path” if white/white, and

“below path” if red/red. Some airports serving large

aircraft have three-bar VASIs which provide two

visual glide paths to the same runway.

h. Precision Approach Path Indicator (PAPI)− An

airport lighting facility, similar to VASI, providing

vertical approach slope guidance to aircraft during

approach to landing. PAPIs consist of a single row of

either two or four lights, normally installed on the left

side of the runway, and have an effective visual range

of about 5 miles during the day and up to 20 miles at

night. PAPIs radiate a directional pattern of high

intensity red and white focused light beams which

indicate that the pilot is “on path” if the pilot sees an

equal number of white lights and red lights, with

white to the left of the red; “above path” if the pilot

sees more white than red lights; and “below path” if

the pilot sees more red than white lights.

i. Boundary Lights− Lights defining the perimeter

of an airport or landing area.

(Refer to AIM.)

AIRPORT MARKING AIDS− Markings used on

runway and taxiway surfaces to identify a specific

runway, a runway threshold, a centerline, a hold line,

etc. A runway should be marked in accordance with

its present usage such as:

a. Visual.

b. Nonprecision instrument.

c. Precision instrument.

(Refer to AIM.)

AIRPORT REFERENCE POINT (ARP)− The

approximate geometric center of all usable runway

surfaces.

AIRPORT RESERVATION OFFICE− Office

responsible for monitoring the operation of slot

controlled airports. It receives and processes requests

for unscheduled operations at slot controlled airports.

AIRPORT ROTATING BEACON− A visual

NAVAID operated at many airports. At civil airports,

alternating white and green flashes indicate the

location of the airport. At military airports, the

beacons flash alternately white and green, but are

differentiated from civil beacons by dualpeaked (two

quick) white flashes between the green flashes.

(See INSTRUMENT FLIGHT RULES.)

(See SPECIAL VFR OPERATIONS.)

(See ICAO term AERODROME BEACON.)

(Refer to AIM.)

AIRPORT STREAM FILTER (ASF)− An on/off

filter that allows the conflict notification function to

be inhibited for arrival streams into single or multiple

airports to prevent nuisance alerts.

AIRPORT SURFACE DETECTION EQUIPMENT

(ASDE)− Surveillance equipment specifically de-

signed to detect aircraft, vehicular traffic, and other

objects, on the surface of an airport, and to present the

image on a tower display. Used to augment visual

observation by tower personnel of aircraft and/or

vehicular movements on runways and taxiways.

There are three ASDE systems deployed in the NAS:

a. ASDE−3− a Surface Movement Radar.

b. ASDE−X− a system that uses an X−band

Surface Movement Radar, multilateration, and

ADS−B.

c. Airport Surface Surveillance Capability

(ASSC)− A system that uses Surface Movement

Radar, multilateration, and ADS−B.

Pilot/Controller Glossary

10/12/17

PCG A−9

AIRPORT SURVEILLANCE RADAR− Approach

control radar used to detect and display an aircraft’s

position in the terminal area. ASR provides range and

azimuth information but does not provide elevation

data. Coverage of the ASR can extend up to 60 miles.

AIRPORT TAXI CHARTS−

(See AERONAUTICAL CHART.)

AIRPORT TRAFFIC CONTROL SERVICE− A

service provided by a control tower for aircraft

operating on the movement area and in the vicinity of

an airport.

(See MOVEMENT AREA.)

(See TOWER.)

(See ICAO term AERODROME CONTROL

SERVICE.)

AIRPORT TRAFFIC CONTROL TOWER−

(See TOWER.)

AIRSPACE CONFLICT− Predicted conflict of an

aircraft and active Special Activity Airspace (SAA).

AIRSPACE FLOW PROGRAM (AFP)− AFP is a

Traffic Management (TM) process administered by

the Air Traffic Control System Command Center

(ATCSCC) where aircraft are assigned an Expect

Departure Clearance Time (EDCT) in order to

manage capacity and demand for a specific area of the

National Airspace System (NAS). The purpose of the

program is to mitigate the effects of en route

constraints. It is a flexible program and may be

implemented in various forms depending upon the

needs of the air traffic system.

AIRSPACE HIERARCHY− Within the airspace

classes, there is a hierarchy and, in the event of an

overlap of airspace: Class A preempts Class B, Class

B preempts Class C, Class C preempts Class D, Class

D preempts Class E, and Class E preempts Class G.

AIRSPEED− The speed of an aircraft relative to its

surrounding air mass. The unqualified term

“airspeed” means one of the following:

a. Indicated Airspeed− The speed shown on the

aircraft airspeed indicator. This is the speed used in

pilot/controller communications under the general

term “airspeed.”

(Refer to 14 CFR Part 1.)

b. True Airspeed− The airspeed of an aircraft

relative to undisturbed air. Used primarily in flight

planning and en route portion of flight. When used in

pilot/controller communications, it is referred to as

“true airspeed” and not shortened to “airspeed.”

AIRSTART− The starting of an aircraft engine while

the aircraft is airborne, preceded by engine shutdown

during training flights or by actual engine failure.

AIRWAY− A Class E airspace area established in the

form of a corridor, the centerline of which is defined

by radio navigational aids.

(See FEDERAL AIRWAYS.)

(See ICAO term AIRWAY.)

(Refer to 14 CFR Part 71.)

(Refer to AIM.)

AIRWAY [ICAO]− A control area or portion thereof

established in the form of corridor equipped with

radio navigational aids.

AIRWAY BEACON− Used to mark airway segments

in remote mountain areas. The light flashes Morse

Code to identify the beacon site.

(Refer to AIM.)

AIT−

(See AUTOMATED INFORMATION

TRANSFER.)

ALERFA (Alert Phase) [ICAO]− A situation wherein

apprehension exists as to the safety of an aircraft and

its occupants.

ALERT− A notification to a position that there

is an aircraft-to-aircraft or aircraft-to-airspace

conflict, as detected by Automated Problem

Detection (APD).

ALERT AREA−

(See SPECIAL USE AIRSPACE.)

ALERT NOTICE (ALNOT)− A request originated

by a flight service station (FSS) or an air route traffic

control center (ARTCC) for an extensive commu-

nication search for overdue, unreported, or missing

aircraft.

ALERTING SERVICE− A service provided to notify

appropriate organizations regarding aircraft in need

of search and rescue aid and assist such organizations

as required.

ALNOT−

(See ALERT NOTICE.)

ALONG−TRACK DISTANCE (ATD)− The hori-

zontal distance between the aircraft’s current position

and a fix measured by an area navigation system that

is not subject to slant range errors.

Pilot/Controller Glossary 10/12/17

PCG A−10

ALPHANUMERIC DISPLAY− Letters and numer-

als used to show identification, altitude, beacon code,

and other information concerning a target on a radar

display.

(See AUTOMATED RADAR TERMINAL

SYSTEMS.)

ALTERNATE AERODROME [ICAO]− An aero-

drome to which an aircraft may proceed when it

becomes either impossible or inadvisable to proceed

to or to land at the aerodrome of intended landing.

Note: The aerodrome from which a flight departs

may also be an en-route or a destination alternate

aerodrome for the flight.

ALTERNATE AIRPORT− An airport at which an

aircraft may land if a landing at the intended airport

becomes inadvisable.

(See ICAO term ALTERNATE AERODROME.)

ALTIMETER SETTING− The barometric pressure

reading used to adjust a pressure altimeter for

variations in existing atmospheric pressure or to the

standard altimeter setting (29.92).

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

ALTITUDE− The height of a level, point, or object

measured in feet Above Ground Level (AGL) or from

Mean Sea Level (MSL).

(See FLIGHT LEVEL.)

a. MSL Altitude− Altitude expressed in feet

measured from mean sea level.

b. AGL Altitude− Altitude expressed in feet

measured above ground level.

c. Indicated Altitude− The altitude as shown by an

altimeter. On a pressure or barometric altimeter it is

altitude as shown uncorrected for instrument error

and uncompensated for variation from standard

atmospheric conditions.

(See ICAO term ALTITUDE.)

ALTITUDE [ICAO]− The vertical distance of a level,

a point or an object considered as a point, measured

from mean sea level (MSL).

ALTITUDE READOUT− An aircraft’s altitude,

transmitted via the Mode C transponder feature, that

is visually displayed in 100-foot increments on a

radar scope having readout capability.

(See ALPHANUMERIC DISPLAY.)

(See AUTOMATED RADAR TERMINAL

SYSTEMS.)

(Refer to AIM.)

ALTITUDE RESERVATION (ALTRV)− Airspace

utilization under prescribed conditions normally

employed for the mass movement of aircraft or other

special user requirements which cannot otherwise be

accomplished. ALTRVs are approved by the

appropriate FAA facility.

(See AIR TRAFFIC CONTROL SYSTEM

COMMAND CENTER.)

ALTITUDE RESTRICTION− An altitude or alti-

tudes, stated in the order flown, which are to be

maintained until reaching a specific point or time.

Altitude restrictions may be issued by ATC due to

traffic, terrain, or other airspace considerations.

ALTITUDE RESTRICTIONS ARE CANCELED−

Adherence to previously imposed altitude restric-

tions is no longer required during a climb or descent.

ALTRV−

(See ALTITUDE RESERVATION.)

AMVER−

(See AUTOMATED MUTUAL-ASSISTANCE

VESSEL RESCUE SYSTEM.)

APB−

(See AUTOMATED PROBLEM DETECTION

BOUNDARY.)

APD−

(See AUTOMATED PROBLEM DETECTION.)

APDIA−

(See AUTOMATED PROBLEM DETECTION

INHIBITED AREA.)

APPROACH CLEARANCE− Authorization by

ATC for a pilot to conduct an instrument approach.

The type of instrument approach for which a

clearance and other pertinent information is provided

in the approach clearance when required.

(See CLEARED APPROACH.)

(See INSTRUMENT APPROACH

PROCEDURE.)

(Refer to AIM.)

(Refer to 14 CFR Part 91.)

Pilot/Controller Glossary

10/12/17

PCG A−11

APPROACH CONTROL FACILITY− A terminal

ATC facility that provides approach control service in

a terminal area.

(See APPROACH CONTROL SERVICE.)

(See RADAR APPROACH CONTROL

FACILITY.)

APPROACH CONTROL SERVICE− Air traffic

control service provided by an approach control

facility for arriving and departing VFR/IFR aircraft

and, on occasion, en route aircraft. At some airports

not served by an approach control facility, the

ARTCC provides limited approach control service.

(See ICAO term APPROACH CONTROL

SERVICE.)

(Refer to AIM.)

APPROACH CONTROL SERVICE [ICAO]− Air

traffic control service for arriving or departing

controlled flights.

APPROACH GATE− An imaginary point used

within ATC as a basis for vectoring aircraft to the

final approach course. The gate will be established

along the final approach course 1 mile from the final

approach fix on the side away from the airport and

will be no closer than 5 miles from the landing

threshold.

APPROACH HOLD AREA− The locations on

taxiways in the approach or departure areas of a

runway designated to protect landing or departing

aircraft. These locations are identified by signs and

markings.

APPROACH LIGHT SYSTEM−

(See AIRPORT LIGHTING.)

APPROACH SEQUENCE− The order in which

aircraft are positioned while on approach or awaiting

approach clearance.

(See LANDING SEQUENCE.)

(See ICAO term APPROACH SEQUENCE.)

APPROACH SEQUENCE [ICAO]− The order in

which two or more aircraft are cleared to approach to

land at the aerodrome.

APPROACH SPEED− The recommended speed

contained in aircraft manuals used by pilots when

making an approach to landing. This speed will vary

for different segments of an approach as well as for

aircraft weight and configuration.

APPROACH WITH VERTICAL GUIDANCE

(APV)– A term used to describe RNAV approach

procedures that provide lateral and vertical guidance

but do not meet the requirements to be considered a

precision approach.

APPROPRIATE ATS AUTHORITY [ICAO]− The

relevant authority designated by the State responsible

for providing air traffic services in the airspace

concerned. In the United States, the “appropriate ATS

authority” is the Program Director for Air Traffic

Planning and Procedures, ATP-1.

APPROPRIATE AUTHORITY−

a. Regarding flight over the high seas: the relevant

authority is the State of Registry.

b. Regarding flight over other than the high seas:

the relevant authority is the State having sovereignty

over the territory being overflown.

APPROPRIATE OBSTACLE CLEARANCE

MINIMUM ALTITUDE− Any of the following:

(See MINIMUM EN ROUTE IFR ALTITUDE.)

(See MINIMUM IFR ALTITUDE.)

(See MINIMUM OBSTRUCTION CLEARANCE

ALTITUDE.)

(See MINIMUM VECTORING ALTITUDE.)

APPROPRIATE TERRAIN CLEARANCE

MINIMUM ALTITUDE− Any of the following:

(See MINIMUM EN ROUTE IFR ALTITUDE.)

(See MINIMUM IFR ALTITUDE.)

(See MINIMUM OBSTRUCTION CLEARANCE

ALTITUDE.)

(See MINIMUM VECTORING ALTITUDE.)

APRON− A defined area on an airport or heliport

intended to accommodate aircraft for purposes of

loading or unloading passengers or cargo, refueling,

parking, or maintenance. With regard to seaplanes, a

ramp is used for access to the apron from the water.

(See ICAO term APRON.)

APRON [ICAO]− A defined area, on a land

aerodrome, intended to accommodate aircraft for

purposes of loading or unloading passengers, mail or

cargo, refueling, parking or maintenance.

ARC− The track over the ground of an aircraft flying

at a constant distance from a navigational aid by

reference to distance measuring equipment (DME).

AREA CONTROL CENTER [ICAO]− An air traffic

control facility primarily responsible for ATC

services being provided IFR aircraft during the en

Pilot/Controller Glossary 10/12/17

PCG A−12

route phase of flight. The U.S. equivalent facility is

an air route traffic control center (ARTCC).

AREA NAVIGATION (RNAV)− A method of

navigation which permits aircraft operation on any

desired flight path within the coverage of ground− or

space−based navigation aids or within the limits of

the capability of self-contained aids, or a combination

of these.

Note: Area navigation includes

performance−based navigation as well as other

operations that do not meet the definition of

performance−based navigation.

AREA NAVIGATION (RNAV) APPROACH

CONFIGURATION:

a. STANDARD T− An RNAV approach whose

design allows direct flight to any one of three initial

approach fixes (IAF) and eliminates the need for

procedure turns. The standard design is to align the

procedure on the extended centerline with the missed

approach point (MAP) at the runway threshold, the

final approach fix (FAF), and the initial approach/

intermediate fix (IAF/IF). The other two IAFs will be

established perpendicular to the IF.

b. MODIFIED T− An RNAV approach design for

single or multiple runways where terrain or

operational constraints do not allow for the standard

T. The “T” may be modified by increasing or

decreasing the angle from the corner IAF(s) to the IF

or by eliminating one or both corner IAFs.

c. STANDARD I− An RNAV approach design for

a single runway with both corner IAFs eliminated.

Course reversal or radar vectoring may be required at

busy terminals with multiple runways.

d. TERMINAL ARRIVAL AREA (TAA)− The

TAA is controlled airspace established in conjunction

with the Standard or Modified T and I RNAV

approach configurations. In the standard TAA, there

are three areas: straight-in, left base, and right base.

The arc boundaries of the three areas of the TAA are

published portions of the approach and allow aircraft

to transition from the en route structure direct to the

nearest IAF. TAAs will also eliminate or reduce

feeder routes, departure extensions, and procedure

turns or course reversal.

1. STRAIGHT-IN AREA− A 30NM arc

centered on the IF bounded by a straight line

extending through the IF perpendicular to the

intermediate course.

2. LEFT BASE AREA− A 30NM arc centered

on the right corner IAF. The area shares a boundary

with the straight-in area except that it extends out for

30NM from the IAF and is bounded on the other side

by a line extending from the IF through the FAF to the

arc.

3. RIGHT BASE AREA− A 30NM arc centered

on the left corner IAF. The area shares a boundary

with the straight-in area except that it extends out for

30NM from the IAF and is bounded on the other side

by a line extending from the IF through the FAF to the

arc.

AREA NAVIGATION (RNAV) GLOBAL

POSITIONING SYSTEM (GPS) PRECISION

RUNWAY MONITORING (PRM) APPROACH–

A GPS approach, which requires vertical guidance,

used in lieu of an ILS PRM approach to conduct

approaches to parallel runways whose extended

centerlines are separated by less than 4,300 feet and

at least 3,000 feet, where simultaneous close parallel

approaches are permitted. Also used in lieu of an ILS

PRM and/or LDA PRM approach to conduct

Simultaneous Offset Instrument Approach (SOIA)

operations.

ARINC− An acronym for Aeronautical Radio, Inc.,

a corporation largely owned by a group of airlines.

ARINC is licensed by the FCC as an aeronautical

station and contracted by the FAA to provide

communications support for air traffic control and

meteorological services in portions of international

airspace.

ARMY AVIATION FLIGHT INFORMATION

BULLETIN− A bulletin that provides air operation

data covering Army, National Guard, and Army

Reserve aviation activities.

ARO−

(See AIRPORT RESERVATION OFFICE.)

ARRESTING SYSTEM− A safety device consisting

of two major components, namely, engaging or

catching devices and energy absorption devices for

the purpose of arresting both tailhook and/or

nontailhook-equipped aircraft. It is used to prevent

aircraft from overrunning runways when the aircraft

cannot be stopped after landing or during aborted

takeoff. Arresting systems have various names; e.g.,

arresting gear, hook device, wire barrier cable.

(See ABORT.)

(Refer to AIM.)

Pilot/Controller Glossary

10/12/17

PCG A−13

ARRIVAL AIRCRAFT INTERVAL− An internally

generated program in hundredths of minutes based

upon the AAR. AAI is the desired optimum interval

between successive arrival aircraft over the vertex.

ARRIVAL CENTER− The ARTCC having jurisdic-

tion for the impacted airport.

ARRIVAL DELAY− A parameter which specifies a

period of time in which no aircraft will be metered for

arrival at the specified airport.

ARRIVAL SECTOR− An operational control sector

containing one or more meter fixes.

ARRIVAL SECTOR ADVISORY LIST− An

ordered list of data on arrivals displayed at the

PVD/MDM of the sector which controls the meter

fix.

ARRIVAL SEQUENCING PROGRAM− The auto-

mated program designed to assist in sequencing

aircraft destined for the same airport.

ARRIVAL TIME− The time an aircraft touches down

on arrival.

ARSR−

(See AIR ROUTE SURVEILLANCE RADAR.)

ARTCC−

(See AIR ROUTE TRAFFIC CONTROL

CENTER.)

ARTS−

(See AUTOMATED RADAR TERMINAL

SYSTEMS.)

ASDA−

(See ACCELERATE-STOP DISTANCE

AVAILABLE.)

ASDA [ICAO]−

(See ICAO Term ACCELERATE-STOP

DISTANCE AVAILABLE.)

ASDE−

(See AIRPORT SURFACE DETECTION

EQUIPMENT.)

ASF−

(See AIRPORT STREAM FILTER.)

ASLAR−

(See AIRCRAFT SURGE LAUNCH AND

RECOVERY.)

ASP−

(See ARRIVAL SEQUENCING PROGRAM.)

ASR−

(See AIRPORT SURVEILLANCE RADAR.)

ASR APPROACH−

(See SURVEILLANCE APPROACH.)

ASSOCIATED− A radar target displaying a data

block with flight identification and altitude

information.

(See UNASSOCIATED.)

ATC−

(See AIR TRAFFIC CONTROL.)

ATC ADVISES− Used to prefix a message of

noncontrol information when it is relayed to an

aircraft by other than an air traffic controller.

(See ADVISORY.)

ATC ASSIGNED AIRSPACE− Airspace of defined

vertical/lateral limits, assigned by ATC, for the

purpose of providing air traffic segregation between

the specified activities being conducted within the

assigned airspace and other IFR air traffic.

(See SPECIAL USE AIRSPACE.)

ATC CLEARANCE−

(See AIR TRAFFIC CLEARANCE.)

ATC CLEARS− Used to prefix an ATC clearance

when it is relayed to an aircraft by other than an air

traffic controller.

ATC INSTRUCTIONS− Directives issued by air

traffic control for the purpose of requiring a pilot to

take specific actions; e.g., “Turn left heading two five

zero,” “Go around,” “Clear the runway.”

(Refer to 14 CFR Part 91.)

ATC PREFERRED ROUTE NOTIFICATION−

EDST notification to the appropriate controller of the

need to determine if an ATC preferred route needs to

be applied, based on destination airport.

(See ROUTE ACTION NOTIFICATION.)

(See EN ROUTE DECISION SUPPORT TOOL.)

ATC PREFERRED ROUTES− Preferred routes that

are not automatically applied by Host.

ATC REQUESTS− Used to prefix an ATC request

when it is relayed to an aircraft by other than an air

traffic controller.

ATC SECURITY SERVICES− Communications

and security tracking provided by an ATC facility in

support of the DHS, the DOD, or other Federal

security elements in the interest of national security.

Such security services are only applicable within

Pilot/Controller Glossary 10/12/17

PCG A−14

designated areas. ATC security services do not

include ATC basic radar services or flight following.

ATC SECURITY SERVICES POSITION− The

position responsible for providing ATC security

services as defined. This position does not provide

ATC, IFR separation, or VFR flight following

services, but is responsible for providing security

services in an area comprising airspace assigned to

one or more ATC operating sectors. This position

may be combined with control positions.

ATC SECURITY TRACKING− The continuous

tracking of aircraft movement by an ATC facility in

support of the DHS, the DOD, or other security

elements for national security using radar (i.e., radar

tracking) or other means (e.g., manual tracking)

without providing basic radar services (including

traffic advisories) or other ATC services not defined

in this section.

ATS SURVEILLANCE SERVICE [ICAO]– A term

used to indicate a service provided directly by means

of an ATS surveillance system.

ATC SURVEILLANCE SOURCE– Used by ATC

for establishing identification, control and separation

using a target depicted on an air traffic control

facility’s video display that has met the relevant

safety standards for operational use and received

from one, or a combination, of the following

surveillance sources:

a. Radar (See RADAR.)

b. ADS-B (See AUTOMATIC DEPENDENT

SURVEILLANCE−BROADCAST.)

c. WAM (See WIDE AREA MULTILATERATION.)

(See INTERROGATOR.)

(See TRANSPONDER.)

(See ICAO term RADAR.)

(Refer to AIM.)

ATS SURVEILLANCE SYSTEM [ICAO]– A

generic term meaning variously, ADS−B, PSR, SSR

or any comparable ground−based system that enables

the identification of aircraft.

Note: A comparable ground−based system is one

that has been demonstrated, by comparative

assessment or other methodology, to have a level

of safety and performance equal to or better than

monopulse SSR.

ATCAA−

(See ATC ASSIGNED AIRSPACE.)

ATCRBS−

(See RADAR.)

ATCSCC−

(See AIR TRAFFIC CONTROL SYSTEM

COMMAND CENTER.)

ATCT−

(See TOWER.)

ATD−

(See ALONG−TRACK DISTANCE.)

ATIS−

(See AUTOMATIC TERMINAL INFORMATION

SERVICE.)

ATIS [ICAO]−

(See ICAO Term AUTOMATIC TERMINAL

INFORMATION SERVICE.)

ATS ROUTE [ICAO]− A specified route designed for

channeling the flow of traffic as necessary for the

provision of air traffic services.

Note: The term “ATS Route” is used to mean

variously, airway, advisory route, controlled or

uncontrolled route, arrival or departure, etc.

ATTENTION ALL USERS PAGE (AAUP)- The

AAUP provides the pilot with additional information

relative to conducting a specific operation, for

example, PRM approaches and RNAV departures.

AUTOLAND APPROACH−An autoland system

aids by providing control of aircraft systems during

a precision instrument approach to at least decision

altitude and possibly all the way to touchdown, as

well as in some cases, through the landing rollout.

The autoland system is a sub-system of the autopilot

system from which control surface management

occurs. The aircraft autopilot sends instructions to the

autoland system and monitors the autoland system

performance and integrity during its execution.

AUTOMATED INFORMATION TRANSFER

(AIT)− A precoordinated process, specifically

defined in facility directives, during which a transfer

of altitude control and/or radar identification is

accomplished without verbal coordination between

controllers using information communicated in a full

data block.

AUTOMATED MUTUAL-ASSISTANCE VESSEL

RESCUE SYSTEM− A facility which can deliver, in

a matter of minutes, a surface picture (SURPIC) of

vessels in the area of a potential or actual search and

Pilot/Controller Glossary

10/12/17

PCG A−15

rescue incident, including their predicted positions

and their characteristics.

(See FAA Order JO 7110.65, Para 10−6−4,

INFLIGHT CONTINGENCIES.)

AUTOMATED PROBLEM DETECTION (APD)−

An Automation Processing capability that compares

trajectories in order to predict conflicts.

AUTOMATED PROBLEM DETECTION

BOUNDARY (APB)− The adapted distance beyond

a facilities boundary defining the airspace within

which EDST performs conflict detection.

(See EN ROUTE DECISION SUPPORT TOOL.)

AUTOMATED PROBLEM DETECTION INHIB-

ITED AREA (APDIA)− Airspace surrounding a

terminal area within which APD is inhibited for all

flights within that airspace.

AUTOMATED RADAR TERMINAL SYSTEMS

(ARTS)− A generic term for several tracking systems

included in the Terminal Automation Systems (TAS).

ARTS plus a suffix roman numeral denotes a major

modification to that system.

a. ARTS IIIA. The Radar Tracking and Beacon

Tracking Level (RT&BTL) of the modular, program-

mable automated radar terminal system. ARTS IIIA

detects, tracks, and predicts primary as well as

secondary radar-derived aircraft targets. This more

sophisticated computer-driven system upgrades the

existing ARTS III system by providing improved

tracking, continuous data recording, and fail-soft

capabilities.

b. Common ARTS. Includes ARTS IIE, ARTS

IIIE; and ARTS IIIE with ACD (see DTAS) which

combines functionalities of the previous ARTS

systems.

AUTOMATED WEATHER SYSTEM− Any of the

automated weather sensor platforms that collect

weather data at airports and disseminate the weather

information via radio and/or landline. The systems

currently consist of the Automated Surface Observ-

ing System (ASOS), Automated Weather Sensor

System (AWSS) and Automated Weather Observa-

tion System (AWOS).

AUTOMATED UNICOM− Provides completely

automated weather, radio check capability and airport

advisory information on an Automated UNICOM

system. These systems offer a variety of features,

typically selectable by microphone clicks, on the

UNICOM frequency. Availability will be published

in the Chart Supplement U.S. and approach charts.

AUTOMATIC ALTITUDE REPORT−

(See ALTITUDE READOUT.)

AUTOMATIC ALTITUDE REPORTING− That

function of a transponder which responds to Mode C

interrogations by transmitting the aircraft’s altitude

in 100-foot increments.

AUTOMATIC CARRIER LANDING SYSTEM−

U.S. Navy final approach equipment consisting of

precision tracking radar coupled to a computer data

link to provide continuous information to the aircraft,

monitoring capability to the pilot, and a backup

approach system.

AUTOMATIC DEPENDENT SURVEILLANCE

(ADS) [ICAO]− A surveillance technique in which

aircraft automatically provide, via a data link, data

derived from on−board navigation and position

fixing systems, including aircraft identification, four

dimensional position and additional data as

appropriate.

AUTOMATIC DEPENDENT SURVEILLANCE−

BROADCAST (ADS-B)− A surveillance system in

which an aircraft or vehicle to be detected is fitted

with cooperative equipment in the form of a data link

transmitter. The aircraft or vehicle periodically

broadcasts its GPS−derived position and other

information such as velocity over the data link, which

is received by a ground−based transmitter/receiver

(transceiver) for processing and display at an air

traffic control facility.

(See GLOBAL POSITIONING SYSTEM.)

(See GROUND−BASED TRANSCEIVER.)

AUTOMATIC DEPENDENT SURVEILLANCE−

CONTRACT (ADS−C)− A data link position

reporting system, controlled by a ground station, that

establishes contracts with an aircraft’s avionics that

occur automatically whenever specific events occur,

or specific time intervals are reached.

AUTOMATIC DEPENDENT SURVEILLANCE-

REBROADCAST (ADS-R)− A datalink translation

function of the ADS−B ground system required to

accommodate the two separate operating frequencies

(978 MHz and 1090 MHz). The ADS−B system

receives the ADS−B messages transmitted on one

frequency and ADS−R translates and reformats the

information for rebroadcast and use on the other

frequency. This allows ADS−B In equipped aircraft

Pilot/Controller Glossary 10/12/17

PCG A−16

to see nearby ADS−B Out traffic regardless of the

operating link of the other aircraft. Aircraft operating

on the same ADS−B frequency exchange information

directly and do not require the ADS−R translation

function.

AUTOMATIC DIRECTION FINDER− An aircraft

radio navigation system which senses and indicates

the direction to a L/MF nondirectional radio beacon

(NDB) ground transmitter. Direction is indicated to

the pilot as a magnetic bearing or as a relative bearing

to the longitudinal axis of the aircraft depending on

the type of indicator installed in the aircraft. In certain

applications, such as military, ADF operations may

be based on airborne and ground transmitters in the

VHF/UHF frequency spectrum.

(See BEARING.)

(See NONDIRECTIONAL BEACON.)

AUTOMATIC FLIGHT INFORMATION SER-

VICE (AFIS) − ALASKA FSSs ONLY− The

continuous broadcast of recorded non−control

information at airports in Alaska where a FSS

provides local airport advisory service. The AFIS

broadcast automates the repetitive transmission of

essential but routine information such as weather,

wind, altimeter, favored runway, braking action,

airport NOTAMs, and other applicable information.

The information is continuously broadcast over a

discrete VHF radio frequency (usually the ASOS/

AWSS/AWOS frequency).

AUTOMATIC TERMINAL INFORMATION SER-

VICE− The continuous broadcast of recorded

noncontrol information in selected terminal areas. Its

purpose is to improve controller effectiveness and to

relieve frequency congestion by automating the

repetitive transmission of essential but routine

information; e.g., “Los Angeles information Alfa.

One three zero zero Coordinated Universal Time.

Weather, measured ceiling two thousand overcast,

visibility three, haze, smoke, temperature seven one,

dew point five seven, wind two five zero at five,

altimeter two niner niner six. I-L-S Runway Two Five

Left approach in use, Runway Two Five Right closed,

advise you have Alfa.”

(See ICAO term AUTOMATIC TERMINAL

INFORMATION SERVICE.)

(Refer to AIM.)

AUTOMATIC TERMINAL INFORMATION SER-

VICE [ICAO]− The provision of current, routine

information to arriving and departing aircraft by

means of continuous and repetitive broadcasts

throughout the day or a specified portion of the day.

AUTOROTATION− A rotorcraft flight condition in

which the lifting rotor is driven entirely by action of

the air when the rotorcraft is in motion.

a. Autorotative Landing/Touchdown Autorota-

tion. Used by a pilot to indicate that the landing will

be made without applying power to the rotor.

b. Low Level Autorotation. Commences at an

altitude well below the traffic pattern, usually below

100 feet AGL and is used primarily for tactical

military training.

c. 180 degrees Autorotation. Initiated from a

downwind heading and is commenced well inside the

normal traffic pattern. “Go around” may not be

possible during the latter part of this maneuver.

AVAILABLE LANDING DISTANCE (ALD)− The

portion of a runway available for landing and roll-out

for aircraft cleared for LAHSO. This distance is

measured from the landing threshold to the

hold-short point.

AVIATION WEATHER SERVICE− A service

provided by the National Weather Service (NWS) and

FAA which collects and disseminates pertinent

weather information for pilots, aircraft operators, and

ATC. Available aviation weather reports and

forecasts are displayed at each NWS office and FAA

FSS.

(See TRANSCRIBED WEATHER BROADCAST.)

(See WEATHER ADVISORY.)

(Refer to AIM.)

AWW−

(See SEVERE WEATHER FORECAST

ALERTS.)

Pilot/Controller Glossary

10/12/17

PCG B−1

BACK-TAXI− A term used by air traffic controllers

to taxi an aircraft on the runway opposite to the traffic

flow. The aircraft may be instructed to back-taxi to

the beginning of the runway or at some point before

reaching the runway end for the purpose of departure

or to exit the runway.

BASE LEG−

(See TRAFFIC PATTERN.)

BEACON−

(See AERONAUTICAL BEACON.)

(See AIRPORT ROTATING BEACON.)

(See AIRWAY BEACON.)

(See MARKER BEACON.)

(See NONDIRECTIONAL BEACON.)

(See RADAR.)

BEARING− The horizontal direction to or from any

point, usually measured clockwise from true north,

magnetic north, or some other reference point

through 360 degrees.

(See NONDIRECTIONAL BEACON.)

BELOW MINIMUMS− Weather conditions below

the minimums prescribed by regulation for the

particular action involved; e.g., landing minimums,

takeoff minimums.

BLAST FENCE− A barrier that is used to divert or

dissipate jet or propeller blast.

BLAST PAD− A surface adjacent to the ends of a

runway provided to reduce the erosive effect of jet

blast and propeller wash.

BLIND SPEED− The rate of departure or closing of

a target relative to the radar antenna at which

cancellation of the primary radar target by moving

target indicator (MTI) circuits in the radar equipment

causes a reduction or complete loss of signal.

(See ICAO term BLIND VELOCITY.)

BLIND SPOT− An area from which radio

transmissions and/or radar echoes cannot be

received. The term is also used to describe portions

of the airport not visible from the control tower.

BLIND TRANSMISSION−

(See TRANSMITTING IN THE BLIND.)

BLIND VELOCITY [ICAO]− The radial velocity of

a moving target such that the target is not seen on

primary radars fitted with certain forms of fixed echo

suppression.

BLIND ZONE−

(See BLIND SPOT.)

BLOCKED− Phraseology used to indicate that a

radio transmission has been distorted or interrupted

due to multiple simultaneous radio transmissions.

BOTTOM ALTITUDE– In reference to published

altitude restrictions on a STAR or STAR runway

transition, the lowest altitude authorized.

BOUNDARY LIGHTS

−

(See AIRPORT LIGHTING.)

BRAKING ACTION (GOOD, GOOD TO MEDI-

UM, MEDIUM, MEDIUM TO POOR, POOR, OR

NIL)− A report of conditions on the airport

movement area providing a pilot with a degree/quali-

ty of braking to expect. Braking action is reported in

terms of good, good to medium, medium, medium to

poor, poor, or nil.

(See RUNWAY CONDITION READING.)

(See RUNWAY CONDITION REPORT.)

(See RUNWAY CONDITION CODES.)

BRAKING ACTION ADVISORIES− When tower

controllers receive runway braking action reports

which include the terms “medium,” “poor,” or “nil,”

or whenever weather conditions are conducive to

deteriorating or rapidly changing runway braking

conditions, the tower will include on the ATIS

broadcast the statement, “Braking Action Advisories

are in Effect.” During the time braking action

advisories are in effect, ATC will issue the most

current braking action report for the runway in use to

each arriving and departing aircraft. Pilots should be

prepared for deteriorating braking conditions and

should request current runway condition information

if not issued by controllers. Pilots should also be

prepared to provide a descriptive runway condition

report to controllers after landing.

BREAKOUT− A technique to direct aircraft out of

the approach stream. In the context of simultaneous

(independent) parallel operations, a breakout is used

to direct threatened aircraft away from a deviating

aircraft.

Pilot/Controller Glossary 10/12/17

PCG B−2

BROADCAST− Transmission of information for

which an acknowledgement is not expected.

(See ICAO term BROADCAST.)

BROADCAST [ICAO]− A transmission of informa-

tion relating to air navigation that is not addressed to

a specific station or stations.

BUFFER AREA− As applied to an MVA or MIA

chart, a depicted three (3) or five (5) NM radius

MVA/MIA sector isolating a displayed obstacle for

which the sector is established. A portion of a buffer

area can also be inclusive of a MVA/MIA sector

polygon boundary.

Pilot/Controller Glossary

10/12/17

PCG C−1

CALCULATED LANDING TIME− A term that may

be used in place of tentative or actual calculated

landing time, whichever applies.

CALL FOR RELEASE− Wherein the overlying

ARTCC requires a terminal facility to initiate verbal

coordination to secure ARTCC approval for release

of a departure into the en route environment.

CALL UP− Initial voice contact between a facility

and an aircraft, using the identification of the unit

being called and the unit initiating the call.

(Refer to AIM.)

CANADIAN MINIMUM NAVIGATION PERFOR-

MANCE SPECIFICATION AIRSPACE− That

portion of Canadian domestic airspace within which

MNPS separation may be applied.

CARDINAL ALTITUDES− “Odd” or “Even”

thousand-foot altitudes or flight levels; e.g., 5,000,

6,000, 7,000, FL 250, FL 260, FL 270.

(See ALTITUDE.)

(See FLIGHT LEVEL.)

CARDINAL FLIGHT LEVELS−

(See CARDINAL ALTITUDES.)

CAT−

(See CLEAR-AIR TURBULENCE.)

CATCH POINT− A fix/waypoint that serves as a

transition point from the high altitude waypoint

navigation structure to an arrival procedure (STAR)

or the low altitude ground−based navigation

structure.

CEILING− The heights above the earth’s surface of

the lowest layer of clouds or obscuring phenomena

that is reported as “broken,” “overcast,” or

“obscuration,” and not classified as “thin” or

“partial.”

(See ICAO term CEILING.)

CEILING [ICAO]− The height above the ground or

water of the base of the lowest layer of cloud below

6,000 meters (20,000 feet) covering more than half

the sky.

CENRAP−

(See CENTER RADAR ARTS

PRESENTATION/PROCESSING.)

CENRAP-PLUS−

(See CENTER RADAR ARTS

PRESENTATION/PROCESSING- PLUS.)

CENTER−

(See AIR ROUTE TRAFFIC CONTROL

CENTER.)

CENTER’S AREA− The specified airspace within

which an air route traffic control center (ARTCC)

provides air traffic control and advisory service.

(See AIR ROUTE TRAFFIC CONTROL

CENTER.)

(Refer to AIM.)

CENTER RADAR ARTS PRESENTATION/

PROCESSING− A computer program developed to

provide a back-up system for airport surveillance

radar in the event of a failure or malfunction. The

program uses air route traffic control center radar for

the processing and presentation of data on the ARTS

IIA or IIIA displays.

CENTER RADAR ARTS PRESENTATION/

PROCESSING-PLUS− A computer program

developed to provide a back-up system for airport

surveillance radar in the event of a terminal secondary

radar system failure. The program uses a combination

of Air Route Traffic Control Center Radar and

terminal airport surveillance radar primary targets

displayed simultaneously for the processing and

presentation of data on the ARTS IIA or IIIA

displays.

CENTER TRACON AUTOMATION SYSTEM

(CTAS)− A computerized set of programs designed

to aid Air Route Traffic Control Centers and

TRACONs in the management and control of air

traffic.

CENTER WEATHER ADVISORY− An unsched-

uled weather advisory issued by Center Weather

Service Unit meteorologists for ATC use to alert

pilots of existing or anticipated adverse weather

conditions within the next 2 hours. A CWA may

modify or redefine a SIGMET.

(See AWW.)

(See AIRMET.)

(See CONVECTIVE SIGMET.)

(See SIGMET.)

(Refer to AIM.)

Pilot/Controller Glossary 10/12/17

PCG C−2

CENTRAL EAST PACIFIC− An organized route

system between the U.S. West Coast and Hawaii.

CEP−

(See CENTRAL EAST PACIFIC.)

CERAP−

(See COMBINED CENTER-RAPCON.)

CERTIFIED TOWER RADAR DISPLAY (CTRD)−

An FAA radar display certified for use in the NAS.

CFR−

(See CALL FOR RELEASE.)

CHAFF− Thin, narrow metallic reflectors of various

lengths and frequency responses, used to reflect radar

energy. These reflectors, when dropped from aircraft

and allowed to drift downward, result in large targets

on the radar display.

CHART SUPPLEMENT U.S.− A publication

designed primarily as a pilot’s operational manual

containing all airports, seaplane bases, and heliports

open to the public including communications data,

navigational facilities, and certain special notices and

procedures. This publication is issued in seven

volumes according to geographical area.

CHARTED VFR FLYWAYS− Charted VFR Fly-

ways are flight paths recommended for use to bypass

areas heavily traversed by large turbine-powered

aircraft. Pilot compliance with recommended

flyways and associated altitudes is strictly voluntary.

VFR Flyway Planning charts are published on the

back of existing VFR Terminal Area charts.

CHARTED VISUAL FLIGHT PROCEDURE

APPROACH− An approach conducted while

operating on an instrument flight rules (IFR) flight

plan which authorizes the pilot of an aircraft to

proceed visually and clear of clouds to the airport via

visual landmarks and other information depicted on

a charted visual flight procedure. This approach must

be authorized and under the control of the appropriate

air traffic control facility. Weather minimums

required are depicted on the chart.

CHASE− An aircraft flown in proximity to another

aircraft normally to observe its performance during

training or testing.

CHASE AIRCRAFT−

(See CHASE.)

CIRCLE-TO-LAND MANEUVER− A maneuver

initiated by the pilot to align the aircraft with a

runway for landing when a straight-in landing from

an instrument approach is not possible or is not

desirable. At tower controlled airports, this maneuver

is made only after ATC authorization has been

obtained and the pilot has established required visual

reference to the airport.

(See CIRCLE TO RUNWAY.)

(See LANDING MINIMUMS.)

(Refer to AIM.)

CIRCLE TO RUNWAY (RUNWAY NUMBER)−

Used by ATC to inform the pilot that he/she must

circle to land because the runway in use is other than

the runway aligned with the instrument approach

procedure. When the direction of the circling

maneuver in relation to the airport/runway is

required, the controller will state the direction (eight

cardinal compass points) and specify a left or right

downwind or base leg as appropriate; e.g., “Cleared

VOR Runway Three Six Approach circle to Runway

Two Two,” or “Circle northwest of the airport for a

right downwind to Runway Two Two.”

(See CIRCLE-TO-LAND MANEUVER.)

(See LANDING MINIMUMS.)

(Refer to AIM.)

CIRCLING APPROACH−

(See CIRCLE-TO-LAND MANEUVER.)

CIRCLING MANEUVER−

(See CIRCLE-TO-LAND MANEUVER.)

CIRCLING MINIMA−

(See LANDING MINIMUMS.)

CLASS A AIRSPACE−

(See CONTROLLED AIRSPACE.)

CLASS B AIRSPACE−

(See CONTROLLED AIRSPACE.)

CLASS C AIRSPACE−

(See CONTROLLED AIRSPACE.)

CLASS D AIRSPACE−

(See CONTROLLED AIRSPACE.)

CLASS E AIRSPACE−

(See CONTROLLED AIRSPACE.)

CLASS G AIRSPACE− That airspace not designated

as Class A, B, C, D or E.

CLEAR AIR TURBULENCE (CAT)− Turbulence

encountered in air where no clouds are present. This

term is commonly applied to high-level turbulence

Pilot/Controller Glossary

10/12/17

PCG C−3

associated with wind shear. CAT is often encountered

in the vicinity of the jet stream.

(See WIND SHEAR.)

(See JET STREAM.)

CLEAR OF THE RUNWAY−

a. Taxiing aircraft, which is approaching a

runway, is clear of the runway when all parts of the

aircraft are held short of the applicable runway

holding position marking.

b. A pilot or controller may consider an aircraft,

which is exiting or crossing a runway, to be clear of

the runway when all parts of the aircraft are beyond

the runway edge and there are no restrictions to its

continued movement beyond the applicable runway

holding position marking.

c. Pilots and controllers shall exercise good

judgement to ensure that adequate separation exists

between all aircraft on runways and taxiways at

airports with inadequate runway edge lines or

holding position markings.

CLEARANCE−

(See AIR TRAFFIC CLEARANCE.)

CLEARANCE LIMIT− The fix, point, or location to

which an aircraft is cleared when issued an air traffic

clearance.

(See ICAO term CLEARANCE LIMIT.)

CLEARANCE LIMIT [ICAO]− The point to which

an aircraft is granted an air traffic control clearance.

CLEARANCE VOID IF NOT OFF BY (TIME)−

Used by ATC to advise an aircraft that the departure

clearance is automatically canceled if takeoff is not

made prior to a specified time. The pilot must obtain

a new clearance or cancel his/her IFR flight plan if not

off by the specified time.

(See ICAO term CLEARANCE VOID TIME.)

CLEARANCE VOID TIME [ICAO]− A time

specified by an air traffic control unit at which a

clearance ceases to be valid unless the aircraft

concerned has already taken action to comply

therewith.

CLEARED APPROACH− ATC authorization for an

aircraft to execute any standard or special instrument

approach procedure for that airport. Normally, an

aircraft will be cleared for a specific instrument

approach procedure.

(See CLEARED (Type of) APPROACH.)

(See INSTRUMENT APPROACH

PROCEDURE.)

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

CLEARED (Type of) APPROACH− ATC authoriza-

tion for an aircraft to execute a specific instrument

approach procedure to an airport; e.g., “Cleared ILS

Runway Three Six Approach.”

(See APPROACH CLEARANCE.)

(See INSTRUMENT APPROACH

PROCEDURE.)

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

CLEARED AS FILED− Means the aircraft is cleared

to proceed in accordance with the route of flight filed

in the flight plan. This clearance does not include the

altitude, DP, or DP Transition.

(See REQUEST FULL ROUTE CLEARANCE.)

(Refer to AIM.)

CLEARED FOR TAKEOFF− ATC authorization

for an aircraft to depart. It is predicated on known

traffic and known physical airport conditions.

CLEARED FOR THE OPTION− ATC authoriza-

tion for an aircraft to make a touch-and-go, low

approach, missed approach, stop and go, or full stop

landing at the discretion of the pilot. It is normally

used in training so that an instructor can evaluate a

student’s performance under changing situations.

Pilots should advise ATC if they decide to remain on

the runway, of any delay in their stop and go, delay

clearing the runway, or are unable to comply with the

instruction(s).

(See OPTION APPROACH.)

(Refer to AIM.)

CLEARED THROUGH− ATC authorization for an

aircraft to make intermediate stops at specified

airports without refiling a flight plan while en route

to the clearance limit.

CLEARED TO LAND− ATC authorization for an

aircraft to land. It is predicated on known traffic and

known physical airport conditions.

CLEARWAY− An area beyond the takeoff runway

under the control of airport authorities within which

terrain or fixed obstacles may not extend above

Pilot/Controller Glossary 10/12/17

PCG C−4

specified limits. These areas may be required for

certain turbine-powered operations and the size and

upward slope of the clearway will differ depending on

when the aircraft was certificated.

(Refer to 14 CFR Part 1.)

CLIMB TO VFR− ATC authorization for an aircraft

to climb to VFR conditions within Class B, C, D, and

E surface areas when the only weather limitation is

restricted visibility. The aircraft must remain clear of

clouds while climbing to VFR.

(See SPECIAL VFR CONDITIONS.)

(Refer to AIM.)

CLIMBOUT− That portion of flight operation

between takeoff and the initial cruising altitude.

CLIMB VIA– An abbreviated ATC clearance that

requires compliance with the procedure lateral path,

associated speed restrictions, and altitude restrictions

along the cleared route or procedure.

CLOSE PARALLEL RUNWAYS− Two parallel

runways whose extended centerlines are separated by

less than 4,300 feet and at least 3000 feet (750 feet for

SOIA operations) for which ATC is authorized to

conduct simultaneous independent approach opera-

tions. PRM and simultaneous close parallel appear in

approach title. Dual communications, special pilot

training, an Attention All Users Page (AAUP), NTZ

monitoring by displays that have aural and visual

alerting algorithms are required. A high update rate

surveillance sensor is required for certain runway or

approach course spacing.

CLOSED RUNWAY− A runway that is unusable for

aircraft operations. Only the airport management/

military operations office can close a runway.

CLOSED TRAFFIC− Successive operations involv-

ing takeoffs and landings or low approaches where

the aircraft does not exit the traffic pattern.

CLOUD− A cloud is a visible accumulation of

minute water droplets and/or ice particles in the

atmosphere above the Earth’s surface. Cloud differs

from ground fog, fog, or ice fog only in that the latter

are, by definition, in contact with the Earth’s surface.

CLT−

(See CALCULATED LANDING TIME.)

CLUTTER− In radar operations, clutter refers to the

reception and visual display of radar returns caused

by precipitation, chaff, terrain, numerous aircraft

targets, or other phenomena. Such returns may limit

or preclude ATC from providing services based on

radar.

(See CHAFF.)

(See GROUND CLUTTER.)

(See PRECIPITATION.)

(See TARGET.)

(See ICAO term RADAR CLUTTER.)

CMNPS−

(See CANADIAN MINIMUM NAVIGATION

PERFORMANCE SPECIFICATION AIRSPACE.)

COASTAL FIX− A navigation aid or intersection

where an aircraft transitions between the domestic

route structure and the oceanic route structure.

CODES− The number assigned to a particular

multiple pulse reply signal transmitted by a

transponder.

(See DISCRETE CODE.)

COLD TEMPERATURE COMPENSATION− An

action on the part of the pilot to adjust an aircraft’s

indicated altitude due to the effect of cold

temperatures on true altitude above terrain versus

aircraft indicated altitude. The amount of

compensation required increases at a greater rate with

a decrease in temperature and increase in height

above the reporting station.

COLLABORATIVE TRAJECTORY OPTIONS

PROGRAM (CTOP)- CTOP is a traffic management

program administered by the Air Traffic Control

System Command Center (ATCSCC) that manages

demand through constrained airspace, while consid-

ering operator preference with regard to both route

and delay as defined in a Trajectory Options Set

(TOS).

COMBINED CENTER-RAPCON− An air traffic

facility which combines the functions of an ARTCC

and a radar approach control facility.

(See AIR ROUTE TRAFFIC CONTROL

CENTER.)

(See RADAR APPROACH CONTROL

FACILITY.)

COMMON POINT− A significant point over which

two or more aircraft will report passing or have

reported passing before proceeding on the same or

diverging tracks. To establish/maintain longitudinal

separation, a controller may determine a common

Pilot/Controller Glossary

10/12/17

PCG C−5

point not originally in the aircraft’s flight plan and

then clear the aircraft to fly over the point.

(See SIGNIFICANT POINT.)

COMMON PORTION−

(See COMMON ROUTE.)

COMMON ROUTE− That segment of a North

American Route between the inland navigation

facility and the coastal fix.

COMMON ROUTE− Typically the portion of a

RNAV STAR between the en route transition end

point and the runway transition start point; however,

the common route may only consist of a single point

that joins the en route and runway transitions.

COMMON TRAFFIC ADVISORY FREQUENCY

(CTAF)− A frequency designed for the purpose of

carrying out airport advisory practices while

operating to or from an airport without an operating

control tower. The CTAF may be a UNICOM,

Multicom, FSS, or tower frequency and is identified

in appropriate aeronautical publications.

(See DESIGNATED COMMON TRAFFIC

ADVISORY FREQUENCY (CTAF) AREA.)

(Refer to AC 90-42, Traffic Advisory Practices at

Airports Without Operating Control Towers.)

COMPASS LOCATOR− A low power, low or

medium frequency (L/MF) radio beacon installed at

the site of the outer or middle marker of an instrument

landing system (ILS). It can be used for navigation at

distances of approximately 15 miles or as authorized

in the approach procedure.

a. Outer Compass Locator (LOM)− A compass

locator installed at the site of the outer marker of an

instrument landing system.

(See OUTER MARKER.)

b. Middle Compass Locator (LMM)− A compass

locator installed at the site of the middle marker of an

instrument landing system.

(See MIDDLE MARKER.)

(See ICAO term LOCATOR.)

COMPASS ROSE− A circle, graduated in degrees,

printed on some charts or marked on the ground at an

airport. It is used as a reference to either true or

magnetic direction.

COMPLY WITH RESTRICTIONS− An ATC

instruction that requires an aircraft being vectored

back onto an arrival or departure procedure to comply

with all altitude and/or speed restrictions depicted on

the procedure. This term may be used in lieu of

repeating each remaining restriction that appears on

the procedure.

COMPOSITE FLIGHT PLAN− A flight plan which

specifies VFR operation for one portion of flight and

IFR for another portion. It is used primarily in

military operations.

(Refer to AIM.)

COMPOSITE ROUTE SYSTEM− An organized

oceanic route structure, incorporating reduced lateral

spacing between routes, in which composite

separation is authorized.

COMPOSITE SEPARATION− A method of separat-

ing aircraft in a composite route system where, by

management of route and altitude assignments, a

combination of half the lateral minimum specified for

the area concerned and half the vertical minimum is

applied.

COMPULSORY REPORTING POINTS− Reporting

points which must be reported to ATC. They are

designated on aeronautical charts by solid triangles or

filed in a flight plan as fixes selected to define direct

routes. These points are geographical locations

which are defined by navigation aids/fixes. Pilots

should discontinue position reporting over compul-

sory reporting points when informed by ATC that

their aircraft is in “radar contact.”

CONDITIONS NOT MONITORED− When an

airport operator cannot monitor the condition of the

movement area or airfield surface area, this

information is issued as a NOTAM. Usually

necessitated due to staffing, operating hours or other

mitigating factors associated with airport operations.

CONFIDENCE MANEUVER− A confidence man-

euver consists of one or more turns, a climb or

descent, or other maneuver to determine if the pilot

in command (PIC) is able to receive and comply with

ATC instructions.

CONFLICT ALERT− A function of certain air traffic

control automated systems designed to alert radar

controllers to existing or pending situations between

tracked targets (known IFR or VFR aircraft) that

require his/her immediate attention/action.

(See MODE C INTRUDER ALERT.)

CONFLICT RESOLUTION− The resolution of

potential conflictions between aircraft that are radar

identified and in communication with ATC by

Pilot/Controller Glossary 10/12/17

PCG C−6

ensuring that radar targets do not touch. Pertinent

traffic advisories shall be issued when this procedure

is applied.

Note: This procedure shall not be provided utilizing

mosaic radar systems.

CONFORMANCE− The condition established when

an aircraft’s actual position is within the conformance

region constructed around that aircraft at its position,

according to the trajectory associated with the

aircraft’s Current Plan.

CONFORMANCE REGION− A volume, bounded

laterally, vertically, and longitudinally, within which

an aircraft must be at a given time in order to be in

conformance with the Current Plan Trajectory for that

aircraft. At a given time, the conformance region is

determined by the simultaneous application of the

lateral, vertical, and longitudinal conformance

bounds for the aircraft at the position defined by time

and aircraft’s trajectory.

CONSOLAN− A low frequency, long-distance

NAVAID used principally for transoceanic naviga-

tions.

CONTACT−

a. Establish communication with (followed by the

name of the facility and, if appropriate, the frequency

to be used).

b. A flight condition wherein the pilot ascertains

the attitude of his/her aircraft and navigates by visual

reference to the surface.

(See CONTACT APPROACH.)

(See RADAR CONTACT.)

CONTACT APPROACH− An approach wherein an

aircraft on an IFR flight plan, having an air traffic

control authorization, operating clear of clouds with

at least 1 mile flight visibility and a reasonable

expectation of continuing to the destination airport in

those conditions, may deviate from the instrument

approach procedure and proceed to the destination

airport by visual reference to the surface. This

approach will only be authorized when requested by

the pilot and the reported ground visibility at the

destination airport is at least 1 statute mile.

(Refer to AIM.)

CONTAMINATED RUNWAY− A runway is

considered contaminated whenever standing water,

ice, snow, slush, frost in any form, heavy rubber, or

other substances are present. A runway is contami-

nated with respect to rubber deposits or other

friction-degrading substances when the average

friction value for any 500-foot segment of the runway

within the ALD fails below the recommended

minimum friction level and the average friction value

in the adjacent 500-foot segments falls below the

maintenance planning friction level.

CONTERMINOUS U.S.− The 48 adjoining States

and the District of Columbia.

CONTINENTAL UNITED STATES− The 49 States

located on the continent of North America and the

District of Columbia.

CONTINUE− When used as a control instruction

should be followed by another word or words

clarifying what is expected of the pilot. Example:

“continue taxi,” “continue descent,” “continue

inbound,” etc.

CONTROL AREA [ICAO]− A controlled airspace

extending upwards from a specified limit above the

earth.

CONTROL SECTOR− An airspace area of defined

horizontal and vertical dimensions for which a

controller or group of controllers has air traffic

control responsibility, normally within an air route

traffic control center or an approach control facility.

Sectors are established based on predominant traffic

flows, altitude strata, and controller workload. Pilot

communications during operations within a sector

are normally maintained on discrete frequencies

assigned to the sector.

(See DISCRETE FREQUENCY.)

CONTROL SLASH− A radar beacon slash repre-

senting the actual position of the associated aircraft.

Normally, the control slash is the one closest to the

interrogating radar beacon site. When ARTCC radar

is operating in narrowband (digitized) mode, the

control slash is converted to a target symbol.

CONTROLLED AIRSPACE− An airspace of

defined dimensions within which air traffic control

service is provided to IFR flights and to VFR flights

in accordance with the airspace classification.

a. Controlled airspace is a generic term that covers

Class A, Class B, Class C, Class D, and Class E

airspace.

b. Controlled airspace is also that airspace within

which all aircraft operators are subject to certain pilot

qualifications, operating rules, and equipment

requirements in 14 CFR Part 91 (for specific

Pilot/Controller Glossary

10/12/17

PCG C−7

operating requirements, please refer to 14 CFR

Part 91). For IFR operations in any class of controlled

airspace, a pilot must file an IFR flight plan and

receive an appropriate ATC clearance. Each Class B,

Class C, and Class D airspace area designated for an

airport contains at least one primary airport around

which the airspace is designated (for specific

designations and descriptions of the airspace classes,

please refer to 14 CFR Part 71).

c. Controlled airspace in the United States is

designated as follows:

1. CLASS A− Generally, that airspace from

18,000 feet MSL up to and including FL 600,

including the airspace overlying the waters within 12

nautical miles of the coast of the 48 contiguous States

and Alaska. Unless otherwise authorized, all persons

must operate their aircraft under IFR.

2. CLASS B− Generally, that airspace from the

surface to 10,000 feet MSL surrounding the nation’s

busiest airports in terms of airport operations or

passenger enplanements. The configuration of each

Class B airspace area is individually tailored and

consists of a surface area and two or more layers

(some Class B airspace areas resemble upside-down

wedding cakes), and is designed to contain all

published instrument procedures once an aircraft

enters the airspace. An ATC clearance is required for

all aircraft to operate in the area, and all aircraft that

are so cleared receive separation services within the

airspace. The cloud clearance requirement for VFR

operations is “clear of clouds.”

3. CLASS C− Generally, that airspace from the

surface to 4,000 feet above the airport elevation

(charted in MSL) surrounding those airports that

have an operational control tower, are serviced by a

radar approach control, and that have a certain

number of IFR operations or passenger enplane-

ments. Although the configuration of each Class C

area is individually tailored, the airspace usually

consists of a surface area with a 5 nautical mile (NM)

radius, a circle with a 10NM radius that extends no

lower than 1,200 feet up to 4,000 feet above the

airport elevation, and an outer area that is not charted.

Each person must establish two-way radio commu-

nications with the ATC facility providing air traffic

services prior to entering the airspace and thereafter

maintain those communications while within the

airspace. VFR aircraft are only separated from IFR

aircraft within the airspace.

(See OUTER AREA.)

4. CLASS D− Generally, that airspace from the

surface to 2,500 feet above the airport elevation

(charted in MSL) surrounding those airports that

have an operational control tower. The configuration

of each Class D airspace area is individually tailored

and when instrument procedures are published, the

airspace will normally be designed to contain the

procedures. Arrival extensions for instrument

approach procedures may be Class D or Class E

airspace. Unless otherwise authorized, each person

must establish two-way radio communications with

the ATC facility providing air traffic services prior to

entering the airspace and thereafter maintain those

communications while in the airspace. No separation

services are provided to VFR aircraft.

5. CLASS E− Generally, if the airspace is not

Class A, Class B, Class C, or Class D, and it is

controlled airspace, it is Class E airspace. Class E

airspace extends upward from either the surface or a

designated altitude to the overlying or adjacent

controlled airspace. When designated as a surface

area, the airspace will be configured to contain all

instrument procedures. Also in this class are Federal

airways, airspace beginning at either 700 or 1,200

feet AGL used to transition to/from the terminal or en

route environment, en route domestic, and offshore

airspace areas designated below 18,000 feet MSL.

Unless designated at a lower altitude, Class E

airspace begins at 14,500 MSL over the United

States, including that airspace overlying the waters

within 12 nautical miles of the coast of the 48

contiguous States and Alaska, up to, but not

including 18,000 feet MSL, and the airspace above

FL 600.

CONTROLLED AIRSPACE [ICAO]− An airspace

of defined dimensions within which air traffic control

service is provided to IFR flights and to VFR flights

in accordance with the airspace classification.

Note: Controlled airspace is a generic term which

covers ATS airspace Classes A, B, C, D, and E.

CONTROLLED TIME OF ARRIVAL− Arrival time

assigned during a Traffic Management Program. This

time may be modified due to adjustments or user

options.

CONTROLLER−

(See AIR TRAFFIC CONTROL SPECIALIST.)

CONTROLLER [ICAO]− A person authorized to

provide air traffic control services.

Pilot/Controller Glossary 10/12/17

PCG C−8

CONTROLLER PILOT DATA LINK

COMMUNICATIONS (CPDLC)− A two−way

digital communications system that conveys textual

air traffic control messages between controllers and

pilots using ground or satellite-based radio relay

stations.

CONVECTIVE SIGMET− A weather advisory

concerning convective weather significant to the

safety of all aircraft. Convective SIGMETs are issued

for tornadoes, lines of thunderstorms, embedded

thunderstorms of any intensity level, areas of

thunderstorms greater than or equal to VIP level 4

with an area coverage of

(40%) or more, and hail

inch or greater.

(See AIRMET.)

(See AWW.)

(See CWA.)

(See SIGMET.)

(Refer to AIM.)

CONVECTIVE SIGNIFICANT METEOROLOG-

ICAL INFORMATION−

(See CONVECTIVE SIGMET.)

COORDINATES− The intersection of lines of

reference, usually expressed in degrees/minutes/

seconds of latitude and longitude, used to determine

position or location.

COORDINATION FIX− The fix in relation to which

facilities will handoff, transfer control of an aircraft,

or coordinate flight progress data. For terminal

facilities, it may also serve as a clearance for arriving

aircraft.

COPTER−

(See HELICOPTER.)

CORRECTION− An error has been made in the

transmission and the correct version follows.

COUPLED APPROACH− An instrument approach

performed by the aircraft autopilot, and/or visually

depicted on the flight director, which is receiving

position information and/or steering commands from

onboard navigational equipment. In general, coupled

non-precision approaches must be flown manually

(autopilot disengaged) at altitudes lower than 50 feet

AGL below the minimum descent altitude, and

coupled precision approaches must be flown

manually (autopilot disengaged) below 50 feet AGL

unless authorized to conduct autoland operations.

Coupled instrument approaches are commonly flown

to the allowable IFR weather minima established by

the operator or PIC, or flown VFR for training and

safety.

COURSE−

a. The intended direction of flight in the horizontal

plane measured in degrees from north.

b. The ILS localizer signal pattern usually

specified as the front course or the back course.

(See BEARING.)

(See INSTRUMENT LANDING SYSTEM.)

(See RADIAL.)

CPDLC−

(See CONTROLLER PILOT DATA LINK

COMMUNICATIONS.)

CPL [ICAO]−

(See ICAO term CURRENT FLIGHT PLAN.)

CRITICAL ENGINE− The engine which, upon

failure, would most adversely affect the performance

or handling qualities of an aircraft.

CROSS (FIX) AT (ALTITUDE)− Used by ATC

when a specific altitude restriction at a specified fix

is required.

CROSS (FIX) AT OR ABOVE (ALTITUDE)− Used

by ATC when an altitude restriction at a specified fix

is required. It does not prohibit the aircraft from

crossing the fix at a higher altitude than specified;

however, the higher altitude may not be one that will

violate a succeeding altitude restriction or altitude

assignment.

(See ALTITUDE RESTRICTION.)

(Refer to AIM.)

CROSS (FIX) AT OR BELOW (ALTITUDE)−

Used by ATC when a maximum crossing altitude at

a specific fix is required. It does not prohibit the

aircraft from crossing the fix at a lower altitude;

however, it must be at or above the minimum IFR

altitude.

(See ALTITUDE RESTRICTION.)

(See MINIMUM IFR ALTITUDES.)

(Refer to 14 CFR Part 91.)

CROSSWIND−

a. When used concerning the traffic pattern, the

word means “crosswind leg.”

(See TRAFFIC PATTERN.)

Pilot/Controller Glossary

10/12/17

PCG C−9

b. When used concerning wind conditions, the

word means a wind not parallel to the runway or the

path of an aircraft.

(See CROSSWIND COMPONENT.)

CROSSWIND COMPONENT− The wind compo-

nent measured in knots at 90 degrees to the

longitudinal axis of the runway.

CRUISE− Used in an ATC clearance to authorize a

pilot to conduct flight at any altitude from the

minimum IFR altitude up to and including the

altitude specified in the clearance. The pilot may

level off at any intermediate altitude within this block

of airspace. Climb/descent within the block is to be

made at the discretion of the pilot. However, once the

pilot starts descent and verbally reports leaving an

altitude in the block, he/she may not return to that

altitude without additional ATC clearance. Further, it

is approval for the pilot to proceed to and make an

approach at destination airport and can be used in

conjunction with:

a. An airport clearance limit at locations with a

standard/special instrument approach procedure. The

CFRs require that if an instrument letdown to an

airport is necessary, the pilot shall make the letdown

in accordance with a standard/special instrument

approach procedure for that airport, or

b. An airport clearance limit at locations that are

within/below/outside controlled airspace and with-

out a standard/special instrument approach

procedure. Such a clearance is NOT AUTHORIZA-

TION for the pilot to descend under IFR conditions

below the applicable minimum IFR altitude nor does

it imply that ATC is exercising control over aircraft

in Class G airspace; however, it provides a means for

the aircraft to proceed to destination airport, descend,

and land in accordance with applicable CFRs

governing VFR flight operations. Also, this provides

search and rescue protection until such time as the

IFR flight plan is closed.

(See INSTRUMENT APPROACH

PROCEDURE.)

CRUISE CLIMB− A climb technique employed by

aircraft, usually at a constant power setting, resulting

in an increase of altitude as the aircraft weight

decreases.

CRUISING ALTITUDE− An altitude or flight level

maintained during en route level flight. This is a

constant altitude and should not be confused with a

cruise clearance.

(See ALTITUDE.)

(See ICAO term CRUISING LEVEL.)

CRUISING LEVEL−

(See CRUISING ALTITUDE.)

CRUISING LEVEL [ICAO]− A level maintained

during a significant portion of a flight.

CT MESSAGE− An EDCT time generated by the

ATCSCC to regulate traffic at arrival airports.

Normally, a CT message is automatically transferred

from the traffic management system computer to the

NAS en route computer and appears as an EDCT. In

the event of a communication failure between the

traffic management system computer and the NAS,

the CT message can be manually entered by the TMC

at the en route facility.

CTA−

(See CONTROLLED TIME OF ARRIVAL.)

(See ICAO term CONTROL AREA.)

CTAF−

(See COMMON TRAFFIC ADVISORY

FREQUENCY.)

CTAS−

(See CENTER TRACON AUTOMATION

SYSTEM.)

CTOP−

(See COLLABORATIVE TRAJECTORY

OPTIONS PROGRAM)

CTRD−

(See CERTIFIED TOWER RADAR DISPLAY.)

CURRENT FLIGHT PLAN [ICAO]− The flight

plan, including changes, if any, brought about by

subsequent clearances.

CURRENT PLAN− The ATC clearance the aircraft

has received and is expected to fly.

CVFP APPROACH−

(See CHARTED VISUAL FLIGHT PROCEDURE

APPROACH.)

CWA−

(See CENTER WEATHER ADVISORY and

WEATHER ADVISORY.)

Pilot/Controller Glossary

10/12/17

PCG D−1

D-ATIS−

(See DIGITAL-AUTOMATIC TERMINAL

INFORMATION SERVICE.)

D−ATIS [ICAO]−

(See ICAO Term DATA LINK AUTOMATIC

TERMINAL INFORMATION SERVICE.)

DA [ICAO]−

(See ICAO Term DECISION

ALTITUDE/DECISION HEIGHT.)

DAIR−

(See DIRECT ALTITUDE AND IDENTITY

READOUT.)

DANGER AREA [ICAO]− An airspace of defined

dimensions within which activities dangerous to the

flight of aircraft may exist at specified times.

Note: The term “Danger Area” is not used in

reference to areas within the United States or any

of its possessions or territories.

DAS−

(See DELAY ASSIGNMENT.)

DATA BLOCK−

(See ALPHANUMERIC DISPLAY.)

DATA LINK AUTOMATIC TERMINAL INFOR-

MATION SERVICE (D−ATIS) [ICAO]− The

provision of ATIS via data link.

DEAD RECKONING− Dead reckoning, as applied

to flying, is the navigation of an airplane solely by

means of computations based on airspeed, course,

heading, wind direction, and speed, groundspeed,

and elapsed time.

DECISION ALTITUDE/DECISION HEIGHT

[ICAO Annex 6]- A specified altitude or height (A/H)

in the precision approach at which a missed approach

must be initiated if the required visual reference to

continue the approach has not been established.

1. Decision altitude (DA) is referenced to mean sea

level and decision height (DH) is referenced to the

threshold elevation.

2. Category II and III minima are expressed as a DH

and not a DA. Minima is assessed by reference to a

radio altimeter and not a barometric altimeter, which

makes the minima a DH.

3. The required visual reference means that section of

the visual aids or of the approach area which should

have been in view for sufficient time for the pilot to

have made an assessment of the aircraft position and

rate of change of position, in relation to the desired

flight path.

DECISION ALTITUDE (DA)− A specified altitude

(mean sea level (MSL)) on an instrument approach

procedure (ILS, GLS, vertically guided RNAV) at

which the pilot must decide whether to continue the

approach or initiate an immediate missed approach if

the pilot does not see the required visual references.

DECISION HEIGHT (DH)− With respect to the

operation of aircraft, means the height at which a

decision must be made during an ILS or PAR

instrument approach to either continue the approach

or to execute a missed approach.

(See ICAO term DECISION

ALTITUDE/DECISION HEIGHT.)

DECODER− The device used to decipher signals

received from ATCRBS transponders to effect their

display as select codes.

(See CODES.)

(See RADAR.)

DEFENSE AREA– Any airspace of the contiguous

United States that is not an ADIZ in which the control

of aircraft is required for reasons of national security.

DEFENSE VISUAL FLIGHT RULES− Rules

applicable to flights within an ADIZ conducted under

the visual flight rules in 14 CFR Part 91.

(See AIR DEFENSE IDENTIFICATION ZONE.)

(Refer to 14 CFR Part 91.)

(Refer to 14 CFR Part 99.)

DELAY ASSIGNMENT (DAS)− Delays are distrib-

uted to aircraft based on the traffic management

program parameters. The delay assignment is

calculated in 15−minute increments and appears as a

table in Traffic Flow Management System (TFMS).

DELAY INDEFINITE (REASON IF KNOWN)

EXPECT FURTHER CLEARANCE (TIME)− Used

by ATC to inform a pilot when an accurate estimate

of the delay time and the reason for the delay cannot

immediately be determined; e.g., a disabled aircraft

Pilot/Controller Glossary 10/12/17

PCG D−2

on the runway, terminal or center area saturation,

weather below landing minimums, etc.

(See EXPECT FURTHER CLEARANCE (TIME).)

DELAY TIME− The amount of time that the arrival

must lose to cross the meter fix at the assigned meter

fix time. This is the difference between ACLT and

VTA.

DEPARTURE CENTER− The ARTCC having

jurisdiction for the airspace that generates a flight to

the impacted airport.

DEPARTURE CONTROL− A function of an

approach control facility providing air traffic control

service for departing IFR and, under certain

conditions, VFR aircraft.

(See APPROACH CONTROL FACILITY.)

(Refer to AIM.)

DEPARTURE SEQUENCING PROGRAM− A

program designed to assist in achieving a specified

interval over a common point for departures.

DEPARTURE TIME− The time an aircraft becomes

airborne.

DESCEND VIA– An abbreviated ATC clearance that

requires compliance with a published procedure

lateral path and associated speed restrictions and

provides a pilot-discretion descent to comply with

published altitude restrictions.

DESCENT SPEED ADJUSTMENTS− Speed decel-

eration calculations made to determine an accurate

VTA. These calculations start at the transition point

and use arrival speed segments to the vertex.

DESIGNATED COMMON TRAFFIC ADVISORY

FREQUENCY (CTAF) AREA- In Alaska, in

addition to being designated for the purpose of

carrying out airport advisory practices while

operating to or from an airport without an operating

airport traffic control tower, a CTAF may also be

designated for the purpose of carrying out advisory

practices for operations in and through areas with a

high volume of VFR traffic.

DESIRED COURSE−

a. True− A predetermined desired course direction

to be followed (measured in degrees from true north).

b. Magnetic− A predetermined desired course

direction to be followed (measured in degrees from

local magnetic north).

DESIRED TRACK− The planned or intended track

between two waypoints. It is measured in degrees

from either magnetic or true north. The instantaneous

angle may change from point to point along the great

circle track between waypoints.

DETRESFA (DISTRESS PHASE) [ICAO]− The

code word used to designate an emergency phase

wherein there is reasonable certainty that an aircraft

and its occupants are threatened by grave and

imminent danger or require immediate assistance.

DEVIATIONS−

a. A departure from a current clearance, such as an

off course maneuver to avoid weather or turbulence.

b. Where specifically authorized in the CFRs and

requested by the pilot, ATC may permit pilots to

deviate from certain regulations.

DH−

(See DECISION HEIGHT.)

DH [ICAO]−

(See ICAO Term DECISION ALTITUDE/

DECISION HEIGHT.)

DIGITAL-AUTOMATIC TERMINAL INFORMA-

TION SERVICE (D-ATIS)− The service provides

text messages to aircraft, airlines, and other users

outside the standard reception range of conventional

ATIS via landline and data link communications to

the cockpit. Also, the service provides a computer−

synthesized voice message that can be transmitted to

all aircraft within range of existing transmitters. The

Terminal Data Link System (TDLS) D-ATIS

application uses weather inputs from local automated

weather sources or manually entered meteorological

data together with preprogrammed menus to provide

standard information to users. Airports with D-ATIS

capability are listed in the Chart Supplement U.S.

DIGITAL TARGET− A computer−generated symbol

representing an aircraft’s position, based on a primary

return or radar beacon reply, shown on a digital

display.

DIGITAL TERMINAL AUTOMATION SYSTEM

(DTAS)− A system where digital radar and beacon

data is presented on digital displays and the

operational program monitors the system perfor-

mance on a real−time basis.

DIGITIZED TARGET− A computer−generated

indication shown on an analog radar display resulting

from a primary radar return or a radar beacon reply.

Pilot/Controller Glossary

10/12/17

PCG D−3

DIRECT− Straight line flight between two naviga-

tional aids, fixes, points, or any combination thereof.

When used by pilots in describing off-airway routes,

points defining direct route segments become

compulsory reporting points unless the aircraft is

under radar contact.

DIRECTLY BEHIND− An aircraft is considered to

be operating directly behind when it is following the

actual flight path of the lead aircraft over the surface

of the earth except when applying wake turbulence

separation criteria.

DISCRETE BEACON CODE−

(See DISCRETE CODE.)

DISCRETE CODE− As used in the Air Traffic

Control Radar Beacon System (ATCRBS), any one

of the 4096 selectable Mode 3/A aircraft transponder

codes except those ending in zero zero; e.g., discrete

codes: 0010, 1201, 2317, 7777; nondiscrete codes:

0100, 1200, 7700. Nondiscrete codes are normally

reserved for radar facilities that are not equipped with

discrete decoding capability and for other purposes

such as emergencies (7700), VFR aircraft (1200), etc.

(See RADAR.)

(Refer to AIM.)

DISCRETE FREQUENCY− A separate radio

frequency for use in direct pilot-controller commu-

nications in air traffic control which reduces

frequency congestion by controlling the number of

aircraft operating on a particular frequency at one

time. Discrete frequencies are normally designated

for each control sector in en route/terminal ATC

facilities. Discrete frequencies are listed in the Chart

Supplement U.S. and the DOD FLIP IFR En Route

Supplement.

(See CONTROL SECTOR.)

DISPLACED THRESHOLD− A threshold that is

located at a point on the runway other than the

designated beginning of the runway.

(See THRESHOLD.)

(Refer to AIM.)

DISTANCE MEASURING EQUIPMENT (DME)−

Equipment (airborne and ground) used to measure, in

nautical miles, the slant range distance of an aircraft

from the DME navigational aid.

(See TACAN.)

(See VORTAC.)

DISTRESS− A condition of being threatened by

serious and/or imminent danger and of requiring

immediate assistance.

DIVE BRAKES−

(See SPEED BRAKES.)

DIVERSE VECTOR AREA− In a radar environ-

ment, that area in which a prescribed departure route

is not required as the only suitable route to avoid

obstacles. The area in which random radar vectors

below the MVA/MIA, established in accordance with

the TERPS criteria for diverse departures, obstacles

and terrain avoidance, may be issued to departing

aircraft.

DIVERSION (DVRSN)− Flights that are required to

land at other than their original destination for

reasons beyond the control of the pilot/company, e.g.

periods of significant weather.

DME−

(See DISTANCE MEASURING EQUIPMENT.)

DME FIX− A geographical position determined by

reference to a navigational aid which provides

distance and azimuth information. It is defined by a

specific distance in nautical miles and a radial,

azimuth, or course (i.e., localizer) in degrees

magnetic from that aid.

(See DISTANCE MEASURING EQUIPMENT.)

(See FIX.)

DME SEPARATION− Spacing of aircraft in terms of

distances (nautical miles) determined by reference to

distance measuring equipment (DME).

(See DISTANCE MEASURING EQUIPMENT.)

DOD FLIP− Department of Defense Flight Informa-

tion Publications used for flight planning, en route,

and terminal operations. FLIP is produced by the

National Geospatial−Intelligence Agency (NGA) for

world-wide use. United States Government Flight

Information Publications (en route charts and

instrument approach procedure charts) are incorpo-

rated in DOD FLIP for use in the National Airspace

System (NAS).

DOMESTIC AIRSPACE− Airspace which overlies

the continental land mass of the United States plus

Hawaii and U.S. possessions. Domestic airspace

extends to 12 miles offshore.

DOWNBURST− A strong downdraft which induces

an outburst of damaging winds on or near the ground.

Damaging winds, either straight or curved, are highly

Pilot/Controller Glossary 10/12/17

PCG D−4

divergent. The sizes of downbursts vary from 1/2

mile or less to more than 10 miles. An intense

downburst often causes widespread damage. Damag-

ing winds, lasting 5 to 30 minutes, could reach speeds

as high as 120 knots.

DOWNWIND LEG−

(See TRAFFIC PATTERN.)

DP−

(See INSTRUMENT DEPARTURE PROCEDURE.)

DRAG CHUTE− A parachute device installed on

certain aircraft which is deployed on landing roll to

assist in deceleration of the aircraft.

DROP ZONE− Any pre-determined area upon which

parachutists or objects land after making an

intentional parachute jump or drop.

(Refer to 14 CFR §105.3, Definitions)

DSP−

(See DEPARTURE SEQUENCING PROGRAM.)

DT−

(See DELAY TIME.)

DTAS−

(See DIGITAL TERMINAL AUTOMATION

SYSTEM.)

DUE REGARD− A phase of flight wherein an

aircraft commander of a State-operated aircraft

assumes responsibility to separate his/her aircraft

from all other aircraft.

(See also FAA Order JO 7110.65, Para 1−2−1,

WORD MEANINGS.)

DUTY RUNWAY−

(See RUNWAY IN USE/ACTIVE RUNWAY/DUTY

RUNWAY.)

DVA−

(See DIVERSE VECTOR AREA.)

DVFR−

(See DEFENSE VISUAL FLIGHT RULES.)

DVFR FLIGHT PLAN− A flight plan filed for a VFR

aircraft which intends to operate in airspace within

which the ready identification, location, and control

of aircraft are required in the interest of national

security.

DVRSN−

(See DIVERSION.)

DYNAMIC− Continuous review, evaluation, and

change to meet demands.

DYNAMIC RESTRICTIONS− Those restrictions

imposed by the local facility on an “as needed” basis

to manage unpredictable fluctuations in traffic

demands.

Pilot/Controller Glossary

10/12/17

PCG E−1

EAS−

(See EN ROUTE AUTOMATION SYSTEM.)

EDCT−

(See EXPECT DEPARTURE CLEARANCE

TIME.)

EDST−

(See EN ROUTE DECISION SUPPORT TOOL)

EFC−

(See EXPECT FURTHER CLEARANCE (TIME).)

ELT−

(See EMERGENCY LOCATOR TRANSMITTER.)

EMERGENCY− A distress or an urgency condition.

EMERGENCY LOCATOR TRANSMITTER− A

radio transmitter attached to the aircraft structure

which operates from its own power source on

121.5 MHz and 243.0 MHz. It aids in locating

downed aircraft by radiating a downward sweeping

audio tone, 2-4 times per second. It is designed to

function without human action after an accident.

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

E-MSAW−

(See EN ROUTE MINIMUM SAFE ALTITUDE

WARNING.)

ENHANCED FLIGHT VISION SYSTEM (EFVS)−

An EFVS is an installed aircraft system which uses

an electronic means to provide a display of the

forward external scene topography (the natural or

man−made features of a place or region especially in

a way to show their relative positions and elevation)

through the use of imaging sensors, including but not

limited to forward−looking infrared, millimeter wave

radiometry, millimeter wave radar, or low−light level

image intensification. An EFVS includes the display

element, sensors, computers and power supplies,

indications, and controls. An operator’s authoriza-

tion to conduct an EFVS operation may have

provisions which allow pilots to conduct IAPs when

the reported weather is below minimums prescribed

on the IAP to be flown.

EN ROUTE AIR TRAFFIC CONTROL SER-

VICES− Air traffic control service provided aircraft

on IFR flight plans, generally by centers, when these

aircraft are operating between departure and

destination terminal areas. When equipment, capa-

bilities, and controller workload permit, certain

advisory/assistance services may be provided to VFR

aircraft.

(See AIR ROUTE TRAFFIC CONTROL

CENTER.)

(Refer to AIM.)

EN ROUTE AUTOMATION SYSTEM (EAS)− The

complex integrated environment consisting of

situation display systems, surveillance systems and

flight data processing, remote devices, decision

support tools, and the related communications

equipment that form the heart of the automated IFR

air traffic control system. It interfaces with automated

terminal systems and is used in the control of en route

IFR aircraft.

(Refer to AIM.)

EN ROUTE CHARTS−

(See AERONAUTICAL CHART.)

EN ROUTE DECISION SUPPORT TOOL− An

automated tool provided at each Radar Associate

position in selected En Route facilities. This tool

utilizes flight and radar data to determine present and

future trajectories for all active and proposal aircraft

and provides enhanced automated flight data

management.

EN ROUTE DESCENT− Descent from the en route

cruising altitude which takes place along the route of

flight.

EN ROUTE HIGH ALTITUDE CHARTS−

(See AERONAUTICAL CHART.)

EN ROUTE LOW ALTITUDE CHARTS−

(See AERONAUTICAL CHART.)

EN ROUTE MINIMUM SAFE ALTITUDE WARN-

ING− A function of the EAS that aids the controller

by providing an alert when a tracked aircraft is below

or predicted by the computer to go below a

predetermined minimum IFR altitude (MIA).

EN ROUTE SPACING PROGRAM (ESP)− A

program designed to assist the exit sector in

achieving the required in-trail spacing.

Pilot/Controller Glossary 10/12/17

PCG E−2

EN ROUTE TRANSITION−

a. Conventional STARs/SIDs. The portion of a

SID/STAR that connects to one or more en route

airway/jet route.

b. RNAV STARs/SIDs. The portion of a STAR

preceding the common route or point, or for a SID the

portion following, that is coded for a specific en route

fix, airway or jet route.

ESP−

(See EN ROUTE SPACING PROGRAM.)

EST−

(See ESTIMATED.)

ESTABLISHED− To be stable or fixed at an altitude

or on a course, route, route segment, heading,

instrument approach or departure procedure, etc.

ESTIMATED (EST)−When used in NOTAMs

“EST” is a contraction that is used by the issuing

authority only when the condition is expected to

return to service prior to the expiration time. Using

“EST” lets the user know that this NOTAM has the

possibility of returning to service earlier than the

expiration time. Any NOTAM which includes an

“EST” will be auto−expired at the designated

expiration time.

ESTIMATED ELAPSED TIME [ICAO]− The

estimated time required to proceed from one

significant point to another.

(See ICAO Term TOTAL ESTIMATED ELAPSED

TIME.)

ESTIMATED OFF-BLOCK TIME [ICAO]− The

estimated time at which the aircraft will commence

movement associated with departure.

ESTIMATED POSITION ERROR (EPE)−

(See Required Navigation Performance)

ESTIMATED TIME OF ARRIVAL− The time the

flight is estimated to arrive at the gate (scheduled

operators) or the actual runway on times for

nonscheduled operators.

ESTIMATED TIME EN ROUTE− The estimated

flying time from departure point to destination

(lift-off to touchdown).

ETA−

(See ESTIMATED TIME OF ARRIVAL.)

ETE−

(See ESTIMATED TIME EN ROUTE.)

EXECUTE MISSED APPROACH− Instructions

issued to a pilot making an instrument approach

which means continue inbound to the missed

approach point and execute the missed approach

procedure as described on the Instrument Approach

Procedure Chart or as previously assigned by ATC.

The pilot may climb immediately to the altitude

specified in the missed approach procedure upon

making a missed approach. No turns should be

initiated prior to reaching the missed approach point.

When conducting an ASR or PAR approach, execute

the assigned missed approach procedure immediately

upon receiving instructions to “execute missed

approach.”

(Refer to AIM.)

EXPECT (ALTITUDE) AT (TIME) or (FIX)− Used

under certain conditions to provide a pilot with an

altitude to be used in the event of two-way

communications failure. It also provides altitude

information to assist the pilot in planning.

(Refer to AIM.)

EXPECT DEPARTURE CLEARANCE TIME

(EDCT)− The runway release time assigned to an

aircraft in a traffic management program and shown

on the flight progress strip as an EDCT.

(See GROUND DELAY PROGRAM.)

EXPECT FURTHER CLEARANCE (TIME)− The

time a pilot can expect to receive clearance beyond a

clearance limit.

EXPECT FURTHER CLEARANCE VIA (AIR-

WAYS, ROUTES OR FIXES)− Used to inform a

pilot of the routing he/she can expect if any part of the

route beyond a short range clearance limit differs

from that filed.

EXPEDITE− Used by ATC when prompt com-

pliance is required to avoid the development of an

imminent situation. Expedite climb/descent normal-

ly indicates to a pilot that the approximate best rate

of climb/descent should be used without requiring an

exceptional change in aircraft handling characteris-

tics.

Pilot/Controller Glossary

10/12/17

PCG F−1

FAF−

(See FINAL APPROACH FIX.)

FAST FILE− An FSS system whereby a pilot files a

flight plan via telephone that is recorded and later

transcribed for transmission to the appropriate air

traffic facility. (Alaska only.)

FAWP− Final Approach Waypoint

FCLT−

(See FREEZE CALCULATED LANDING TIME.)

FEATHERED PROPELLER− A propeller whose

blades have been rotated so that the leading and

trailing edges are nearly parallel with the aircraft

flight path to stop or minimize drag and engine

rotation. Normally used to indicate shutdown of a

reciprocating or turboprop engine due to malfunc-

tion.

FEDERAL AIRWAYS−

(See LOW ALTITUDE AIRWAY STRUCTURE.)

FEEDER FIX− The fix depicted on Instrument

Approach Procedure Charts which establishes the

starting point of the feeder route.

FEEDER ROUTE− A route depicted on instrument

approach procedure charts to designate routes for

aircraft to proceed from the en route structure to the

initial approach fix (IAF).

(See INSTRUMENT APPROACH

PROCEDURE.)

FERRY FLIGHT− A flight for the purpose of:

a. Returning an aircraft to base.

b. Delivering an aircraft from one location to

another.

c. Moving an aircraft to and from a maintenance

base.− Ferry flights, under certain conditions, may be

conducted under terms of a special flight permit.

FIELD ELEVATION−

(See AIRPORT ELEVATION.)

FILED− Normally used in conjunction with flight

plans, meaning a flight plan has been submitted to

ATC.

FILED EN ROUTE DELAY− Any of the following

preplanned delays at points/areas along the route of

flight which require special flight plan filing and

handling techniques.

a. Terminal Area Delay. A delay within a terminal

area for touch-and-go, low approach, or other

terminal area activity.

b. Special Use Airspace Delay. A delay within a

Military Operations Area, Restricted Area, Warning

Area, or ATC Assigned Airspace.

c. Aerial Refueling Delay. A delay within an

Aerial Refueling Track or Anchor.

FILED FLIGHT PLAN− The flight plan as filed with

an ATS unit by the pilot or his/her designated

representative without any subsequent changes or

clearances.

FINAL− Commonly used to mean that an aircraft is

on the final approach course or is aligned with a

landing area.

(See FINAL APPROACH COURSE.)

(See FINAL APPROACH-IFR.)

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

FINAL APPROACH [ICAO]− That part of an

instrument approach procedure which commences at

the specified final approach fix or point, or where

such a fix or point is not specified.

a. At the end of the last procedure turn, base turn

or inbound turn of a racetrack procedure, if specified;

b. At the point of interception of the last track

specified in the approach procedure; and ends at a

point in the vicinity of an aerodrome from which:

1. A landing can be made; or

2. A missed approach procedure is initiated.

FINAL APPROACH COURSE− A bearing/radial/

track of an instrument approach leading to a runway

or an extended runway centerline all without regard

to distance.

FINAL APPROACH FIX− The fix from which the

final approach (IFR) to an airport is executed and

which identifies the beginning of the final approach

segment. It is designated on Government charts by

the Maltese Cross symbol for nonprecision

approaches and the lightning bolt symbol,

designating the PFAF, for precision approaches; or

Pilot/Controller Glossary 10/12/17

PCG F−2

when ATC directs a lower-than-published

glideslope/path or vertical path intercept altitude, it is

the resultant actual point of the glideslope/path or

vertical path intercept.

(See FINAL APPROACH POINT.)

(See GLIDESLOPE INTERCEPT ALTITUDE.)

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

FINAL APPROACH-IFR− The flight path of an

aircraft which is inbound to an airport on a final

instrument approach course, beginning at the final

approach fix or point and extending to the airport or

the point where a circle-to-land maneuver or a missed

approach is executed.

(See FINAL APPROACH COURSE.)

(See FINAL APPROACH FIX.)

(See FINAL APPROACH POINT.)

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

(See ICAO term FINAL APPROACH.)

FINAL APPROACH POINT− The point, applicable

only to a nonprecision approach with no depicted

FAF (such as an on airport VOR), where the aircraft

is established inbound on the final approach course

from the procedure turn and where the final approach

descent may be commenced. The FAP serves as the

FAF and identifies the beginning of the final

approach segment.

(See FINAL APPROACH FIX.)

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

FINAL APPROACH SEGMENT−

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

FINAL APPROACH SEGMENT [ICAO]− That

segment of an instrument approach procedure in

which alignment and descent for landing are

accomplished.

FINAL CONTROLLER− The controller providing

information and final approach guidance during PAR

and ASR approaches utilizing radar equipment.

(See RADAR APPROACH.)

FINAL GUARD SERVICE− A value added service

provided in conjunction with LAA/RAA only during

periods of significant and fast changing weather

conditions that may affect landing and takeoff

operations.

FINAL MONITOR AID− A high resolution color

display that is equipped with the controller alert

system hardware/software used to monitor the no

transgression zone (NTZ) during simultaneous

parallel approach operations. The display includes

alert algorithms providing the target predictors, a

color change alert when a target penetrates or is

predicted to penetrate the no transgression zone

(NTZ), synthesized voice alerts, and digital mapping.

(See RADAR APPROACH.)

FINAL MONITOR CONTROLLER− Air Traffic

Control Specialist assigned to radar monitor the

flight path of aircraft during simultaneous parallel

(approach courses spaced less than 9000 feet/9200

feet above 5000 feet) and simultaneous close parallel

approach operations. Each runway is assigned a final

monitor controller during simultaneous parallel and

simultaneous close parallel ILS approaches.

FIR−

(See FLIGHT INFORMATION REGION.)

FIRST TIER CENTER− The ARTCC immediately

adjacent to the impacted center.

FIS−B−

(See FLIGHT INFORMATION

SERVICE−BROADCAST.)

FIX− A geographical position determined by visual

reference to the surface, by reference to one or more

radio NAVAIDs, by celestial plotting, or by another

navigational device.

FIX BALANCING− A process whereby aircraft are

evenly distributed over several available arrival fixes

reducing delays and controller workload.

FLAG− A warning device incorporated in certain

airborne navigation and flight instruments indicating

that:

a. Instruments are inoperative or otherwise not

operating satisfactorily, or

b. Signal strength or quality of the received signal

falls below acceptable values.

FLAG ALARM−

(See FLAG.)

FLAMEOUT− An emergency condition caused by a

loss of engine power.

FLAMEOUT PATTERN− An approach normally

conducted by a single-engine military aircraft

experiencing loss or anticipating loss of engine

Pilot/Controller Glossary

10/12/17

PCG F−3

power or control. The standard overhead approach

starts at a relatively high altitude over a runway

(“high key”) followed by a continuous 180 degree

turn to a high, wide position (“low key”) followed by

a continuous 180 degree turn final. The standard

straight-in pattern starts at a point that results in a

straight-in approach with a high rate of descent to the

runway. Flameout approaches terminate in the type

approach requested by the pilot (normally fullstop).

FLIGHT CHECK− A call-sign prefix used by FAA

aircraft engaged in flight inspection/certification of

navigational aids and flight procedures. The word

“recorded” may be added as a suffix; e.g., “Flight

Check 320 recorded” to indicate that an automated

flight inspection is in progress in terminal areas.

(See FLIGHT INSPECTION.)

(Refer to AIM.)

FLIGHT FOLLOWING−

(See TRAFFIC ADVISORIES.)

FLIGHT INFORMATION REGION− An airspace of

defined dimensions within which Flight Information

Service and Alerting Service are provided.

a. Flight Information Service. A service provided

for the purpose of giving advice and information

useful for the safe and efficient conduct of flights.

b. Alerting Service. A service provided to notify

appropriate organizations regarding aircraft in need

of search and rescue aid and to assist such

organizations as required.

FLIGHT INFORMATION SERVICE− A service

provided for the purpose of giving advice and

information useful for the safe and efficient conduct

of flights.

FLIGHT INFORMATION SERVICE−

BROADCAST (FIS−B)− A ground broadcast service

provided through the ADS−B Broadcast Services

network over the UAT data link that operates on 978

MHz. The FIS−B system provides pilots and flight

crews of properly equipped aircraft with a cockpit

display of certain aviation weather and aeronautical

information.

FLIGHT INSPECTION− Inflight investigation and

evaluation of a navigational aid to determine whether

it meets established tolerances.

(See FLIGHT CHECK.)

(See NAVIGATIONAL AID.)

FLIGHT LEVEL− A level of constant atmospheric

pressure related to a reference datum of 29.92 inches

of mercury. Each is stated in three digits that represent

hundreds of feet. For example, flight level (FL) 250

represents a barometric altimeter indication of

25,000 feet; FL 255, an indication of 25,500 feet.

(See ICAO term FLIGHT LEVEL.)

FLIGHT LEVEL [ICAO]− A surface of constant

atmospheric pressure which is related to a specific

pressure datum, 1013.2 hPa (1013.2 mb), and is

separated from other such surfaces by specific

pressure intervals.

Note 1: A pressure type altimeter calibrated in

accordance with the standard atmosphere:

a. When set to a QNH altimeter setting, will

indicate altitude;

b. When set to a QFE altimeter setting, will

indicate height above the QFE reference datum;

and

c. When set to a pressure of 1013.2 hPa

(1013.2 mb), may be used to indicate flight levels.

Note 2: The terms ‘height’ and ‘altitude,’ used in

Note 1 above, indicate altimetric rather than

geometric heights and altitudes.

FLIGHT LINE− A term used to describe the precise

movement of a civil photogrammetric aircraft along

a predetermined course(s) at a predetermined altitude

during the actual photographic run.

FLIGHT MANAGEMENT SYSTEMS− A comput-

er system that uses a large data base to allow routes

to be preprogrammed and fed into the system by

means of a data loader. The system is constantly

updated with respect to position accuracy by

reference to conventional navigation aids. The

sophisticated program and its associated data base

ensures that the most appropriate aids are automati-

cally selected during the information update cycle.

FLIGHT PATH− A line, course, or track along which

an aircraft is flying or intended to be flown.

(See COURSE.)

(See TRACK.)

FLIGHT PLAN− Specified information relating to

the intended flight of an aircraft that is filed orally or

in writing with an FSS or an ATC facility.

(See FAST FILE.)

(See FILED.)

(Refer to AIM.)

FLIGHT PLAN AREA (FPA)− The geographical

area assigned to a flight service station (FSS) for the

Pilot/Controller Glossary 10/12/17

PCG F−4

purpose of establishing primary responsibility for

services that may include search and rescue for VFR

aircraft, issuance of NOTAMs, pilot briefings,

inflight services, broadcast services, emergency

services, flight data processing, international opera-

tions, and aviation weather services. Large

consolidated FSS facilities may combine FPAs into

larger areas of responsibility (AOR).

(See FLIGHT SERVICE STATION.)

(See TIE-IN FACILITY.)

FLIGHT RECORDER− A general term applied to

any instrument or device that records information

about the performance of an aircraft in flight or about

conditions encountered in flight. Flight recorders

may make records of airspeed, outside air

temperature, vertical acceleration, engine RPM,

manifold pressure, and other pertinent variables for a

given flight.

(See ICAO term FLIGHT RECORDER.)

FLIGHT RECORDER [ICAO]− Any type of

recorder installed in the aircraft for the purpose of

complementing accident/incident investigation.

Note: See Annex 6 Part I, for specifications relating

to flight recorders.

FLIGHT SERVICE STATION (FSS)− An air traffic

facility which provides pilot briefings, flight plan

processing, en route flight advisories, search and

rescue services, and assistance to lost aircraft and

aircraft in emergency situations. FSS also relay ATC

clearances, process Notices to Airmen, broadcast

aviation weather and aeronautical information, and

advise Customs and Immigration of transborder

flights. In Alaska, FSS provide Airport Advisory

Services.

(See FLIGHT PLAN AREA.)

(See TIE-IN FACILITY.)

FLIGHT STANDARDS DISTRICT OFFICE− An

FAA field office serving an assigned geographical

area and staffed with Flight Standards personnel who

serve the aviation industry and the general public on

matters relating to the certification and operation of

air carrier and general aviation aircraft. Activities

include general surveillance of operational safety,

certification of airmen and aircraft, accident

prevention, investigation, enforcement, etc.

FLIGHT TERMINATION− The intentional and

deliberate process of terminating the flight of a UA in

the event of an unrecoverable lost link, loss of

control, or other failure that compromises the safety

of flight.

FLIGHT TEST− A flight for the purpose of:

a. Investigating the operation/flight characteris-

tics of an aircraft or aircraft component.

b. Evaluating an applicant for a pilot certificate or

rating.

FLIGHT VISIBILITY−

(See VISIBILITY.)

FLIP−

(See DOD FLIP.)

FLY HEADING (DEGREES)− Informs the pilot of

the heading he/she should fly. The pilot may have to

turn to, or continue on, a specific compass direction

in order to comply with the instructions. The pilot is

expected to turn in the shorter direction to the heading

unless otherwise instructed by ATC.

FLY-BY WAYPOINT− A fly-by waypoint requires

the use of turn anticipation to avoid overshoot of the

next flight segment.

FLY-OVER WAYPOINT− A fly-over waypoint

precludes any turn until the waypoint is overflown

and is followed by an intercept maneuver of the next

flight segment.

FLY VISUAL TO AIRPORT−

(See PUBLISHED INSTRUMENT APPROACH

PROCEDURE VISUAL SEGMENT.)

FMA−

(See FINAL MONITOR AID.)

FMS−

(See FLIGHT MANAGEMENT SYSTEM.)

FORMATION FLIGHT− More than one aircraft

which, by prior arrangement between the pilots,

operate as a single aircraft with regard to navigation

and position reporting. Separation between aircraft

within the formation is the responsibility of the flight

leader and the pilots of the other aircraft in the flight.

This includes transition periods when aircraft within

the formation are maneuvering to attain separation

from each other to effect individual control and

during join-up and breakaway.

a. A standard formation is one in which a

proximity of no more than 1 mile laterally or

longitudinally and within 100 feet vertically from the

flight leader is maintained by each wingman.

b. Nonstandard formations are those operating

under any of the following conditions:

Pilot/Controller Glossary

10/12/17

PCG F−5

1. When the flight leader has requested and ATC

has approved other than standard formation

dimensions.

2. When operating within an authorized altitude

reservation (ALTRV) or under the provisions of a

letter of agreement.

3. When the operations are conducted in

airspace specifically designed for a special activity.

(See ALTITUDE RESERVATION.)

(Refer to 14 CFR Part 91.)

FRC−

(See REQUEST FULL ROUTE CLEARANCE.)

FREEZE/FROZEN− Terms used in referring to

arrivals which have been assigned ACLTs and to the

lists in which they are displayed.

FREEZE CALCULATED LANDING TIME− A

dynamic parameter number of minutes prior to the

meter fix calculated time of arrival for each aircraft

when the TCLT is frozen and becomes an ACLT (i.e.,

the VTA is updated and consequently the TCLT is

modified as appropriate until FCLT minutes prior to

meter fix calculated time of arrival, at which time

updating is suspended and an ACLT and a frozen

meter fix crossing time (MFT) is assigned).

FREEZE HORIZON− The time or point at which an

aircraft’s STA becomes fixed and no longer fluctuates

with each radar update. This setting ensures a

constant time for each aircraft, necessary for the

metering controller to plan his/her delay technique.

This setting can be either in distance from the meter

fix or a prescribed flying time to the meter fix.

FREEZE SPEED PARAMETER− A speed adapted

for each aircraft to determine fast and slow aircraft.

Fast aircraft freeze on parameter FCLT and slow

aircraft freeze on parameter MLDI.

FRICTION MEASUREMENT− A measurement of

the friction characteristics of the runway pavement

surface using continuous self-watering friction

measurement equipment in accordance with the

specifications, procedures and schedules contained

in AC 150/5320−12, Measurement, Construction,

and Maintenance of Skid Resistant Airport Pavement

Surfaces.

FSDO−

(See FLIGHT STANDARDS DISTRICT OFFICE.)

FSPD−

(See FREEZE SPEED PARAMETER.)

FSS−

(See FLIGHT SERVICE STATION.)

FUEL DUMPING− Airborne release of usable fuel.

This does not include the dropping of fuel tanks.

(See JETTISONING OF EXTERNAL STORES.)

FUEL REMAINING− A phrase used by either pilots

or controllers when relating to the fuel remaining on

board until actual fuel exhaustion. When transmitting

such information in response to either a controller

question or pilot initiated cautionary advisory to air

traffic control, pilots will state the APPROXIMATE

NUMBER OF MINUTES the flight can continue

with the fuel remaining. All reserve fuel SHOULD

BE INCLUDED in the time stated, as should an

allowance for established fuel gauge system error.

FUEL SIPHONING− Unintentional release of fuel

caused by overflow, puncture, loose cap, etc.

FUEL VENTING−

(See FUEL SIPHONING.)

FUSED TARGET-

(See DIGITAL TARGET)

FUSION [STARS/CARTS]- the combination of all

available surveillance sources (airport surveillance

radar [ASR], air route surveillance radar [ARSR],

ADS-B, etc.) into the display of a single tracked

target for air traffic control separation services.

FUSION is the equivalent of the current

single-sensor radar display. FUSION performance is

characteristic of a single-sensor radar display system.

Terminal areas use mono-pulse secondary surveil-

lance radar (ASR 9, Mode S or ASR 11, MSSR).

Pilot/Controller Glossary

10/12/17

PCG G−1

GATE HOLD PROCEDURES− Procedures at

selected airports to hold aircraft at the gate or other

ground location whenever departure delays exceed or

are anticipated to exceed 15 minutes. The sequence

for departure will be maintained in accordance with

initial call−up unless modified by flow control

restrictions. Pilots should monitor the ground

control/clearance delivery frequency for engine

start/taxi advisories or new proposed start/taxi time

if the delay changes.

GBT−

(See GROUND−BASED TRANSCEIVER.)

GCA−

(See GROUND CONTROLLED APPROACH.)

GDP−

(See GROUND DELAY PROGRAM.)

GENERAL AVIATION− That portion of civil

aviation that does not include scheduled or

unscheduled air carriers or commercial space

operations.

(See ICAO term GENERAL AVIATION.)

GENERAL AVIATION [ICAO]− All civil aviation

operations other than scheduled air services and

nonscheduled air transport operations for remunera-

tion or hire.

GEO MAP− The digitized map markings associated

with the ASR-9 Radar System.

GLIDEPATH−

(See GLIDESLOPE.)

GLIDEPATH [ICAO]− A descent profile determined

for vertical guidance during a final approach.

GLIDEPATH INTERCEPT ALTITUDE−

(See GLIDESLOPE INTERCEPT ALTITUDE.)

GLIDESLOPE− Provides vertical guidance for

aircraft during approach and landing. The glideslope/

glidepath is based on the following:

a. Electronic components emitting signals which

provide vertical guidance by reference to airborne

instruments during instrument approaches such as

ILS or

b. Visual ground aids, such as VASI, which

provide vertical guidance for a VFR approach or for

the visual portion of an instrument approach and

landing.

c. PAR. Used by ATC to inform an aircraft making

a PAR approach of its vertical position (elevation)

relative to the descent profile.

(See ICAO term GLIDEPATH.)

GLIDESLOPE INTERCEPT ALTITUDE− The

published minimum altitude to intercept the

glideslope in the intermediate segment of an

instrument approach. Government charts use the

lightning bolt symbol to identify this intercept point.

This intersection is called the Precise Final Approach

fix (PFAF). ATC directs a higher altitude, the

resultant intercept becomes the PFAF.

(See FINAL APPROACH FIX.)

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

GLOBAL NAVIGATION SATELLITE SYSTEM

(GNSS) [ICAO]− GNSS refers collectively to the

worldwide positioning, navigation, and timing

determination capability available from one or more

satellite constellation in conjunction with a network

of ground stations.

GLOBAL NAVIGATION SATELLITE SYSTEM

MINIMUM EN ROUTE IFR ALTITUDE (GNSS

MEA)− The minimum en route IFR altitude on a

published ATS route or route segment which assures

acceptable Global Navigation Satellite System

reception and meets obstacle clearance requirements.

(Refer to 14 CFR Part 91.)

(Refer to 14 CFR Part 95.)

GLOBAL POSITIONING SYSTEM (GPS)−

GPS

refers to the worldwide positioning, navigation

and timing determination capability available

from the U.S. satellite constellation. The service

provided by GPS for civil use is defined in the

GPS Standard Positioning System Performance

Standard. GPS is composed of space, control,

and user elements.

GNSS [ICAO]−

(See GLOBAL NAVIGATION SATELLITE

SYSTEM

Pilot/Controller Glossary 10/12/17

PCG G−2

GNSS MEA−

(See GLOBAL NAVIGATION SATELLITE

SYSTEM MINIMUM EN ROUTE IFR

ALTITUDE.)

GO AHEAD− Proceed with your message. Not to be

used for any other purpose.

GO AROUND− Instructions for a pilot to abandon

his/her approach to landing. Additional instructions

may follow. Unless otherwise advised by ATC, a

VFR aircraft or an aircraft conducting visual

approach should overfly the runway while climbing

to traffic pattern altitude and enter the traffic pattern

via the crosswind leg. A pilot on an IFR flight plan

making an instrument approach should execute the

published missed approach procedure or proceed as

instructed by ATC; e.g., “Go around” (additional

instructions if required).

(See LOW APPROACH.)

(See MISSED APPROACH.)

GPD−

(See GRAPHIC PLAN DISPLAY.)

GPS−

(See GLOBAL POSITIONING SYSTEM.)

GRAPHIC PLAN DISPLAY (GPD)− A view

available with EDST that provides a graphic display

of aircraft, traffic, and notification of predicted

conflicts. Graphic routes for Current Plans and Trial

Plans are displayed upon controller request.

(See EN ROUTE DECISION SUPPORT TOOL.)

GROSS NAVIGATION ERROR (GNE) − A lateral

deviation from a cleared track, normally in excess of

25 Nautical Miles (NM). More stringent standards

(for example, 10NM in some parts of the North

Atlantic region) may be used in certain regions to

support reductions in lateral separation.

GROUND BASED AUGMENTATION SYSTEM

(GBAS)– A ground based GNSS station which

provides local differential corrections, integrity

parameters and approach data via VHF data broadcast

to GNSS users to meet real-time performance

requirements for CAT I precision approaches. The

aircraft applies the broadcast data to improve the

accuracy and integrity of its GNSS signals and

computes the deviations to the selected approach. A

single ground station can serve multiple runway ends

up to an approximate radius of 23 NM.

GROUND BASED AUGMENTATION SYSTEM

(GBAS) LANDING SYSTEM (GLS)- A type of

precision IAP based on local augmentation of GNSS

data using a single GBAS station to transmit locally

corrected GNSS data, integrity parameters and

approach information. This improves the accuracy of

aircraft GNSS receivers’ signal in space, enabling the

pilot to fly a precision approach with much greater

flexibility, reliability and complexity. The GLS

procedure is published on standard IAP charts,

features the title GLS with the designated runway and

minima as low as 200 feet DA. Future plans are

expected to support Cat II and CAT III operations.

GROUND−BASED TRANSCEIVER (GBT)− The

ground−based transmitter/receiver (transceiver) re-

ceives automatic dependent surveillance−broadcast

messages, which are forwarded to an air traffic

control facility for processing and display with other

radar targets on the plan position indicator (radar

display).

(See AUTOMATIC DEPENDENT

SURVEILLANCE-BROADCAST.)

GROUND CLUTTER− A pattern produced on the

radar scope by ground returns which may degrade

other radar returns in the affected area. The effect of

ground clutter is minimized by the use of moving

target indicator (MTI) circuits in the radar equipment

resulting in a radar presentation which displays only

targets which are in motion.

(See CLUTTER.)

GROUND COMMUNICATION OUTLET (GCO)−

An unstaffed, remotely controlled, ground/ground

communications facility. Pilots at uncontrolled

airports may contact ATC and FSS via VHF to a

telephone connection to obtain an instrument

clearance or close a VFR or IFR flight plan. They may

also get an updated weather briefing prior to takeoff.

Pilots will use four “key clicks” on the VHF radio to

contact the appropriate ATC facility or six “key

clicks” to contact the FSS. The GCO system is

intended to be used only on the ground.

GROUND CONTROLLED APPROACH− A radar

approach system operated from the ground by air

traffic control personnel transmitting instructions to

the pilot by radio. The approach may be conducted

with surveillance radar (ASR) only or with both

surveillance and precision approach radar (PAR).

Usage of the term “GCA” by pilots is discouraged

except when referring to a GCA facility. Pilots should

specifically request a “PAR” approach when a

Pilot/Controller Glossary

10/12/17

PCG G−3

precision radar approach is desired or request an

“ASR” or “surveillance” approach when a nonpreci-

sion radar approach is desired.

(See RADAR APPROACH.)

GROUND DELAY PROGRAM (GDP)− A traffic

management process administered by the ATCSCC;

when aircraft are held on the ground. The purpose of

the program is to support the TM mission and limit

airborne holding. It is a flexible program and may be

implemented in various forms depending upon the

needs of the AT system. Ground delay programs

provide for equitable assignment of delays to all

system users.

GROUND SPEED− The speed of an aircraft relative

to the surface of the earth.

GROUND STOP (GS)− The GS is a process that

requires aircraft that meet a specific criteria to remain

on the ground. The criteria may be airport specific,

airspace specific, or equipment specific; for example,

all departures to San Francisco, or all departures

entering Yorktown sector, or all Category I and II

aircraft going to Charlotte. GSs normally occur with

little or no warning.

GROUND VISIBILITY−

(See VISIBILITY.)

GS−

(See GROUND STOP.)

Pilot/Controller Glossary

10/12/17

PCG H−1

HAA−

(See HEIGHT ABOVE AIRPORT.)

HAL−

(See HEIGHT ABOVE LANDING.)

HANDOFF− An action taken to transfer the radar

identification of an aircraft from one controller to

another if the aircraft will enter the receiving

controller’s airspace and radio communications with

the aircraft will be transferred.

HAR−

(See HIGH ALTITUDE REDESIGN.)

HAT−

(See HEIGHT ABOVE TOUCHDOWN.)

HAVE NUMBERS− Used by pilots to inform ATC

that they have received runway, wind, and altimeter

information only.

HAZARDOUS INFLIGHT WEATHER ADVISO-

RY SERVICE− Continuous recorded hazardous

inflight weather forecasts broadcasted to airborne

pilots over selected VOR outlets defined as an

HIWAS BROADCAST AREA.

HAZARDOUS WEATHER INFORMATION−

Summary of significant meteorological information

(SIGMET/WS), convective significant meteorologi-

cal information (convective SIGMET/WST), urgent

pilot weather reports (urgent PIREP/UUA), center

weather advisories (CWA), airmen’s meteorological

information (AIRMET/WA) and any other weather

such as isolated thunderstorms that are rapidly

developing and increasing in intensity, or low

ceilings and visibilities that are becoming wide-

spread which is considered significant and are not

included in a current hazardous weather advisory.

HEAVY (AIRCRAFT)−

(See AIRCRAFT CLASSES.)

HEIGHT ABOVE AIRPORT− The height of the

Minimum Descent Altitude above the published

airport elevation. This is published in conjunction

with circling minimums.

(See MINIMUM DESCENT ALTITUDE.)

HEIGHT ABOVE LANDING− The height above a

designated helicopter landing area used for helicopter

instrument approach procedures.

(Refer to 14 CFR Part 97.)

HEIGHT ABOVE TOUCHDOWN− The height of

the Decision Height or Minimum Descent Altitude

above the highest runway elevation in the touchdown

zone (first 3,000 feet of the runway). HAT is

published on instrument approach charts in conjunc-

tion with all straight-in minimums.

(See DECISION HEIGHT.)

(See MINIMUM DESCENT ALTITUDE.)

HELICOPTER− A heavier-than-air aircraft sup-

ported in flight chiefly by the reactions of the air on

one or more power-driven rotors on substantially

vertical axes.

HELIPAD− A small, designated area, usually with a

prepared surface, on a heliport, airport, landing/take-

off area, apron/ramp, or movement area used for

takeoff, landing, or parking of helicopters.

HELIPORT− An area of land, water, or structure used

or intended to be used for the landing and takeoff of

helicopters and includes its buildings and facilities if

any.

HELIPORT REFERENCE POINT (HRP)− The

geographic center of a heliport.

HERTZ− The standard radio equivalent of frequency

in cycles per second of an electromagnetic wave.

Kilohertz (kHz) is a frequency of one thousand cycles

per second. Megahertz (MHz) is a frequency of one

million cycles per second.

HF−

(See HIGH FREQUENCY.)

HF COMMUNICATIONS−

(See HIGH FREQUENCY COMMUNICATIONS.)

HIGH ALTITUDE REDESIGN (HAR)− A level of

non−restrictive routing (NRR) service for aircraft

that have all waypoints associated with the HAR

program in their flight management systems or

RNAV equipage.

HIGH FREQUENCY− The frequency band between

3 and 30 MHz.

(See HIGH FREQUENCY COMMUNICATIONS.)

Pilot/Controller Glossary 10/12/17

PCG H−2

HIGH FREQUENCY COMMUNICATIONS− High

radio frequencies (HF) between 3 and 30 MHz used

for air-to-ground voice communication in overseas

operations.

HIGH SPEED EXIT−

(See HIGH SPEED TAXIWAY.)

HIGH SPEED TAXIWAY− A long radius taxiway

designed and provided with lighting or marking to

define the path of aircraft, traveling at high speed (up

to 60 knots), from the runway center to a point on the

center of a taxiway. Also referred to as long radius

exit or turn-off taxiway. The high speed taxiway is

designed to expedite aircraft turning off the runway

after landing, thus reducing runway occupancy time.

HIGH SPEED TURNOFF−

(See HIGH SPEED TAXIWAY.)

HIWAS−

(See HAZARDOUS INFLIGHT WEATHER

ADVISORY SERVICE.)

HIWAS AREA−

(See HAZARDOUS INFLIGHT WEATHER

ADVISORY SERVICE.)

HIWAS BROADCAST AREA− A geographical area

of responsibility including one or more HIWAS

outlet areas assigned to a FSS for hazardous weather

advisory broadcasting.

HIWAS OUTLET AREA− An area defined as a 150

NM radius of a HIWAS outlet, expanded as necessary

to provide coverage.

HOLD FOR RELEASE− Used by ATC to delay an

aircraft for traffic management reasons; i.e., weather,

traffic volume, etc. Hold for release instructions

(including departure delay information) are used to

inform a pilot or a controller (either directly or

through an authorized relay) that an IFR departure

clearance is not valid until a release time or additional

instructions have been received.

(See ICAO term HOLDING POINT.)

HOLD IN LIEU OF PROCEDURE TURN− A hold

in lieu of procedure turn shall be established over a

final or intermediate fix when an approach can be

made from a properly aligned holding pattern. The

hold in lieu of procedure turn permits the pilot to

align with the final or intermediate segment of the

approach and/or descend in the holding pattern to an

altitude that will permit a normal descent to the final

approach fix altitude. The hold in lieu of procedure

turn is a required maneuver (the same as a procedure

turn) unless the aircraft is being radar vectored to the

final approach course, when “NoPT” is shown on the

approach chart, or when the pilot requests or the

controller advises the pilot to make a “straight−in”

approach.

HOLD PROCEDURE− A predetermined maneuver

which keeps aircraft within a specified airspace while

awaiting further clearance from air traffic control.

Also used during ground operations to keep aircraft

within a specified area or at a specified point while

awaiting further clearance from air traffic control.

(See HOLDING FIX.)

(Refer to AIM.)

HOLDING FIX− A specified fix identifiable to a

pilot by NAVAIDs or visual reference to the ground

used as a reference point in establishing and

maintaining the position of an aircraft while holding.

(See FIX.)

(See VISUAL HOLDING.)

(Refer to AIM.)

HOLDING POINT [ICAO]− A specified location,

identified by visual or other means, in the vicinity of

which the position of an aircraft in flight is

maintained in accordance with air traffic control

clearances.

HOLDING PROCEDURE−

(See HOLD PROCEDURE.)

HOLD-SHORT POINT− A point on the runway

beyond which a landing aircraft with a LAHSO

clearance is not authorized to proceed. This point

may be located prior to an intersecting runway,

taxiway, predetermined point, or approach/departure

flight path.

HOLD-SHORT POSITION LIGHTS− Flashing

in-pavement white lights located at specified

hold-short points.

HOLD-SHORT POSITION MARKING− The

painted runway marking located at the hold-short

point on all LAHSO runways.

HOLD-SHORT POSITION SIGNS− Red and white

holding position signs located alongside the

hold-short point.

Pilot/Controller Glossary

10/12/17

PCG H−3

HOMING− Flight toward a NAVAID, without

correcting for wind, by adjusting the aircraft heading

to maintain a relative bearing of zero degrees.

(See BEARING.)

(See ICAO term HOMING.)

HOMING [ICAO]− The procedure of using the

direction-finding equipment of one radio station with

the emission of another radio station, where at least

one of the stations is mobile, and whereby the mobile

station proceeds continuously towards the other

station.

HOVER CHECK− Used to describe when a

helicopter/VTOL aircraft requires a stabilized hover

to conduct a performance/power check prior to hover

taxi, air taxi, or takeoff. Altitude of the hover will

vary based on the purpose of the check.

HOVER TAXI− Used to describe a helicopter/VTOL

aircraft movement conducted above the surface and

in ground effect at airspeeds less than approximately

20 knots. The actual height may vary, and some

helicopters may require hover taxi above 25 feet AGL

to reduce ground effect turbulence or provide

clearance for cargo slingloads.

(See AIR TAXI.)

(See HOVER CHECK.)

(Refer to AIM.)

HOW DO YOU HEAR ME?− A question relating to

the quality of the transmission or to determine how

well the transmission is being received.

HZ−

(See HERTZ.)

Pilot/Controller Glossary

10/12/17

PCG I−1

I SAY AGAIN− The message will be repeated.

IAF−

(See INITIAL APPROACH FIX.)

IAP−

(See INSTRUMENT APPROACH

PROCEDURE.)

IAWP− Initial Approach Waypoint

ICAO−

(See ICAO Term INTERNATIONAL CIVIL

AVIATION ORGANIZATION.)

ICING− The accumulation of airframe ice.

Types of icing are:

a. Rime Ice− Rough, milky, opaque ice formed by

the instantaneous freezing of small supercooled

water droplets.

b. Clear Ice− A glossy, clear, or translucent ice

formed by the relatively slow freezing or large

supercooled water droplets.

c. Mixed− A mixture of clear ice and rime ice.

Intensity of icing:

a. Trace− Ice becomes perceptible. Rate of

accumulation is slightly greater than the rate of

sublimation. Deicing/anti-icing equipment is not

utilized unless encountered for an extended period of

time (over 1 hour).

b. Light− The rate of accumulation may create a

problem if flight is prolonged in this environment

(over 1 hour). Occasional use of deicing/anti-icing

equipment removes/prevents accumulation. It does

not present a problem if the deicing/anti-icing

equipment is used.

c. Moderate− The rate of accumulation is such that

even short encounters become potentially hazardous

and use of deicing/anti-icing equipment or flight

diversion is necessary.

d. Severe− The rate of ice accumulation is such

that ice protection systems fail to remove the

accumulation of ice, or ice accumulates in locations

not normally prone to icing, such as areas aft of

protected surfaces and any other areas identified by

the manufacturer. Immediate exit from the condition

is necessary.

Note:

Severe icing is aircraft dependent, as are the other

categories of icing intensity. Severe icing may

occur at any ice accumulation rate.

IDENT− A request for a pilot to activate the aircraft

transponder identification feature. This will help the

controller to confirm an aircraft identity or to identify

an aircraft.

(Refer to AIM.)

IDENT FEATURE− The special feature in the Air

Traffic Control Radar Beacon System (ATCRBS)

equipment. It is used to immediately distinguish one

displayed beacon target from other beacon targets.

(See IDENT.)

IDENTIFICATION [ICAO]− The situation which

exists when the position indication of a particular

aircraft is seen on a situation display and positively

identified.

IF−

(See INTERMEDIATE FIX.)

IFIM−

(See INTERNATIONAL FLIGHT INFORMATION

MANUAL.)

IF NO TRANSMISSION RECEIVED FOR

(TIME)− Used by ATC in radar approaches to prefix

procedures which should be followed by the pilot in

event of lost communications.

(See LOST COMMUNICATIONS.)

IFR−

(See INSTRUMENT FLIGHT RULES.)

IFR AIRCRAFT− An aircraft conducting flight in

accordance with instrument flight rules.

IFR CONDITIONS− Weather conditions below the

minimum for flight under visual flight rules.

(See INSTRUMENT METEOROLOGICAL

CONDITIONS.)

IFR DEPARTURE PROCEDURE−

(See IFR TAKEOFF MINIMUMS AND

DEPARTURE PROCEDURES.)

(Refer to AIM.)

IFR FLIGHT−

(See IFR AIRCRAFT.)

Pilot/Controller Glossary 10/12/17

PCG I−2

IFR LANDING MINIMUMS−

(See LANDING MINIMUMS.)

IFR MILITARY TRAINING ROUTES (IR)− Routes

used by the Department of Defense and associated

Reserve and Air Guard units for the purpose of

conducting low-altitude navigation and tactical

training in both IFR and VFR weather conditions

below 10,000 feet MSL at airspeeds in excess of 250

knots IAS.

IFR TAKEOFF MINIMUMS AND DEPARTURE

PROCEDURES− Title 14 Code of Federal

Regulations Part 91, prescribes standard takeoff rules

for certain civil users. At some airports, obstructions

or other factors require the establishment of

nonstandard takeoff minimums, departure proce-

dures, or both to assist pilots in avoiding obstacles

during climb to the minimum en route altitude. Those

airports are listed in FAA/DOD Instrument Approach

Procedures (IAPs) Charts under a section entitled

“IFR Takeoff Minimums and Departure Procedures.”

The FAA/DOD IAP chart legend illustrates the

symbol used to alert the pilot to nonstandard takeoff

minimums and departure procedures. When depart-

ing IFR from such airports or from any airports where

there are no departure procedures, DPs, or ATC

facilities available, pilots should advise ATC of any

departure limitations. Controllers may query a pilot

to determine acceptable departure directions, turns,

or headings after takeoff. Pilots should be familiar

with the departure procedures and must assure that

their aircraft can meet or exceed any specified climb

gradients.

IF/IAWP− Intermediate Fix/Initial Approach Way-

point. The waypoint where the final approach course

of a T approach meets the crossbar of the T. When

designated (in conjunction with a TAA) this

waypoint will be used as an IAWP when approaching

the airport from certain directions, and as an IFWP

when beginning the approach from another IAWP.

IFWP− Intermediate Fix Waypoint

ILS−

(See INSTRUMENT LANDING SYSTEM.)

ILS CATEGORIES− 1. Category I. An ILS approach

procedure which provides for approach to a height

above touchdown of not less than 200 feet and with

runway visual range of not less than 1,800 feet.−

2. Special Authorization Category I. An ILS

approach procedure which provides for approach to

a height above touchdown of not less than 150 feet

and with runway visual range of not less than 1,400

feet, HUD to DH. 3. Category II. An ILS approach

procedure which provides for approach to a height

above touchdown of not less than 100 feet and with

runway visual range of not less than 1,200 feet (with

autoland or HUD to touchdown and noted on

authorization, RVR 1,000 feet).− 4. Special

Authorization Category II with Reduced Lighting.

An ILS approach procedure which provides for

approach to a height above touchdown of not less

than 100 feet and with runway visual range of not less

than 1,200 feet with autoland or HUD to touchdown

and noted on authorization (no touchdown zone and

centerline lighting are required).− 5. Category III:

a. IIIA.−An ILS approach procedure which

provides for approach without a decision height

minimum and with runway visual range of not less

than 700 feet.

b. IIIB.−An ILS approach procedure which

provides for approach without a decision height

minimum and with runway visual range of not less

than 150 feet.

c. IIIC.−An ILS approach procedure which

provides for approach without a decision height

minimum and without runway visual range

minimum.

ILS PRM APPROACH− An instrument landing

system (ILS) approach conducted to parallel runways

whose extended centerlines are separated by less than

4,300 feet and at least 3,000 feet where independent

closely spaced approaches are permitted. Also used

in conjunction with an LDA PRM, RNAV PRM or

GLS PRM approach to conduct Simultaneous Offset

Instrument Approach (SOIA) operations. No

Transgression Zone (NTZ) monitoring is required to

conduct these approaches. ATC utilizes an enhanced

display with alerting and, with certain runway

spacing, a high update rate PRM surveillance sensor.

Use of a secondary monitor frequency, pilot PRM

training, and publication of an Attention All Users

Page are also required for all PRM approaches.

(Refer to AIM)

IM−

(See INNER MARKER.)

IMC−

(See INSTRUMENT METEOROLOGICAL

CONDITIONS.)

Pilot/Controller Glossary

10/12/17

PCG I−3

IMMEDIATELY− Used by ATC or pilots when such

action compliance is required to avoid an imminent

situation.

INCERFA (Uncertainty Phase) [ICAO]− A situation

wherein uncertainty exists as to the safety of an

aircraft and its occupants.

INCREASE SPEED TO (SPEED)−

(See SPEED ADJUSTMENT.)

INERTIAL NAVIGATION SYSTEM− An RNAV

system which is a form of self-contained navigation.

(See Area Navigation/RNAV.)

INFLIGHT REFUELING−

(See AERIAL REFUELING.)

INFLIGHT WEATHER ADVISORY−

(See WEATHER ADVISORY.)

INFORMATION REQUEST− A request originated

by an FSS for information concerning an overdue

VFR aircraft.

INITIAL APPROACH FIX− The fixes depicted on

instrument approach procedure charts that identify

the beginning of the initial approach segment(s).

(See FIX.)

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

INITIAL APPROACH SEGMENT−

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

INITIAL APPROACH SEGMENT [ICAO]− That

segment of an instrument approach procedure

between the initial approach fix and the intermediate

approach fix or, where applicable, the final approach

fix or point.

INLAND NAVIGATION FACILITY− A navigation

aid on a North American Route at which the common

route and/or the noncommon route begins or ends.

INNER MARKER− A marker beacon used with an

ILS (CAT II) precision approach located between the

middle marker and the end of the ILS runway,

transmitting a radiation pattern keyed at six dots per

second and indicating to the pilot, both aurally and

visually, that he/she is at the designated decision

height (DH), normally 100 feet above the touchdown

zone elevation, on the ILS CAT II approach. It also

marks progress during a CAT III approach.

(See INSTRUMENT LANDING SYSTEM.)

(Refer to AIM.)

INNER MARKER BEACON−

(See INNER MARKER.)

INREQ−

(See INFORMATION REQUEST.)

INS−

(See INERTIAL NAVIGATION SYSTEM.)

INSTRUMENT APPROACH−

(See INSTRUMENT APPROACH

PROCEDURE.)

INSTRUMENT APPROACH PROCEDURE− A

series of predetermined maneuvers for the orderly

transfer of an aircraft under instrument flight

conditions from the beginning of the initial approach

to a landing or to a point from which a landing may

be made visually. It is prescribed and approved for a

specific airport by competent authority.

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

a. U.S. civil standard instrument approach

procedures are approved by the FAA as prescribed

under 14 CFR Part 97 and are available for public

use.

b. U.S. military standard instrument approach

procedures are approved and published by the

Department of Defense.

c. Special instrument approach procedures are

approved by the FAA for individual operators but are

not published in 14 CFR Part 97 for public use.

(See ICAO term INSTRUMENT APPROACH

PROCEDURE.)

INSTRUMENT APPROACH OPERATIONS

[ICAO]* An approach and landing using instruments

for navigation guidance based on an instrument

approach procedure. There are two methods for

executing instrument approach operations:

a. A two−dimensional (2D) instrument approach

operation, using lateral navigation guidance only;

and

b. A three−dimensional (3D) instrument approach

operation, using both lateral and vertical navigation

guidance.

Note: Lateral and vertical navigation guidance

refers to the guidance provided either by:

a) a ground−based radio navigation aid; or

b) computer−generated navigation data from

Pilot/Controller Glossary 10/12/17

PCG I−4

ground−based, space−based, self−contained

navigation aids or a combination of these.

(See ICAO term INSTRUMENT APPROACH

PROCEDURE.)

INSTRUMENT APPROACH PROCEDURE

[ICAO]− A series of predetermined maneuvers by

reference to flight instruments with specified

protection from obstacles from the initial approach

fix, or where applicable, from the beginning of a

defined arrival route to a point from which a landing

can be completed and thereafter, if a landing is not

completed, to a position at which holding or en route

obstacle clearance criteria apply.

(See ICAO term INSTRUMENT APPROACH

OPERATIONS)

INSTRUMENT APPROACH PROCEDURES

CHARTS−

(See AERONAUTICAL CHART.)

INSTRUMENT DEPARTURE PROCEDURE

(DP)− A preplanned instrument flight rule (IFR)

departure procedure published for pilot use, in

graphic or textual format, that provides obstruction

clearance from the terminal area to the appropriate en

route structure. There are two types of DP, Obstacle

Departure Procedure (ODP), printed either textually

or graphically, and, Standard Instrument Departure

(SID), which is always printed graphically.

(See IFR TAKEOFF MINIMUMS AND

DEPARTURE PROCEDURES.)

(See OBSTACLE DEPARTURE PROCEDURES.)

(See STANDARD INSTRUMENT DEPARTURES.)

(Refer to AIM.)

INSTRUMENT DEPARTURE PROCEDURE (DP)

CHARTS−

(See AERONAUTICAL CHART.)

INSTRUMENT FLIGHT RULES− Rules governing

the procedures for conducting instrument flight. Also

a term used by pilots and controllers to indicate type

of flight plan.

(See INSTRUMENT METEOROLOGICAL

CONDITIONS.)

(See VISUAL FLIGHT RULES.)

(See VISUAL METEOROLOGICAL

CONDITIONS.)

(See ICAO term INSTRUMENT FLIGHT

RULES.)

(Refer to AIM.)

INSTRUMENT FLIGHT RULES [ICAO]− A set of

rules governing the conduct of flight under

instrument meteorological conditions.

INSTRUMENT LANDING SYSTEM− A precision

instrument approach system which normally consists

of the following electronic components and visual

aids:

a. Localizer.

(See LOCALIZER.)

b. Glideslope.

(See GLIDESLOPE.)

c. Outer Marker.

(See OUTER MARKER.)

d. Middle Marker.

(See MIDDLE MARKER.)

e. Approach Lights.

(See AIRPORT LIGHTING.)

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

INSTRUMENT METEOROLOGICAL CONDI-

TIONS− Meteorological conditions expressed in

terms of visibility, distance from cloud, and ceiling

less than the minima specified for visual meteorolog-

ical conditions.

(See INSTRUMENT FLIGHT RULES.)

(See VISUAL FLIGHT RULES.)

(See VISUAL METEOROLOGICAL

CONDITIONS.)

INSTRUMENT RUNWAY− A runway equipped

with electronic and visual navigation aids for which

a precision or nonprecision approach procedure

having straight-in landing minimums has been

approved.

(See ICAO term INSTRUMENT RUNWAY.)

INSTRUMENT RUNWAY [ICAO]− One of the

following types of runways intended for the

operation of aircraft using instrument approach

procedures:

a. Nonprecision Approach Runway−An instru-

ment runway served by visual aids and a nonvisual

aid providing at least directional guidance adequate

for a straight-in approach.

b. Precision Approach Runway, Category I−An

instrument runway served by ILS and visual aids

intended for operations down to 60 m (200 feet)

decision height and down to an RVR of the order of

800 m.

Pilot/Controller Glossary

10/12/17

PCG I−5

c. Precision Approach Runway, Category II−An

instrument runway served by ILS and visual aids

intended for operations down to 30 m (100 feet)

decision height and down to an RVR of the order of

400 m.

d. Precision Approach Runway, Category III−An

instrument runway served by ILS to and along the

surface of the runway and:

1. Intended for operations down to an RVR of

the order of 200 m (no decision height being

applicable) using visual aids during the final phase of

landing;

2. Intended for operations down to an RVR of

the order of 50 m (no decision height being

applicable) using visual aids for taxiing;

3. Intended for operations without reliance on

visual reference for landing or taxiing.

Note 1: See Annex 10 Volume I, Part I, Chapter 3,

for related ILS specifications.

Note 2: Visual aids need not necessarily be

matched to the scale of nonvisual aids provided.

The criterion for the selection of visual aids is the

conditions in which operations are intended to be

conducted.

INTEGRITY− The ability of a system to provide

timely warnings to users when the system should not

be used for navigation.

INTERMEDIATE APPROACH SEGMENT−

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

INTERMEDIATE APPROACH SEGMENT

[ICAO]− That segment of an instrument approach

procedure between either the intermediate approach

fix and the final approach fix or point, or between the

end of a reversal, race track or dead reckoning track

procedure and the final approach fix or point, as

appropriate.

INTERMEDIATE FIX− The fix that identifies the

beginning of the intermediate approach segment of an

instrument approach procedure. The fix is not

normally identified on the instrument approach chart

as an intermediate fix (IF).

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

INTERMEDIATE LANDING− On the rare occasion

that this option is requested, it should be approved.

The departure center, however, must advise the

ATCSCC so that the appropriate delay is carried over

and assigned at the intermediate airport. An

intermediate landing airport within the arrival center

will not be accepted without coordination with and

the approval of the ATCSCC.

INTERNATIONAL AIRPORT− Relating to interna-

tional flight, it means:

a. An airport of entry which has been designated

by the Secretary of Treasury or Commissioner of

Customs as an international airport for customs

service.

b. A landing rights airport at which specific

permission to land must be obtained from customs

authorities in advance of contemplated use.

c. Airports designated under the Convention on

International Civil Aviation as an airport for use by

international commercial air transport and/or interna-

tional general aviation.

(See ICAO term INTERNATIONAL AIRPORT.)

(Refer to Chart Supplement U.S.)

(Refer to IFIM.)

INTERNATIONAL AIRPORT [ICAO]− Any airport

designated by the Contracting State in whose

territory it is situated as an airport of entry and

departure for international air traffic, where the

formalities incident to customs, immigration, public

health, animal and plant quarantine and similar

procedures are carried out.

INTERNATIONAL CIVIL AVIATION ORGA-

NIZATION [ICAO]− A specialized agency of the

United Nations whose objective is to develop the

principles and techniques of international air

navigation and to foster planning and development of

international civil air transport.

a. Regions include:

1. African-Indian Ocean Region

2. Caribbean Region

3. European Region

4. Middle East/Asia Region

5. North American Region

6. North Atlantic Region

7. Pacific Region

8. South American Region

INTERNATIONAL FLIGHT INFORMATION

MANUAL− A publication designed primarily as a

pilot’s preflight planning guide for flights into

foreign airspace and for flights returning to the U.S.

from foreign locations.

Pilot/Controller Glossary 10/12/17

PCG I−6

INTERROGATOR− The ground-based surveillance

radar beacon transmitter-receiver, which normally

scans in synchronism with a primary radar,

transmitting discrete radio signals which repetitious-

ly request all transponders on the mode being used to

reply. The replies received are mixed with the

primary radar returns and displayed on the same plan

position indicator (radar scope). Also, applied to the

airborne element of the TACAN/DME system.

(See TRANSPONDER.)

(Refer to AIM.)

INTERSECTING RUNWAYS− Two or more

runways which cross or meet within their lengths.

(See INTERSECTION.)

INTERSECTION−

a. A point defined by any combination of courses,

radials, or bearings of two or more navigational aids.

b. Used to describe the point where two runways,

a runway and a taxiway, or two taxiways cross or

meet.

INTERSECTION DEPARTURE− A departure from

any runway intersection except the end of the runway.

(See INTERSECTION.)

INTERSECTION TAKEOFF−

(See INTERSECTION DEPARTURE.)

IR−

(See IFR MILITARY TRAINING ROUTES.)

IRREGULAR SURFACE− A surface that is open for

use but not per regulations.

ISR– Indicates the confidence level of the track

requires 5NM separation. 3NM separation, 1 1/2NM

separation, and target resolution cannot be used.

Pilot/Controller Glossary

10/12/17

PCG J−1

JAMMING− Electronic or mechanical interference

which may disrupt the display of aircraft on radar or

the transmission/reception of radio communications/

navigation.

JET BLAST− Jet engine exhaust (thrust stream

turbulence).

(See WAKE TURBULENCE.)

JET ROUTE− A route designed to serve aircraft

operations from 18,000 feet MSL up to and including

flight level 450. The routes are referred to as “J”

routes with numbering to identify the designated

route; e.g., J105.

(See Class A AIRSPACE.)

(Refer to 14 CFR Part 71.)

JET STREAM− A migrating stream of high-speed

winds present at high altitudes.

JETTISONING OF EXTERNAL STORES− Air-

borne release of external stores; e.g., tiptanks,

ordnance.

(See FUEL DUMPING.)

(Refer to 14 CFR Part 91.)

JOINT USE RESTRICTED AREA−

(See RESTRICTED AREA.)

JUMP ZONE− The airspace directly associated with

a Drop Zone. Vertical and horizontal limits may be

locally defined.

Pilot/Controller Glossary

10/12/17

PCG K−1

KNOWN TRAFFIC− With respect to ATC clear-

ances, means aircraft whose altitude, position, and

intentions are known to ATC.

Pilot/Controller Glossary

10/12/17

PCG L−1

LAA−

(See LOCAL AIRPORT ADVISORY.)

LAAS−

(See LOW ALTITUDE ALERT SYSTEM.)

LAHSO− An acronym for “Land and Hold Short

Operation.” These operations include landing and

holding short of an intersecting runway, a taxiway, a

predetermined point, or an approach/departure

flightpath.

LAHSO-DRY− Land and hold short operations on

runways that are dry.

LAHSO-WET− Land and hold short operations on

runways that are wet (but not contaminated).

LAND AND HOLD SHORT OPERATIONS−

Operations which include simultaneous takeoffs and

landings and/or simultaneous landings when a

landing aircraft is able and is instructed by the

controller to hold-short of the intersecting runway/

taxiway or designated hold-short point. Pilots are

expected to promptly inform the controller if the hold

short clearance cannot be accepted.

(See PARALLEL RUNWAYS.)

(Refer to AIM.)

LANDING AREA− Any locality either on land,

water, or structures, including airports/heliports and

intermediate landing fields, which is used, or

intended to be used, for the landing and takeoff of

aircraft whether or not facilities are provided for the

shelter, servicing, or for receiving or discharging

passengers or cargo.

(See ICAO term LANDING AREA.)

LANDING AREA [ICAO]− That part of a movement

area intended for the landing or take-off of aircraft.

LANDING DIRECTION INDICATOR− A device

which visually indicates the direction in which

landings and takeoffs should be made.

(See TETRAHEDRON.)

(Refer to AIM.)

LANDING DISTANCE AVAILABLE (LDA)− The

runway length declared available and suitable for a

landing airplane.

(See ICAO term LANDING DISTANCE

AVAILABLE.)

LANDING DISTANCE AVAILABLE [ICAO]− The

length of runway which is declared available and

suitable for the ground run of an aeroplane landing.

LANDING MINIMUMS− The minimum visibility

prescribed for landing a civil aircraft while using an

instrument approach procedure. The minimum

applies with other limitations set forth in 14 CFR

Part 91 with respect to the Minimum Descent

Altitude (MDA) or Decision Height (DH) prescribed

in the instrument approach procedures as follows:

a. Straight-in landing minimums. A statement of

MDA and visibility, or DH and visibility, required for

a straight-in landing on a specified runway, or

b. Circling minimums. A statement of MDA and

visibility required for the circle-to-land maneuver.

Note: Descent below the MDA or DH must meet the

conditions stated in 14 CFR Section 91.175.

(See CIRCLE-TO-LAND MANEUVER.)

(See DECISION HEIGHT.)

(See INSTRUMENT APPROACH

PROCEDURE.)

(See MINIMUM DESCENT ALTITUDE.)

(See STRAIGHT-IN LANDING.)

(See VISIBILITY.)

(Refer to 14 CFR Part 91.)

LANDING ROLL− The distance from the point of

touchdown to the point where the aircraft can be

brought to a stop or exit the runway.

LANDING SEQUENCE− The order in which

aircraft are positioned for landing.

(See APPROACH SEQUENCE.)

LAST ASSIGNED ALTITUDE− The last altitude/

flight level assigned by ATC and acknowledged by

the pilot.

(See MAINTAIN.)

(Refer to 14 CFR Part 91.)

LATERAL NAVIGATION (LNAV)– A function of

area navigation (RNAV) equipment which calculates,

Pilot/Controller Glossary 10/12/17

PCG L−2

displays, and provides lateral guidance to a profile or

path.

LATERAL SEPARATION− The lateral spacing of

aircraft at the same altitude by requiring operation on

different routes or in different geographical locations.

(See SEPARATION.)

LDA−

(See LOCALIZER TYPE DIRECTIONAL AID.)

(See LANDING DISTANCE AVAILABLE.)

(See ICAO Term LANDING DISTANCE

AVAILABLE.)

LF−

(See LOW FREQUENCY.)

LIGHTED AIRPORT− An airport where runway and

obstruction lighting is available.

(See AIRPORT LIGHTING.)

(Refer to AIM.)

LIGHT GUN− A handheld directional light signaling

device which emits a brilliant narrow beam of white,

green, or red light as selected by the tower controller.

The color and type of light transmitted can be used to

approve or disapprove anticipated pilot actions where

radio communication is not available. The light gun

is used for controlling traffic operating in the vicinity

of the airport and on the airport movement area.

(Refer to AIM.)

LIGHT-SPORT AIRCRAFT (LSA)- An

FAA-registered aircraft, other than a helicopter or

powered-lift, that meets certain weight and

performance. Principally it is a single engine aircraft

with a maximum of two seats and weighing no more

than 1,430 pounds if intended for operation on water,

or 1,320 pounds if not. They must be of simple design

(fixed landing gear (except if intended for operations

on water or a glider) piston powered,

non-pressurized, with a fixed or ground adjustable

propeller), Performance is also limited to a maximum

airspeed in level flight of not more than 120 knots

CAS, have a maximum never-exceed speed of not

more than 120 knots CAS for a glider, and have a

maximum stalling speed, without the use of

lift-enhancing devices (VS1 ) of not more than

45 knots CAS. They may be certificated as either

Experimental LSA or as a Special LSA aircraft. A

minimum of a sport pilot

certificate is required to

operate light-sport aircraft.” (Refer to 14 CFR Part 1,

§1.1.)

LINE UP AND WAIT (LUAW)− Used by ATC to

inform a pilot to taxi onto the departure runway to line

up and wait. It is not authorization for takeoff. It is

used when takeoff clearance cannot immediately be

issued because of traffic or other reasons.

(See CLEARED FOR TAKEOFF.)

LOCAL AIRPORT ADVISORY (LAA)− A service

available only in Alaska and provided by facilities,

which are located on the landing airport, have a

discrete ground−to−air communication frequency or

the tower frequency when the tower is closed,

automated weather reporting with voice broadcast-

ing, and a continuous ASOS/AWSS/AWOS data

display, other continuous direct reading instruments,

or manual observations available to the specialist.

(See AIRPORT ADVISORY AREA.)

LOCAL TRAFFIC− Aircraft operating in the traffic

pattern or within sight of the tower, or aircraft known

to be departing or arriving from flight in local practice

areas, or aircraft executing practice instrument

approaches at the airport.

(See TRAFFIC PATTERN.)

LOCALIZER− The component of an ILS which

provides course guidance to the runway.

(See INSTRUMENT LANDING SYSTEM.)

(See ICAO term LOCALIZER COURSE.)

(Refer to AIM.)

LOCALIZER COURSE [ICAO]− The locus of

points, in any given horizontal plane, at which the

DDM (difference in depth of modulation) is zero.

LOCALIZER OFFSET− An angular offset of the

localizer aligned with 3_ of the runway alignment.

LOCALIZER TYPE DIRECTIONAL AID− A

localizer with an angular offset that exceeds 3_. of the

runway alignment used for nonprecision instrument

approaches with utility and accuracy comparable to

a localizer but which are not part of a complete ILS.

(Refer to AIM.)

LOCALIZER TYPE DIRECTIONAL AID (LDA)

PRECISION RUNWAY MONITOR (PRM)

APPROACH− An approach, which includes a

glidslope, used in conjunction with an ILS PRM,

RNAV PRM or GLS PRM approach to an adjacent

runway to conduct Simultaneous Offset Instrument

Approaches (SOIA) to parallel runways whose

centerlines are separated by less than 3,000 feet and

Pilot/Controller Glossary

10/12/17

PCG L−3

at least 750 feet. NTZ monitoring is required to

conduct these approaches.

(See SIMULTANEOUS OFFSET INSTRUMENT

APPROACH (SOIA).)

(Refer to AIM)

LOCALIZER USABLE DISTANCE− The maxi-

mum distance from the localizer transmitter at a

specified altitude, as verified by flight inspection, at

which reliable course information is continuously

received.

(Refer to AIM.)

LOCATOR [ICAO]− An LM/MF NDB used as an aid

to final approach.

Note: A locator usually has an average radius of

rated coverage of between 18.5 and 46.3 km (10

and 25 NM).

LONG RANGE NAVIGATION−

(See LORAN.)

LONGITUDINAL SEPARATION− The longitudi-

nal spacing of aircraft at the same altitude by a

minimum distance expressed in units of time or

miles.

(See SEPARATION.)

(Refer to AIM.)

LORAN− An electronic navigational system by

which hyperbolic lines of position are determined by

measuring the difference in the time of reception of

synchronized pulse signals from two fixed transmit-

ters. Loran A operates in the 1750-1950 kHz

frequency band. Loran C and D operate in the

100-110 kHz frequency band. In 2010, the U.S. Coast

Guard terminated all U.S. LORAN-C transmissions.

(Refer to AIM.)

LOST COMMUNICATIONS− Loss of the ability to

communicate by radio. Aircraft are sometimes

referred to as NORDO (No Radio). Standard pilot

procedures are specified in 14 CFR Part 91. Radar

controllers issue procedures for pilots to follow in the

event of lost communications during a radar approach

when weather reports indicate that an aircraft will

likely encounter IFR weather conditions during the

approach.

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

LOST LINK− An interruption or loss of the control

link, or when the pilot is unable to effect control of the

aircraft and, as a result, the UA will perform a

predictable or planned maneuver. Loss of command

and control link between the Control Station and the

aircraft. There are two types of links:

a. An uplink which transmits command instruc-

tions to the aircraft, and

b. A downlink which transmits the status of the

aircraft and provides situational awareness to the

pilot.

LOST LINK PROCEDURE− Preprogrammed or

predetermined mitigations to ensure the continued

safe operation of the UA in the event of a lost link

(LL). In the event positive link cannot be established,

flight termination must be implemented.

LOW ALTITUDE AIRWAY STRUCTURE− The

network of airways serving aircraft operations up to

but not including 18,000 feet MSL.

(See AIRWAY.)

(Refer to AIM.)

LOW ALTITUDE ALERT, CHECK YOUR ALTI-

TUDE IMMEDIATELY−

(See SAFETY ALERT.)

LOW APPROACH− An approach over an airport or

runway following an instrument approach or a VFR

approach including the go-around maneuver where

the pilot intentionally does not make contact with the

runway.

(Refer to AIM.)

LOW FREQUENCY− The frequency band between

30 and 300 kHz.

(Refer to AIM.)

LPV− A type of approach with vertical guidance

(APV) based on WAAS, published on RNAV (GPS)

approach charts. This procedure takes advantage of

the precise lateral guidance available from WAAS.

The minima is published as a decision altitude (DA).

LUAW−

(See LINE UP AND WAIT.)

Pilot/Controller Glossary

10/12/17

PCG M−1

MAA−

(See MAXIMUM AUTHORIZED ALTITUDE.)

MACH NUMBER− The ratio of true airspeed to the

speed of sound; e.g., MACH .82, MACH 1.6.

(See AIRSPEED.)

MACH TECHNIQUE [ICAO]− Describes a control

technique used by air traffic control whereby turbojet

aircraft operating successively along suitable routes

are cleared to maintain appropriate MACH numbers

for a relevant portion of the en route phase of flight.

The principle objective is to achieve improved

utilization of the airspace and to ensure that

separation between successive aircraft does not

decrease below the established minima.

MAHWP− Missed Approach Holding Waypoint

MAINTAIN−

a. Concerning altitude/flight level, the term

means to remain at the altitude/flight level specified.

The phrase “climb and” or “descend and” normally

precedes “maintain” and the altitude assignment;

e.g., “descend and maintain 5,000.”

b. Concerning other ATC instructions, the term is

used in its literal sense; e.g., maintain VFR.

MAINTENANCE PLANNING FRICTION

LEVEL− The friction level specified in

AC 150/5320-12, Measurement, Construction, and

Maintenance of Skid Resistant Airport Pavement

Surfaces, which represents the friction value below

which the runway pavement surface remains

acceptable for any category or class of aircraft

operations but which is beginning to show signs of

deterioration. This value will vary depending on the

particular friction measurement equipment used.

MAKE SHORT APPROACH− Used by ATC to

inform a pilot to alter his/her traffic pattern so as to

make a short final approach.

(See TRAFFIC PATTERN.)

MAN PORTABLE AIR DEFENSE SYSTEMS

(MANPADS)− MANPADS are lightweight, shoul-

der−launched, missile systems used to bring down

aircraft and create mass casualties. The potential for

MANPADS use against airborne aircraft is real and

requires familiarity with the subject. Terrorists

choose MANPADS because the weapons are low

cost, highly mobile, require minimal set−up time, and

are easy to use and maintain. Although the weapons

have limited range, and their accuracy is affected by

poor visibility and adverse weather, they can be fired

from anywhere on land or from boats where there is

unrestricted visibility to the target.

MANDATORY ALTITUDE− An altitude depicted

on an instrument Approach Procedure Chart

requiring the aircraft to maintain altitude at the

depicted value.

MANPADS−

(See MAN PORTABLE AIR DEFENSE

SYSTEMS.)

MAP−

(See MISSED APPROACH POINT.)

MARKER BEACON− An electronic navigation

facility transmitting a 75 MHz vertical fan or

boneshaped radiation pattern. Marker beacons are

identified by their modulation frequency and keying

code, and when received by compatible airborne

equipment, indicate to the pilot, both aurally and

visually, that he/she is passing over the facility.

(See INNER MARKER.)

(See MIDDLE MARKER.)

(See OUTER MARKER.)

(Refer to AIM.)

MARSA−

(See MILITARY AUTHORITY ASSUMES

RESPONSIBILITY FOR SEPARATION OF

AIRCRAFT.)

MAWP− Missed Approach Waypoint

MAXIMUM AUTHORIZED ALTITUDE− A pub-

lished altitude representing the maximum usable

altitude or flight level for an airspace structure or

route segment. It is the highest altitude on a Federal

airway, jet route, area navigation low or high route,

or other direct route for which an MEA is designated

in 14 CFR Part 95 at which adequate reception of

navigation aid signals is assured.

MAYDAY− The international radiotelephony distress

signal. When repeated three times, it indicates

Pilot/Controller Glossary 10/12/17

PCG M−2

imminent and grave danger and that immediate

assistance is requested.

(See PAN-PAN.)

(Refer to AIM.)

MCA−

(See MINIMUM CROSSING ALTITUDE.)

MDA−

(See MINIMUM DESCENT ALTITUDE.)

MEA−

(See MINIMUM EN ROUTE IFR ALTITUDE.)

MEARTS−

(See MICRO-EN ROUTE AUTOMATED RADAR

TRACKING SYSTEM.)

METEOROLOGICAL IMPACT STATEMENT−

An unscheduled planning forecast describing

conditions expected to begin within 4 to 12 hours

which may impact the flow of air traffic in a specific

center’s (ARTCC) area.

METER FIX ARC− A semicircle, equidistant from

a meter fix, usually in low altitude relatively close to

the meter fix, used to help CTAS/HOST calculate a

meter time, and determine appropriate sector meter

list assignments for aircraft not on an established

arrival route or assigned a meter fix.

METER FIX TIME/SLOT TIME− A calculated time

to depart the meter fix in order to cross the vertex at

the ACLT. This time reflects descent speed

adjustment and any applicable time that must be

absorbed prior to crossing the meter fix.

METER LIST−

(See ARRIVAL SECTOR ADVISORY LIST.)

METER LIST DISPLAY INTERVAL− A dynamic

parameter which controls the number of minutes

prior to the flight plan calculated time of arrival at the

meter fix for each aircraft, at which time the TCLT is

frozen and becomes an ACLT; i.e., the VTA is

updated and consequently the TCLT modified as

appropriate until frozen at which time updating is

suspended and an ACLT is assigned. When frozen,

the flight entry is inserted into the arrival sector’s

meter list for display on the sector PVD/MDM.

MLDI is used if filed true airspeed is less than or

equal to freeze speed parameters (FSPD).

METERING− A method of time-regulating arrival

traffic flow into a terminal area so as not to exceed a

predetermined terminal acceptance rate.

METERING AIRPORTS− Airports adapted for

metering and for which optimum flight paths are

defined. A maximum of 15 airports may be adapted.

METERING FIX− A fix along an established route

from over which aircraft will be metered prior to

entering terminal airspace. Normally, this fix should

be established at a distance from the airport which

will facilitate a profile descent 10,000 feet above

airport elevation (AAE) or above.

METERING POSITION(S)− Adapted PVDs/

MDMs and associated “D” positions eligible for

display of a metering position list. A maximum of

four PVDs/MDMs may be adapted.

METERING POSITION LIST− An ordered list of

data on arrivals for a selected metering airport

displayed on a metering position PVD/MDM.

MFT−

(See METER FIX TIME/SLOT TIME.)

MHA−

(See MINIMUM HOLDING ALTITUDE.)

MIA−

(See MINIMUM IFR ALTITUDES.)

MICROBURST− A small downburst with outbursts

of damaging winds extending 2.5 miles or less. In

spite of its small horizontal scale, an intense

microburst could induce wind speeds as high as 150

knots

(Refer to AIM.)

MICRO-EN ROUTE AUTOMATED RADAR

TRACKING SYSTEM (MEARTS)− An automated

radar and radar beacon tracking system capable of

employing both short-range (ASR) and long-range

(ARSR) radars. This microcomputer driven system

provides improved tracking, continuous data record-

ing, and use of full digital radar displays.

MID RVR−

(See VISIBILITY.)

MIDDLE COMPASS LOCATOR−

(See COMPASS LOCATOR.)

MIDDLE MARKER− A marker beacon that defines

a point along the glideslope of an ILS normally

located at or near the point of decision height (ILS

Category I). It is keyed to transmit alternate dots and

dashes, with the alternate dots and dashes keyed at the

rate of 95 dot/dash combinations per minute on a

Pilot/Controller Glossary

10/12/17

PCG M−3

1300 Hz tone, which is received aurally and visually

by compatible airborne equipment.

(See INSTRUMENT LANDING SYSTEM.)

(See MARKER BEACON.)

(Refer to AIM.)

MILES-IN-TRAIL− A specified distance between

aircraft, normally, in the same stratum associated

with the same destination or route of flight.

MILITARY AUTHORITY ASSUMES RESPONSI-

BILITY FOR SEPARATION OF AIRCRAFT− A

condition whereby the military services involved

assume responsibility for separation between

participating military aircraft in the ATC system. It is

used only for required IFR operations which are

specified in letters of agreement or other appropriate

FAA or military documents.

MILITARY LANDING ZONE− A landing strip used

exclusively by the military for training. A military

landing zone does not carry a runway designation.

MILITARY OPERATIONS AREA−

(See SPECIAL USE AIRSPACE.)

MILITARY TRAINING ROUTES− Airspace of

defined vertical and lateral dimensions established

for the conduct of military flight training at airspeeds

in excess of 250 knots IAS.

(See IFR MILITARY TRAINING ROUTES.)

(See VFR MILITARY TRAINING ROUTES.)

MINIMA−

(See MINIMUMS.)

MINIMUM CROSSING ALTITUDE− The lowest

altitude at certain fixes at which an aircraft must cross

when proceeding in the direction of a higher

minimum en route IFR altitude (MEA).

(See MINIMUM EN ROUTE IFR ALTITUDE.)

MINIMUM DESCENT ALTITUDE− The lowest

altitude, expressed in feet above mean sea level, to

which descent is authorized on final approach or

during circle-to-land maneuvering in execution of a

standard instrument approach procedure where no

electronic glideslope is provided.

(See NONPRECISION APPROACH

PROCEDURE.)

MINIMUM EN ROUTE IFR ALTITUDE (MEA)−

The lowest published altitude between radio fixes

which assures acceptable navigational signal cover-

age and meets obstacle clearance requirements

between those fixes. The MEA prescribed for a

Federal airway or segment thereof, area navigation

low or high route, or other direct route applies to the

entire width of the airway, segment, or route between

the radio fixes defining the airway, segment, or route.

(Refer to 14 CFR Part 91.)

(Refer to 14 CFR Part 95.)

(Refer to AIM.)

MINIMUM FRICTION LEVEL− The friction level

specified in AC 150/5320-12, Measurement,

Construction, and Maintenance of Skid Resistant

Airport Pavement Surfaces, that represents the

minimum recommended wet pavement surface

friction value for any turbojet aircraft engaged in

LAHSO. This value will vary with the particular

friction measurement equipment used.

MINIMUM FUEL− Indicates that an aircraft’s fuel

supply has reached a state where, upon reaching the

destination, it can accept little or no delay. This is not

an emergency situation but merely indicates an

emergency situation is possible should any undue

delay occur.

(Refer to AIM.)

MINIMUM HOLDING ALTITUDE− The lowest

altitude prescribed for a holding pattern which

assures navigational signal coverage, communica-

tions, and meets obstacle clearance requirements.

MINIMUM IFR ALTITUDES (MIA)− Minimum

altitudes for IFR operations as prescribed in 14 CFR

Part 91. These altitudes are published on aeronautical

charts and prescribed in 14 CFR Part 95 for airways

and routes, and in 14 CFR Part 97 for standard

instrument approach procedures. If no applicable

minimum altitude is prescribed in 14 CFR Part 95 or

14 CFR Part 97, the following minimum IFR

altitude applies:

a. In designated mountainous areas, 2,000 feet

above the highest obstacle within a horizontal

distance of 4 nautical miles from the course to be

flown; or

b. Other than mountainous areas, 1,000 feet above

the highest obstacle within a horizontal distance of 4

nautical miles from the course to be flown; or

Pilot/Controller Glossary 10/12/17

PCG M−4

c. As otherwise authorized by the Administrator

or assigned by ATC.

(See MINIMUM CROSSING ALTITUDE.)

(See MINIMUM EN ROUTE IFR ALTITUDE.)

(See MINIMUM OBSTRUCTION CLEARANCE

ALTITUDE.)

(See MINIMUM SAFE ALTITUDE.)

(See MINIMUM VECTORING ALTITUDE.)

(Refer to 14 CFR Part 91.)

MINIMUM OBSTRUCTION CLEARANCE ALTI-

TUDE (MOCA)− The lowest published altitude in

effect between radio fixes on VOR airways,

off-airway routes, or route segments which meets

obstacle clearance requirements for the entire route

segment and which assures acceptable navigational

signal coverage only within 25 statute (22 nautical)

miles of a VOR.

(Refer to 14 CFR Part 91.)

(Refer to 14 CFR Part 95.)

MINIMUM RECEPTION ALTITUDE− The lowest

altitude at which an intersection can be determined.

(Refer to 14 CFR Part 95.)

MINIMUM SAFE ALTITUDE−

a. The minimum altitude specified in 14 CFR

Part 91 for various aircraft operations.

b. Altitudes depicted on approach charts which

provide at least 1,000 feet of obstacle clearance for

emergency use. These altitudes will be identified as

Minimum Safe Altitudes or Emergency Safe

Altitudes and are established as follows:

1. Minimum Safe Altitude (MSA). Altitudes

depicted on approach charts which provide at least

1,000 feet of obstacle clearance within a 25-mile

radius of the navigation facility, waypoint, or airport

reference point upon which the MSA is predicated.

MSAs are for emergency use only and do not

necessarily assure acceptable navigational signal

coverage.

(See ICAO term Minimum Sector Altitude.)

2. Emergency Safe Altitude (ESA). Altitudes

depicted on approach charts which provide at least

1,000 feet of obstacle clearance in nonmountainous

areas and 2,000 feet of obstacle clearance in

designated mountainous areas within a 100-mile

radius of the navigation facility or waypoint used as

the ESA center. These altitudes are normally used

only in military procedures and are identified on

published procedures as “Emergency Safe

Altitudes.”

MINIMUM SAFE ALTITUDE WARNING− A

function of the ARTS III computer that aids the

controller by alerting him/her when a tracked Mode

C equipped aircraft is below or is predicted by the

computer to go below a predetermined minimum safe

altitude.

(Refer to AIM.)

MINIMUM SECTOR ALTITUDE [ICAO]− The

lowest altitude which may be used under emergency

conditions which will provide a minimum clearance

of 300 m (1,000 feet) above all obstacles located in

an area contained within a sector of a circle of 46 km

(25 NM) radius centered on a radio aid to navigation.

MINIMUMS− Weather condition requirements

established for a particular operation or type of

operation; e.g., IFR takeoff or landing, alternate

airport for IFR flight plans, VFR flight, etc.

(See IFR CONDITIONS.)

(See IFR TAKEOFF MINIMUMS AND

DEPARTURE PROCEDURES.)

(See LANDING MINIMUMS.)

(See VFR CONDITIONS.)

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

MINIMUM VECTORING ALTITUDE (MVA)−

The lowest MSL altitude at which an IFR aircraft will

be vectored by a radar controller, except as otherwise

authorized for radar approaches, departures, and

missed approaches. The altitude meets IFR obstacle

clearance criteria. It may be lower than the published

MEA along an airway or J-route segment. It may be

utilized for radar vectoring only upon the controller’s

determination that an adequate radar return is being

received from the aircraft being controlled. Charts

depicting minimum vectoring altitudes are normally

available only to the controllers and not to pilots.

(Refer to AIM.)

MINUTES-IN-TRAIL− A specified interval be-

tween aircraft expressed in time. This method would

more likely be utilized regardless of altitude.

MIS−

(See METEOROLOGICAL IMPACT

STATEMENT.)

MISSED APPROACH−

a. A maneuver conducted by a pilot when an

instrument approach cannot be completed to a

Pilot/Controller Glossary

10/12/17

PCG M−5

landing. The route of flight and altitude are shown on

instrument approach procedure charts. A pilot

executing a missed approach prior to the Missed

Approach Point (MAP) must continue along the final

approach to the MAP.

b. A term used by the pilot to inform ATC that

he/she is executing the missed approach.

c. At locations where ATC radar service is

provided, the pilot should conform to radar vectors

when provided by ATC in lieu of the published

missed approach procedure.

(See MISSED APPROACH POINT.)

(Refer to AIM.)

MISSED APPROACH POINT− A point prescribed

in each instrument approach procedure at which a

missed approach procedure shall be executed if the

required visual reference does not exist.

(See MISSED APPROACH.)

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

MISSED APPROACH PROCEDURE [ICAO]− The

procedure to be followed if the approach cannot be

continued.

MISSED APPROACH SEGMENT−

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

MLDI−

(See METER LIST DISPLAY INTERVAL.)

MM−

(See MIDDLE MARKER.)

MOA−

(See MILITARY OPERATIONS AREA.)

MOCA−

(See MINIMUM OBSTRUCTION CLEARANCE

ALTITUDE.)

MODE− The letter or number assigned to a specific

pulse spacing of radio signals transmitted or received

by ground interrogator or airborne transponder

components of the Air Traffic Control Radar Beacon

System (ATCRBS). Mode A (military Mode 3) and

Mode C (altitude reporting) are used in air traffic

control.

(See INTERROGATOR.)

(See RADAR.)

(See TRANSPONDER.)

(See ICAO term MODE.)

(Refer to AIM.)

MODE (SSR MODE) [ICAO]− The letter or number

assigned to a specific pulse spacing of the

interrogation signals transmitted by an interrogator.

There are 4 modes, A, B, C and D specified in Annex

10, corresponding to four different interrogation

pulse spacings.

MODE C INTRUDER ALERT− A function of

certain air traffic control automated systems designed

to alert radar controllers to existing or pending

situations between a tracked target (known IFR or

VFR aircraft) and an untracked target (unknown IFR

or VFR aircraft) that requires immediate attention/

action.

(See CONFLICT ALERT.)

MODEL AIRCRAFT− An unmanned aircraft that is:

(1) capable of sustained flight in the atmosphere; (2)

flown within visual line of sight of the person

operating the aircraft; and (3) flown for hobby or

recreational purposes.

MONITOR− (When used with communication

transfer) listen on a specific frequency and stand by

for instructions. Under normal circumstances do not

establish communications.

MONITOR ALERT (MA)− A function of the TFMS

that provides traffic management personnel with a

tool for predicting potential capacity problems in

individual operational sectors. The MA is an

indication that traffic management personnel need to

analyze a particular sector for actual activity and to

determine the required action(s), if any, needed to

control the demand.

MONITOR ALERT PARAMETER (MAP)− The

number designated for use in monitor alert

processing by the TFMS. The MAP is designated for

each operational sector for increments of 15 minutes.

MOSAIC/MULTI−SENSOR MODE− Accepts posi-

tional data from multiple radar or ADS−B sites.

Targets are displayed from a single source within a

radar sort box according to the hierarchy of the

sources assigned.

Pilot/Controller Glossary 10/12/17

PCG M−6

MOVEMENT AREA− The runways, taxiways, and

other areas of an airport/heliport which are utilized

for taxiing/hover taxiing, air taxiing, takeoff, and

landing of aircraft, exclusive of loading ramps and

parking areas. At those airports/heliports with a

tower, specific approval for entry onto the movement

area must be obtained from ATC.

(See ICAO term MOVEMENT AREA.)

MOVEMENT AREA [ICAO]− That part of an

aerodrome to be used for the takeoff, landing and

taxiing of aircraft, consisting of the maneuvering area

and the apron(s).

MOVING TARGET INDICATOR− An electronic

device which will permit radar scope presentation

only from targets which are in motion. A partial

remedy for ground clutter.

MRA−

(See MINIMUM RECEPTION ALTITUDE.)

MSA−

(See MINIMUM SAFE ALTITUDE.)

MSAW−

(See MINIMUM SAFE ALTITUDE WARNING.)

MTI−

(See MOVING TARGET INDICATOR.)

MTR−

(See MILITARY TRAINING ROUTES.)

MULTICOM− A mobile service not open to public

correspondence used to provide communications

essential to conduct the activities being performed by

or directed from private aircraft.

MULTIPLE RUNWAYS− The utilization of a

dedicated arrival runway(s) for departures and a

dedicated departure runway(s) for arrivals when

feasible to reduce delays and enhance capacity.

MVA−

(See MINIMUM VECTORING ALTITUDE.)

Pilot/Controller Glossary

10/12/17

PCG N−1

NAS−

(See NATIONAL AIRSPACE SYSTEM.)

NAT HLA –

(See NORTH ATLANTIC HIGH LEVEL

AIRSPACE)

NATIONAL AIRSPACE SYSTEM− The common

network of U.S. airspace; air navigation facilities,

equipment and services, airports or landing areas;

aeronautical charts, information and services; rules,

regulations and procedures, technical information,

and manpower and material. Included are system

components shared jointly with the military.

NATIONAL BEACON CODE ALLOCATION

PLAN AIRSPACE− Airspace over United States

territory located within the North American continent

between Canada and Mexico, including adjacent

territorial waters outward to about boundaries of

oceanic control areas (CTA)/Flight Information

Regions (FIR).

(See FLIGHT INFORMATION REGION.)

NATIONAL FLIGHT DATA CENTER− A facility in

Washington D.C., established by FAA to operate a

central aeronautical information service for the

collection, validation, and dissemination of

aeronautical data in support of the activities of

government, industry, and the aviation community.

The information is published in the National Flight

Data Digest.

(See NATIONAL FLIGHT DATA DIGEST.)

NATIONAL FLIGHT DATA DIGEST− A daily

(except weekends and Federal holidays) publication

of flight information appropriate to aeronautical

charts, aeronautical publications, Notices to Airmen,

or other media serving the purpose of providing

operational flight data essential to safe and efficient

aircraft operations.

NATIONAL SEARCH AND RESCUE PLAN− An

interagency agreement which provides for the

effective utilization of all available facilities in all

types of search and rescue missions.

NAVAID−

(See NAVIGATIONAL AID.)

NAVAID CLASSES− VOR, VORTAC, and TACAN

aids are classed according to their operational use.

The three classes of NAVAIDs are:

a. T− Terminal.

b. L− Low altitude.

c. H− High altitude.

Note: The normal service range for T, L, and H class

aids is found in the AIM. Certain operational

requirements make it necessary to use some of

these aids at greater service ranges than

specified. Extended range is made possible

through flight inspection determinations. Some

aids also have lesser service range due to location,

terrain, frequency protection, etc. Restrictions to

service range are listed in Chart Supplement U.S.

NAVIGABLE AIRSPACE− Airspace at and above

the minimum flight altitudes prescribed in the CFRs

including airspace needed for safe takeoff and

landing.

(Refer to 14 CFR Part 91.)

NAVIGATION REFERENCE SYSTEM (NRS)−

The NRS is a system of waypoints developed for use

within the United States for flight planning and

navigation without reference to ground based

navigational aids. The NRS waypoints are located in

a grid pattern along defined latitude and longitude

lines. The initial use of the NRS will be in the high

altitude environment in conjunction with the High

Altitude Redesign initiative. The NRS waypoints are

intended for use by aircraft capable of point−to−point

navigation.

NAVIGATION SPECIFICATION [ICAO]− A set of

aircraft and flight crew requirements needed to

support performance−based navigation operations

within a defined airspace. There are two kinds of

navigation specifications:

a. RNP specification. A navigation specification

based on area navigation that includes the

requirement for performance monitoring and

alerting, designated by the prefix RNP; e.g., RNP 4,

RNP APCH.

b. RNAV specification. A navigation specifica-

tion based on area navigation that does not include the

requirement for performance monitoring and alert-

Pilot/Controller Glossary 10/12/17

PCG N−2

ing, designated by the prefix RNAV; e.g., RNAV 5,

RNAV 1.

Note: The Performance−based Navigation Manual

(Doc 9613), Volume II contains detailed guidance

on navigation specifications.

NAVIGATIONAL AID− Any visual or electronic

device airborne or on the surface which provides

point-to-point guidance information or position data

to aircraft in flight.

(See AIR NAVIGATION FACILITY.)

NBCAP AIRSPACE−

(See NATIONAL BEACON CODE ALLOCATION

PLAN AIRSPACE.)

NDB−

(See NONDIRECTIONAL BEACON.)

NEGATIVE− “No,” or “permission not granted,” or

“that is not correct.”

NEGATIVE CONTACT− Used by pilots to inform

ATC that:

a. Previously issued traffic is not in sight. It may

be followed by the pilot’s request for the controller to

provide assistance in avoiding the traffic.

b. They were unable to contact ATC on a

particular frequency.

NFDC−

(See NATIONAL FLIGHT DATA CENTER.)

NFDD−

(See NATIONAL FLIGHT DATA DIGEST.)

NIGHT− The time between the end of evening civil

twilight and the beginning of morning civil twilight,

as published in the Air Almanac, converted to local

time.

(See ICAO term NIGHT.)

NIGHT [ICAO]− The hours between the end of

evening civil twilight and the beginning of morning

civil twilight or such other period between sunset and

sunrise as may be specified by the appropriate

authority.

Note: Civil twilight ends in the evening when the

center of the sun’s disk is 6 degrees below the

horizon and begins in the morning when the center

of the sun’s disk is 6 degrees below the horizon.

NO GYRO APPROACH− A radar approach/vector

provided in case of a malfunctioning gyro-compass

or directional gyro. Instead of providing the pilot

with headings to be flown, the controller observes the

radar track and issues control instructions “turn

right/left” or “stop turn” as appropriate.

(Refer to AIM.)

NO GYRO VECTOR−

(See NO GYRO APPROACH.)

NO TRANSGRESSION ZONE (NTZ)− The NTZ is

a 2,000 foot wide zone, located equidistant between

parallel runway or SOIA final approach courses in

which flight is normally not allowed.

NONAPPROACH CONTROL TOWER− Author-

izes aircraft to land or takeoff at the airport controlled

by the tower or to transit the Class D airspace. The

primary function of a nonapproach control tower is

the sequencing of aircraft in the traffic pattern and on

the landing area. Nonapproach control towers also

separate aircraft operating under instrument flight

rules clearances from approach controls and centers.

They provide ground control services to aircraft,

vehicles, personnel, and equipment on the airport

movement area.

NONCOMMON ROUTE/PORTION− That segment

of a North American Route between the inland

navigation facility and a designated North American

terminal.

NONCOMPOSITE SEPARATION− Separation in

accordance with minima other than the composite

separation minimum specified for the area con-

cerned.

NONDIRECTIONAL BEACON− An L/MF or UHF

radio beacon transmitting nondirectional signals

whereby the pilot of an aircraft equipped with

direction finding equipment can determine his/her

bearing to or from the radio beacon and “home” on or

track to or from the station. When the radio beacon is

installed in conjunction with the Instrument Landing

System marker, it is normally called a Compass

Locator.

(See AUTOMATIC DIRECTION FINDER.)

(See COMPASS LOCATOR.)

NONMOVEMENT AREAS− Taxiways and apron

(ramp) areas not under the control of air traffic.

NONPRECISION APPROACH−

(See NONPRECISION APPROACH

PROCEDURE.)

NONPRECISION APPROACH PROCEDURE− A

standard instrument approach procedure in which no

Pilot/Controller Glossary

10/12/17

PCG N−3

electronic glideslope is provided; e.g., VOR,

TACAN, NDB, LOC, ASR, LDA, or SDF

approaches.

NONRADAR− Precedes other terms and generally

means without the use of radar, such as:

a. Nonradar Approach. Used to describe

instrument approaches for which course guidance on

final approach is not provided by ground-based

precision or surveillance radar. Radar vectors to the

final approach course may or may not be provided by

ATC. Examples of nonradar approaches are VOR,

NDB, TACAN, ILS, RNAV, and GLS approaches.

(See FINAL APPROACH COURSE.)

(See FINAL APPROACH-IFR.)

(See INSTRUMENT APPROACH

PROCEDURE.)

(See RADAR APPROACH.)

b. Nonradar Approach Control. An ATC facility

providing approach control service without the use of

radar.

(See APPROACH CONTROL FACILITY.)

(See APPROACH CONTROL SERVICE.)

c. Nonradar Arrival. An aircraft arriving at an

airport without radar service or at an airport served by

a radar facility and radar contact has not been

established or has been terminated due to a lack of

radar service to the airport.

(See RADAR ARRIVAL.)

(See RADAR SERVICE.)

d. Nonradar Route. A flight path or route over

which the pilot is performing his/her own navigation.

The pilot may be receiving radar separation, radar

monitoring, or other ATC services while on a

nonradar route.

(See RADAR ROUTE.)

e. Nonradar Separation. The spacing of aircraft in

accordance with established minima without the use

of radar; e.g., vertical, lateral, or longitudinal

separation.

(See RADAR SEPARATION.)

NON−RESTRICTIVE ROUTING (NRR)− Portions

of a proposed route of flight where a user can flight

plan the most advantageous flight path with no

requirement to make reference to ground−based

NAVAIDs.

NOPAC−

(See NORTH PACIFIC.)

NORDO (No Radio)− Aircraft that cannot or do not

communicate by radio when radio communication is

required are referred to as “NORDO.”

(See LOST COMMUNICATIONS.)

NORMAL OPERATING ZONE (NOZ)− The NOZ

is the operating zone within which aircraft flight

remains during normal independent simultaneous

parallel ILS approaches.

NORTH AMERICAN ROUTE− A numerically

coded route preplanned over existing airway and

route systems to and from specific coastal fixes

serving the North Atlantic. North American Routes

consist of the following:

a. Common Route/Portion. That segment of a

North American Route between the inland navigation

facility and the coastal fix.

b. Noncommon Route/Portion. That segment of a

North American Route between the inland navigation

facility and a designated North American terminal.

c. Inland Navigation Facility. A navigation aid on

a North American Route at which the common route

and/or the noncommon route begins or ends.

d. Coastal Fix. A navigation aid or intersection

where an aircraft transitions between the domestic

route structure and the oceanic route structure.

NORTH AMERICAN ROUTE PROGRAM (NRP)−

The NRP is a set of rules and procedures which are

designed to increase the flexibility of user flight

planning within published guidelines.

NORTH ATLANTIC HIGH LEVEL AIRSPACE

(NAT HLA)− That volume of airspace (as defined in

ICAO Document 7030) between FL 285 and FL 420

within the Oceanic Control Areas of Bodo Oceanic,

Gander Oceanic, New York Oceanic East, Reykjavik,

Santa Maria, and Shanwick, excluding the Shannon

and Brest Ocean Transition Areas. ICAO Doc 007

North Atlantic Operations and Airspace Manual

provides detailed information on related aircraft and

operational requirements.

NORTH MARK− A beacon data block sent by the

host computer to be displayed by the ARTS on a 360

degree bearing at a locally selected radar azimuth and

distance. The North Mark is used to ensure correct

range/azimuth orientation during periods of

CENRAP.

NORTH PACIFIC− An organized route system

between the Alaskan west coast and Japan.

Pilot/Controller Glossary 10/12/17

PCG N−4

NOT STANDARD− Varying from what is expected

or published. For use in NOTAMs only.

NOT STD-

(See NOT STANDARD)

NOTAM−

(See NOTICE TO AIRMEN.)

NOTAM [ICAO]− A notice containing information

concerning the establishment, condition or change in

any aeronautical facility, service, procedure or

hazard, the timely knowledge of which is essential to

personnel concerned with flight operations.

a. I Distribution− Distribution by means of

telecommunication.

b. II Distribution− Distribution by means other

than telecommunications.

NOTICE TO AIRMEN− A notice containing

information (not known sufficiently in advance to

publicize by other means) concerning the

establishment, condition, or change in any

component (facility, service, or procedure of, or

hazard in the National Airspace System) the timely

knowledge of which is essential to personnel

concerned with flight operations.

NOTAM(D)− A NOTAM given (in addition to local

dissemination) distant dissemination beyond the area

of responsibility of the Flight Service Station. These

NOTAMs will be stored and available until canceled.

c. FDC NOTAM− A NOTAM regulatory in

nature, transmitted by USNOF and given system

wide dissemination.

(See ICAO term NOTAM.)

NOTICES TO AIRMEN PUBLICATION− A

publication issued every 28 days, designed primarily

for the pilot, which contains current NOTAM

information considered essential to the safety of

flight as well as supplemental data to other

aeronautical publications. The contraction NTAP is

used in NOTAM text.

(See NOTICE TO AIRMEN.)

NRR−

(See NON−RESTRICTIVE ROUTING.)

NRS−

(See NAVIGATION REFERENCE SYSTEM.)

NTAP−

(See NOTICES TO AIRMEN PUBLICATION.)

NUMEROUS TARGETS VICINITY (LOCA-

TION)− A traffic advisory issued by ATC to advise

pilots that targets on the radar scope are too numerous

to issue individually.

(See TRAFFIC ADVISORIES.)

Pilot/Controller Glossary

10/12/17

PCG O−1

OBSTACLE− An existing object, object of natural

growth, or terrain at a fixed geographical location or

which may be expected at a fixed location within a

prescribed area with reference to which vertical

clearance is or must be provided during flight

operation.

OBSTACLE DEPARTURE PROCEDURE (ODP)−

A preplanned instrument flight rule (IFR) departure

procedure printed for pilot use in textual or graphic

form to provide obstruction clearance via the least

onerous route from the terminal area to the

appropriate en route structure. ODPs are recom-

mended for obstruction clearance and may be flown

without ATC clearance unless an alternate departure

procedure (SID or radar vector) has been specifically

assigned by ATC.

(See IFR TAKEOFF MINIMUMS AND

DEPARTURE PROCEDURES.)

(See STANDARD INSTRUMENT

DEPARTURES.)

(Refer to AIM.)

OBSTACLE FREE ZONE− The OFZ is a three

dimensional volume of airspace which protects for

the transition of aircraft to and from the runway. The

OFZ clearing standard precludes taxiing and parked

airplanes and object penetrations, except for

frangible NAVAID locations that are fixed by

function. Additionally, vehicles, equipment, and

personnel may be authorized by air traffic control to

enter the area using the provisions of FAA Order

JO 7110.65, Para 3−1−5, Vehicles/Equipment/Per-

sonnal Near/On Runways. The runway OFZ and

when applicable, the inner-approach OFZ, and the

inner-transitional OFZ, comprise the OFZ.

a. Runway OFZ. The runway OFZ is a defined

volume of airspace centered above the runway. The

runway OFZ is the airspace above a surface whose

elevation at any point is the same as the elevation of

the nearest point on the runway centerline. The

runway OFZ extends 200 feet beyond each end of the

runway. The width is as follows:

1. For runways serving large airplanes, the

greater of:

(a) 400 feet, or

(b) 180 feet, plus the wingspan of the most

demanding airplane, plus 20 feet per 1,000 feet of

airport elevation.

2. For runways serving only small airplanes:

(a) 300 feet for precision instrument run-

ways.

(b) 250 feet for other runways serving small

airplanes with approach speeds of 50 knots, or more.

airplanes with approach speeds of less than 50 knots.

b. Inner-approach OFZ. The inner-approach OFZ

is a defined volume of airspace centered on the

approach area. The inner-approach OFZ applies only

to runways with an approach lighting system. The

inner-approach OFZ begins 200 feet from the runway

threshold at the same elevation as the runway

threshold and extends 200 feet beyond the last light

unit in the approach lighting system. The width of the

inner-approach OFZ is the same as the runway OFZ

and rises at a slope of 50 (horizontal) to 1 (vertical)

from the beginning.

c. Inner-transitional OFZ. The inner transitional

surface OFZ is a defined volume of airspace along the

sides of the runway and inner-approach OFZ and

applies only to precision instrument runways. The

inner-transitional surface OFZ slopes 3 (horizontal)

to 1 (vertical) out from the edges of the runway OFZ

and inner-approach OFZ to a height of 150 feet above

the established airport elevation.

(Refer to AC 150/5300-13, Chapter 3.)

(Refer to FAA Order JO 7110.65, Para 3−1−5,

Vehicles/Equipment/Personnel Near/On

Runways.)

OBSTRUCTION− Any object/obstacle exceeding

the obstruction standards specified by 14 CFR

Part 77, Subpart C.

OBSTRUCTION LIGHT− A light or one of a group

of lights, usually red or white, frequently mounted on

a surface structure or natural terrain to warn pilots of

the presence of an obstruction.

OCEANIC AIRSPACE− Airspace over the oceans of

the world, considered international airspace, where

oceanic separation and procedures per the Interna-

tional Civil Aviation Organization are applied.

Responsibility for the provisions of air traffic control

Pilot/Controller Glossary 10/12/17

PCG O−2

service in this airspace is delegated to various

countries, based generally upon geographic proxim-

ity and the availability of the required resources.

OCEANIC ERROR REPORT− A report filed when

ATC observes an Oceanic Error as defined by

FAAO 7110.82, Reporting Oceanic Errors.

OCEANIC PUBLISHED ROUTE− A route estab-

lished in international airspace and charted or

described in flight information publications, such as

Route Charts, DOD En route Charts, Chart

Supplements, NOTAMs, and Track Messages.

OCEANIC TRANSITION ROUTE− An ATS route

established for the purpose of transitioning aircraft

to/from an organized track system.

ODP−

(See OBSTACLE DEPARTURE PROCEDURE.)

OFF COURSE− A term used to describe a situation

where an aircraft has reported a position fix or is

observed on radar at a point not on the ATC-approved

route of flight.

OFF-ROUTE VECTOR− A vector by ATC which

takes an aircraft off a previously assigned route.

Altitudes assigned by ATC during such vectors

provide required obstacle clearance.

OFFSET PARALLEL RUNWAYS− Staggered

runways having centerlines which are parallel.

OFFSHORE/CONTROL AIRSPACE AREA− That

portion of airspace between the U.S. 12 NM limit and

the oceanic CTA/FIR boundary within which air

traffic control is exercised. These areas are

established to provide air traffic control services.

Offshore/Control Airspace Areas may be classified

as either Class A airspace or Class E airspace.

OFT−

(See OUTER FIX TIME.)

OM−

(See OUTER MARKER.)

ON COURSE−

a. Used to indicate that an aircraft is established on

the route centerline.

b. Used by ATC to advise a pilot making a radar

approach that his/her aircraft is lined up on the final

approach course.

(See ON-COURSE INDICATION.)

ON-COURSE INDICATION− An indication on an

instrument, which provides the pilot a visual means

of determining that the aircraft is located on the

centerline of a given navigational track, or an

indication on a radar scope that an aircraft is on a

given track.

ONE-MINUTE WEATHER− The most recent one

minute updated weather broadcast received by a pilot

from an uncontrolled airport ASOS/AWSS/AWOS.

ONER−

(See OCEANIC NAVIGATIONAL ERROR

REPORT.)

OPERATIONAL−

(See DUE REGARD.)

OPERATIONS SPECIFICATIONS [ICAO]− The

authorizations, conditions and limitations associated

with the air operator certificate and subject to the

conditions in the operations manual.

OPPOSITE DIRECTION AIRCRAFT− Aircraft are

operating in opposite directions when:

a. They are following the same track in reciprocal

directions; or

b. Their tracks are parallel and the aircraft are

flying in reciprocal directions; or

c. Their tracks intersect at an angle of more than

135_.

OPTION APPROACH− An approach requested and

conducted by a pilot which will result in either a

touch-and-go, missed approach, low approach,

stop-and-go, or full stop landing. Pilots should advise

ATC if they decide to remain on the runway, of any

delay in their stop and go, delay clearing the runway,

or are unable to comply with the instruction(s).

(See CLEARED FOR THE OPTION.)

(Refer to AIM.)

ORGANIZED TRACK SYSTEM− A series of ATS

routes which are fixed and charted; i.e., CEP,

NOPAC, or flexible and described by NOTAM; i.e.,

NAT TRACK MESSAGE.

Pilot/Controller Glossary

10/12/17

PCG O−3

OROCA− An off-route altitude which provides

obstruction clearance with a 1,000 foot buffer in

non−mountainous terrain areas and a 2,000 foot

buffer in designated mountainous areas within the

United States. This altitude may not provide signal

coverage from ground-based navigational aids, air

traffic control radar, or communications coverage.

OTR−

(See OCEANIC TRANSITION ROUTE.)

OTS−

(See ORGANIZED TRACK SYSTEM.)

OUT− The conversation is ended and no response is

expected.

OUT OF SERVICE− When a piece of equipment, a

system, a facility or a service is not operational,

certified (if required) and immediately “available”

for Air Traffic or public use.

OUTER AREA (associated with Class C airspace)−

Non−regulatory airspace surrounding designated

Class C airspace airports wherein ATC provides radar

vectoring and sequencing on a full-time basis for all

IFR and participating VFR aircraft. The service

provided in the outer area is called Class C service

which includes: IFR/IFR−IFR separation; IFR/

VFR−traffic advisories and conflict resolution; and

VFR/VFR−traffic advisories and, as appropriate,

safety alerts. The normal radius will be 20 nautical

miles with some variations based on site-specific

requirements. The outer area extends outward from

the primary Class C airspace airport and extends from

the lower limits of radar/radio coverage up to the

ceiling of the approach control’s delegated airspace

excluding the Class C charted area and other airspace

as appropriate.

(See CONFLICT RESOLUTION.)

(See CONTROLLED AIRSPACE.)

OUTER COMPASS LOCATOR−

(See COMPASS LOCATOR.)

OUTER FIX− A general term used within ATC to

describe fixes in the terminal area, other than the final

approach fix. Aircraft are normally cleared to these

fixes by an Air Route Traffic Control Center or an

Approach Control Facility. Aircraft are normally

cleared from these fixes to the final approach fix or

final approach course.

OUTER FIX− An adapted fix along the converted

route of flight, prior to the meter fix, for which

crossing times are calculated and displayed in the

metering position list.

OUTER FIX ARC− A semicircle, usually about a

50−70 mile radius from a meter fix, usually in high

altitude, which is used by CTAS/HOST to calculate

outer fix times and determine appropriate sector

meter list assignments for aircraft on an established

arrival route that will traverse the arc.

OUTER FIX TIME− A calculated time to depart the

outer fix in order to cross the vertex at the ACLT. The

time reflects descent speed adjustments and any

applicable delay time that must be absorbed prior to

crossing the meter fix.

OUTER MARKER− A marker beacon at or near the

glideslope intercept altitude of an ILS approach. It is

keyed to transmit two dashes per second on a 400 Hz

tone, which is received aurally and visually by

compatible airborne equipment. The OM is normally

located four to seven miles from the runway threshold

on the extended centerline of the runway.

(See INSTRUMENT LANDING SYSTEM.)

(See MARKER BEACON.)

(Refer to AIM.)

OVER− My transmission is ended; I expect a

response.

OVERHEAD MANEUVER− A series of predeter-

mined maneuvers prescribed for aircraft (often in

formation) for entry into the visual flight rules (VFR)

traffic pattern and to proceed to a landing. An

overhead maneuver is not an instrument flight rules

(IFR) approach procedure. An aircraft executing an

overhead maneuver is considered VFR and the IFR

flight plan is cancelled when the aircraft reaches the

“initial point” on the initial approach portion of the

maneuver. The pattern usually specifies the

following:

a. The radio contact required of the pilot.

b. The speed to be maintained.

c. An initial approach 3 to 5 miles in length.

d. An elliptical pattern consisting of two 180

degree turns.

e. A break point at which the first 180 degree turn

is started.

f. The direction of turns.

g. Altitude (at least 500 feet above the convention-

al pattern).

Pilot/Controller Glossary 10/12/17

PCG O−4

h. A “Roll-out” on final approach not less than 1/4

mile from the landing threshold and not less than 300

feet above the ground.

OVERLYING CENTER− The ARTCC facility that

is responsible for arrival/departure operations at a

specific terminal.

Pilot/Controller Glossary

10/12/17

PCG P−1

P TIME−

(See PROPOSED DEPARTURE TIME.)

P-ACP−

(See PREARRANGED COORDINATION

PROCEDURES.)

PAN-PAN− The international radio-telephony urgen-

cy signal. When repeated three times, indicates

uncertainty or alert followed by the nature of the

urgency.

(See MAYDAY.)

(Refer to AIM.)

PAR−

(See PRECISION APPROACH RADAR.)

PAR [ICAO]−

(See ICAO Term PRECISION APPROACH

RADAR.)

PARALLEL ILS APPROACHES− Approaches to

parallel runways by IFR aircraft which, when

established inbound toward the airport on the

adjacent final approach courses, are radar-separated

by at least 2 miles.

(See FINAL APPROACH COURSE.)

(See SIMULTANEOUS ILS APPROACHES.)

PARALLEL OFFSET ROUTE− A parallel track to

the left or right of the designated or established

airway/route. Normally associated with Area Navi-

gation (RNAV) operations.

(See AREA NAVIGATION.)

PARALLEL RUNWAYS− Two or more runways at

the same airport whose centerlines are parallel. In

addition to runway number, parallel runways are

designated as L (left) and R (right) or, if three parallel

runways exist, L (left), C (center), and R (right).

PBCT−

(See PROPOSED BOUNDARY CROSSING

TIME.)

PBN

(See ICAO Term PERFORMANCE−BASED

NAVIGATION.)

PDC−

(See PRE−DEPARTURE CLEARANCE.)

PERFORMANCE−BASED NAVIGATION (PBN)

[ICAO]− Area navigation based on performance

requirements for aircraft operating along an ATS

route, on an instrument approach procedure or in a

designated airspace.

Note: Performance requirements are expressed in

navigation specifications (RNAV specification,

RNP specification) in terms of accuracy, integrity,

continuity, availability, and functionality needed for

the proposed operation in the context of a

particular airspace concept.

PERMANENT ECHO− Radar signals reflected from

fixed objects on the earth’s surface; e.g., buildings,

towers, terrain. Permanent echoes are distinguished

from “ground clutter” by being definable locations

rather than large areas. Under certain conditions they

may be used to check radar alignment.

PHOTO RECONNAISSANCE− Military activity

that requires locating individual photo targets and

navigating to the targets at a preplanned angle and

altitude. The activity normally requires a lateral route

width of 16 NM and altitude range of 1,500 feet to

10,000 feet AGL.

PILOT BRIEFING− A service provided by the FSS

to assist pilots in flight planning. Briefing items may

include weather information, NOTAMS, military

activities, flow control information, and other items

as requested.

(Refer to AIM.)

PILOT IN COMMAND− The pilot responsible for

the operation and safety of an aircraft during flight

time.

(Refer to 14 CFR Part 91.)

PILOT WEATHER REPORT− A report of meteoro-

logical phenomena encountered by aircraft in flight.

(Refer to AIM.)

PILOT’S DISCRETION− When used in conjunc-

tion with altitude assignments, means that ATC has

offered the pilot the option of starting climb or

descent whenever he/she wishes and conducting the

climb or descent at any rate he/she wishes. He/she

may temporarily level off at any intermediate

altitude. However, once he/she has vacated an

altitude, he/she may not return to that altitude.

Pilot/Controller Glossary 10/12/17

PCG P−2

PIREP−

(See PILOT WEATHER REPORT.)

PITCH POINT− A fix/waypoint that serves as a

transition point from a departure procedure or the low

altitude ground−based navigation structure into the

high altitude waypoint system.

PLANS DISPLAY− A display available in EDST

that provides detailed flight plan and predicted

conflict information in textual format for requested

Current Plans and all Trial Plans.

(See EN ROUTE DECISION SUPPORT TOOL)

POFZ−

(See PRECISION OBSTACLE FREE ZONE.)

POINT OUT−

(See RADAR POINT OUT.)

POINT−TO−POINT (PTP)− A level of NRR service

for aircraft that is based on traditional waypoints in

their FMSs or RNAV equipage.

POLAR TRACK STRUCTURE− A system of

organized routes between Iceland and Alaska which

overlie Canadian MNPS Airspace.

POSITION REPORT− A report over a known

location as transmitted by an aircraft to ATC.

(Refer to AIM.)

POSITION SYMBOL− A computer-generated

indication shown on a radar display to indicate the

mode of tracking.

POSITIVE CONTROL− The separation of all air

traffic within designated airspace by air traffic

control.

PRACTICE INSTRUMENT APPROACH− An

instrument approach procedure conducted by a VFR

or an IFR aircraft for the purpose of pilot training or

proficiency demonstrations.

PRE−DEPARTURE CLEARANCE− An application

with the Terminal Data Link System (TDLS) that

provides clearance information to subscribers,

through a service provider, in text to the cockpit or

gate printer.

PREARRANGED COORDINATION− A standard-

ized procedure which permits an air traffic controller

to enter the airspace assigned to another air traffic

controller without verbal coordination. The proce-

dures are defined in a facility directive which ensures

approved separation between aircraft.

PREARRANGED COORDINATION PROCE-

DURES− A facility’s standardized procedure that

describes the process by which one controller shall

allow an aircraft to penetrate or transit another

controller’s airspace in a manner that assures

approved separation without individual coordination

for each aircraft.

PRECIPITATION− Any or all forms of water

particles (rain, sleet, hail, or snow) that fall from the

atmosphere and reach the surface.

PRECIPITATION RADAR WEATHER DESCRIP-

TIONS− Existing radar systems cannot detect

turbulence. However, there is a direct correlation

between the degree of turbulence and other weather

features associated with thunderstorms and the

weather radar precipitation intensity. Controllers will

issue (where capable) precipitation intensity as

observed by radar when using weather and radar

processor (WARP) or NAS ground based digital

radars with weather capabilities. When precipitation

intensity information is not available, the intensity

will be described as UNKNOWN. When intensity

levels can be determined, they shall be described as:

a. LIGHT (< 26 dBZ)

b. MODERATE (26 to 40 dBZ)

c. HEAVY (> 40 to 50 dBZ)

d. EXTREME (> 50 dBZ)

(Refer to AC 00−45, Aviation Weather Services.)

PRECISION APPROACH−

(See PRECISION APPROACH PROCEDURE.)

PRECISION APPROACH PROCEDURE− A

standard instrument approach procedure in which an

electronic glideslope/or other type of glidepath is

provided ; e.g., ILS, PAR, and GLS.

(See INSTRUMENT LANDING SYSTEM.)

(See PRECISION APPROACH RADAR.)

Pilot/Controller Glossary

10/12/17

PCG P−3

PRECISION APPROACH RADAR− Radar equip-

ment in some ATC facilities operated by the FAA

and/or the military services at joint-use civil/military

locations and separate military installations to detect

and display azimuth, elevation, and range of aircraft

on the final approach course to a runway. This

equipment may be used to monitor certain non−radar

approaches, but is primarily used to conduct a

precision instrument approach (PAR) wherein the

controller issues guidance instructions to the pilot

based on the aircraft’s position in relation to the final

approach course (azimuth), the glidepath (elevation),

and the distance (range) from the touchdown point on

the runway as displayed on the radar scope.

Note: The abbreviation “PAR” is also used to

denote preferential arrival routes in ARTCC

computers.

(See GLIDEPATH.)

(See PAR.)

(See PREFERENTIAL ROUTES.)

(See ICAO term PRECISION APPROACH

RADAR.)

(Refer to AIM.)

PRECISION APPROACH RADAR [ICAO]− Pri-

mary radar equipment used to determine the position

of an aircraft during final approach, in terms of lateral

and vertical deviations relative to a nominal approach

path, and in range relative to touchdown.

Note: Precision approach radars are designed to

enable pilots of aircraft to be given guidance by

radio communication during the final stages of the

approach to land.

PRECISION OBSTACLE FREE ZONE (POFZ)−

An 800 foot wide by 200 foot long area centered on

the runway centerline adjacent to the threshold

designed to protect aircraft flying precision

approaches from ground vehicles and other aircraft

when ceiling is less than 250 feet or visibility is less

than 3/4 statute mile (or runway visual range below

4,000 feet.)

PRECISION RUNWAY MONITOR (PRM)

SYSTEM− Provides air traffic controllers

monitoring the NTZ during simultaneous close

parallel PRM approaches with precision, high update

rate secondary surveillance data. The high update rate

surveillance sensor component of the PRM system is

only required for specific runway or approach course

separation. The high resolution color monitoring

display, Final Monitor Aid (FMA) of the PRM

system, or other FMA with the same capability,

presents (NTZ) surveillance track data to controllers

along with detailed maps depicting approaches and

no transgression zone and is required for all

simultaneous close parallel PRM NTZ monitoring

operations.

(Refer to AIM)

PREDICTIVE WIND SHEAR ALERT SYSTEM

(PWS)− A self−contained system used onboard some

aircraft to alert the flight crew to the presence of a

potential wind shear. PWS systems typically monitor

3 miles ahead and 25 degrees left and right of the

aircraft’s heading at or below 1200’ AGL. Departing

flights may receive a wind shear alert after they start

the takeoff roll and may elect to abort the takeoff.

Aircraft on approach receiving an alert may elect to

go around or perform a wind shear escape maneuver.

PREFERENTIAL ROUTES− Preferential routes

(PDRs, PARs, and PDARs) are adapted in ARTCC

computers to accomplish inter/intrafacility controller

coordination and to assure that flight data is posted at

the proper control positions. Locations having a need

for these specific inbound and outbound routes

normally publish such routes in local facility

bulletins, and their use by pilots minimizes flight

plan route amendments. When the workload or traffic

situation permits, controllers normally provide radar

vectors or assign requested routes to minimize

circuitous routing. Preferential routes are usually

confined to one ARTCC’s area and are referred to by

the following names or acronyms:

a. Preferential Departure Route (PDR). A specific

departure route from an airport or terminal area to an

en route point where there is no further need for flow

control. It may be included in an Instrument

Departure Procedure (DP) or a Preferred IFR Route.

b. Preferential Arrival Route (PAR). A specific

arrival route from an appropriate en route point to an

airport or terminal area. It may be included in a

Standard Terminal Arrival (STAR) or a Preferred IFR

Route. The abbreviation “PAR” is used primarily

within the ARTCC and should not be confused with

the abbreviation for Precision Approach Radar.

c. Preferential Departure and Arrival Route

(PDAR). A route between two terminals which are

within or immediately adjacent to one ARTCC’s area.

PDARs are not synonymous with Preferred IFR

Routes but may be listed as such as they do

accomplish essentially the same purpose.

(See PREFERRED IFR ROUTES.)

Pilot/Controller Glossary 10/12/17

PCG P−4

PREFERRED IFR ROUTES− Routes established

between busier airports to increase system efficiency

and capacity. They normally extend through one or

more ARTCC areas and are designed to achieve

balanced traffic flows among high density terminals.

IFR clearances are issued on the basis of these routes

except when severe weather avoidance procedures or

other factors dictate otherwise. Preferred IFR Routes

are listed in the Chart Supplement U.S. If a flight is

planned to or from an area having such routes but the

departure or arrival point is not listed in the Chart

Supplement U.S., pilots may use that part of a

Preferred IFR Route which is appropriate for the

departure or arrival point that is listed. Preferred IFR

Routes are correlated with DPs and STARs and may

be defined by airways, jet routes, direct routes

between NAVAIDs, Waypoints, NAVAID radials/

DME, or any combinations thereof.

(See CENTER’S AREA.)

(See INSTRUMENT DEPARTURE

PROCEDURE.)

(See PREFERENTIAL ROUTES.)

(See STANDARD TERMINAL ARRIVAL.)

(Refer to CHART SUPPLEMENT U.S.)

(Refer to NOTICES TO AIRMEN PUBLICATION.)

PRE-FLIGHT PILOT BRIEFING−

(See PILOT BRIEFING.)

PREVAILING VISIBILITY−

(See VISIBILITY.)

PRIMARY RADAR TARGET− An analog or digital

target, exclusive of a secondary radar target,

presented on a radar display.

PRM−

(See ILS PRM APPROACH and PRECISION

RUNWAY MONITOR SYSTEM.)

PROCEDURAL CONTROL [ICAO]– Term used to

indicate that information derived from an ATS

surveillance system is not required for the provision

of air traffic control service.

PROCEDURAL SEPARATION [ICAO]– The sepa-

ration used when providing procedural control.

PROCEDURE TURN− The maneuver prescribed

when it is necessary to reverse direction to establish

an aircraft on the intermediate approach segment or

final approach course. The outbound course,

direction of turn, distance within which the turn must

be completed, and minimum altitude are specified in

the procedure. However, unless otherwise restricted,

the point at which the turn may be commenced and

the type and rate of turn are left to the discretion of the

pilot.

(See ICAO term PROCEDURE TURN.)

PROCEDURE TURN [ICAO]− A maneuver in

which a turn is made away from a designated track

followed by a turn in the opposite direction to permit

the aircraft to intercept and proceed along the

reciprocal of the designated track.

Note 1: Procedure turns are designated “left” or

“right” according to the direction of the initial turn.

Note 2: Procedure turns may be designated as

being made either in level flight or while

descending, according to the circumstances of

each individual approach procedure.

PROCEDURE TURN INBOUND− That point of a

procedure turn maneuver where course reversal has

been completed and an aircraft is established inbound

on the intermediate approach segment or final

approach course. A report of “procedure turn

inbound” is normally used by ATC as a position

report for separation purposes.

(See FINAL APPROACH COURSE.)

(See PROCEDURE TURN.)

(See SEGMENTS OF AN INSTRUMENT

APPROACH PROCEDURE.)

PROFILE DESCENT− An uninterrupted descent

(except where level flight is required for speed

adjustment; e.g., 250 knots at 10,000 feet MSL) from

cruising altitude/level to interception of a glideslope

or to a minimum altitude specified for the initial or

intermediate approach segment of a nonprecision

instrument approach. The profile descent normally

terminates at the approach gate or where the

glideslope or other appropriate minimum altitude is

intercepted.

PROGRESS REPORT−

(See POSITION REPORT.)

PROGRESSIVE TAXI− Precise taxi instructions

given to a pilot unfamiliar with the airport or issued

in stages as the aircraft proceeds along the taxi route.

PROHIBITED AREA−

(See SPECIAL USE AIRSPACE.)

(See ICAO term PROHIBITED AREA.)

PROHIBITED AREA [ICAO]− An airspace of

defined dimensions, above the land areas or territorial

waters of a State, within which the flight of aircraft

is prohibited.

Pilot/Controller Glossary

10/12/17

PCG P−5

PROMINENT OBSTACLE– An obstacle that meets

one or more of the following conditions:

a. An obstacle which stands out beyond the

adjacent surface of surrounding terrain and immedi-

ately projects a noticeable hazard to aircraft in flight.

b. An obstacle, not characterized as low and close

in, whose height is no less than 300 feet above the

departure end of takeoff runway (DER) elevation, is

within 10NM from the DER, and that penetrates that

airport/heliport’s diverse departure obstacle clear-

ance surface (OCS).

c. An obstacle beyond 10NM from an airport/heli-

port that requires an obstacle departure procedure

(ODP) to ensure obstacle avoidance.

(See OBSTACLE.)

(See OBSTRUCTION.)

PROPOSED BOUNDARY CROSSING TIME−

Each center has a PBCT parameter for each internal

airport. Proposed internal flight plans are transmitted

to the adjacent center if the flight time along the

proposed route from the departure airport to the

center boundary is less than or equal to the value of

PBCT or if airport adaptation specifies transmission

regardless of PBCT.

PROPOSED DEPARTURE TIME− The time that the

aircraft expects to become airborne.

PROTECTED AIRSPACE− The airspace on either

side of an oceanic route/track that is equal to one-half

the lateral separation minimum except where

reduction of protected airspace has been authorized.

PROTECTED SEGMENT- The protected segment is

a segment on the amended TFM route that is to be

inhibited from automatic adapted route alteration by

ERAM.

PT−

(See PROCEDURE TURN.)

PTP−

(See POINT−TO−POINT.)

PTS−

(See POLAR TRACK STRUCTURE.)

PUBLISHED INSTRUMENT APPROACH

PROCEDURE VISUAL SEGMENT− A segment on

an IAP chart annotated as “Fly Visual to Airport” or

“Fly Visual.” A dashed arrow will indicate the visual

flight path on the profile and plan view with an

associated note on the approximate heading and

distance. The visual segment should be flown as a

dead reckoning course while maintaining visual

conditions.

PUBLISHED ROUTE− A route for which an IFR

altitude has been established and published; e.g.,

Federal Airways, Jet Routes, Area Navigation

Routes, Specified Direct Routes.

PWS−

(See PREDICTIVE WIND SHEAR ALERT

SYSTEM.)

Pilot/Controller Glossary

10/12/17

PCG Q−1

Q ROUTE− ‘Q’ is the designator assigned to

published RNAV routes used by the United States.

QNE− The barometric pressure used for the standard

altimeter setting (29.92 inches Hg.).

QNH− The barometric pressure as reported by a

particular station.

QUADRANT− A quarter part of a circle, centered on

a NAVAID, oriented clockwise from magnetic north

as follows: NE quadrant 000-089, SE quadrant

090-179, SW quadrant 180-269, NW quadrant

270-359.

QUEUING−

(See STAGING/QUEUING.)

QUICK LOOK− A feature of the EAS and ARTS

which provides the controller the capability to

display full data blocks of tracked aircraft from other

control positions.

Pilot/Controller Glossary

10/12/17

PCG R−1

RADAR− A device which, by measuring the time

interval between transmission and reception of radio

pulses and correlating the angular orientation of the

radiated antenna beam or beams in azimuth and/or

elevation, provides information on range, azimuth,

and/or elevation of objects in the path of the

transmitted pulses.

a. Primary Radar− A radar system in which a

minute portion of a radio pulse transmitted from a site

is reflected by an object and then received back at that

site for processing and display at an air traffic control

facility.

b. Secondary Radar/Radar Beacon (ATCRBS)− A

radar system in which the object to be detected is

fitted with cooperative equipment in the form of a

radio receiver/transmitter (transponder). Radar

pulses transmitted from the searching transmitter/re-

ceiver (interrogator) site are received in the

cooperative equipment and used to trigger a

distinctive transmission from the transponder. This

reply transmission, rather than a reflected signal, is

then received back at the transmitter/receiver site for

processing and display at an air traffic control facility.

(See INTERROGATOR.)

(See TRANSPONDER.)

(See ICAO term RADAR.)

(Refer to AIM.)

RADAR [ICAO]− A radio detection device which

provides information on range, azimuth and/or

elevation of objects.

a. Primary Radar− Radar system which uses

reflected radio signals.

b. Secondary Radar− Radar system wherein a

radio signal transmitted from a radar station initiates

the transmission of a radio signal from another

station.

RADAR ADVISORY− The provision of advice and

information based on radar observations.

(See ADVISORY SERVICE.)

RADAR ALTIMETER−

(See RADIO ALTIMETER.)

RADAR APPROACH− An instrument approach

procedure which utilizes Precision Approach Radar

(PAR) or Airport Surveillance Radar (ASR).

(See AIRPORT SURVEILLANCE RADAR.)

(See INSTRUMENT APPROACH

PROCEDURE.)

(See PRECISION APPROACH RADAR.)

(See SURVEILLANCE APPROACH.)

(See ICAO term RADAR APPROACH.)

(Refer to AIM.)

RADAR APPROACH [ICAO]− An approach,

executed by an aircraft, under the direction of a radar

controller.

RADAR APPROACH CONTROL FACILITY− A

terminal ATC facility that uses radar and nonradar

capabilities to provide approach control services to

aircraft arriving, departing, or transiting airspace

controlled by the facility.

(See APPROACH CONTROL SERVICE.)

a. Provides radar ATC services to aircraft

operating in the vicinity of one or more civil and/or

military airports in a terminal area. The facility may

provide services of a ground controlled approach

(GCA); i.e., ASR and PAR approaches. A radar

approach control facility may be operated by FAA,

USAF, US Army, USN, USMC, or jointly by FAA

and a military service. Specific facility nomencla-

tures are used for administrative purposes only and

are related to the physical location of the facility and

the operating service generally as follows:

1. Army Radar Approach Control (ARAC)

(Army).

2. Radar Air Traffic Control Facility (RATCF)

(Navy/FAA).

3. Radar Approach Control (RAPCON) (Air

Force/FAA).

4. Terminal Radar Approach Control

(TRACON) (FAA).

5. Air Traffic Control Tower (ATCT) (FAA).

(Only those towers delegated approach control

authority.)

RADAR ARRIVAL− An aircraft arriving at an

airport served by a radar facility and in radar contact

with the facility.

(See NONRADAR.)

Pilot/Controller Glossary 10/12/17

PCG R−2

RADAR BEACON−

(See RADAR.)

RADAR CLUTTER [ICAO]− The visual indication

on a radar display of unwanted signals.

RADAR CONTACT−

a. Used by ATC to inform an aircraft that it is

identified using an approved ATC surveillance

source on an air traffic controller’s display and that

radar flight following will be provided until radar

service is terminated. Radar service may also be

provided within the limits of necessity and capability.

When a pilot is informed of “radar contact,” he/she

automatically discontinues reporting over compuls-

ory reporting points.

(See ATC SURVEILLANCE SOURCE.)

(See RADAR CONTACT LOST.)

(See RADAR FLIGHT FOLLOWING.)

(See RADAR SERVICE.)

(See RADAR SERVICE TERMINATED.)

(Refer to AIM.)

b. The term used to inform the controller that the

aircraft is identified and approval is granted for the

aircraft to enter the receiving controllers airspace.

(See ICAO term RADAR CONTACT.)

RADAR CONTACT [ICAO]− The situation which

exists when the radar blip or radar position symbol of

a particular aircraft is seen and identified on a radar

display.

RADAR CONTACT LOST− Used by ATC to inform

a pilot that the surveillance data used to determine the

aircraft’s position is no longer being received, or is no

longer reliable and radar service is no longer being

provided. The loss may be attributed to several

factors including the aircraft merging with weather or

ground clutter, the aircraft operating below radar line

of sight coverage, the aircraft entering an area of poor

radar return, failure of the aircraft’s equipment, or

failure of the surveillance equipment.

(See CLUTTER.)

(See RADAR CONTACT.)

RADAR ENVIRONMENT− An area in which radar

service may be provided.

(See ADDITIONAL SERVICES.)

(See RADAR CONTACT.)

(See RADAR SERVICE.)

(See TRAFFIC ADVISORIES.)

RADAR FLIGHT FOLLOWING− The observation

of the progress of radar identified aircraft, whose

primary navigation is being provided by the pilot,

wherein the controller retains and correlates the

aircraft identity with the appropriate target or target

symbol displayed on the radar scope.

(See RADAR CONTACT.)

(See RADAR SERVICE.)

(Refer to AIM.)

RADAR IDENTIFICATION− The process of

ascertaining that an observed radar target is the radar

return from a particular aircraft.

(See RADAR CONTACT.)

(See RADAR SERVICE.)

RADAR IDENTIFIED AIRCRAFT− An aircraft, the

position of which has been correlated with an

observed target or symbol on the radar display.

(See RADAR CONTACT.)

(See RADAR CONTACT LOST.)

RADAR MONITORING−

(See RADAR SERVICE.)

RADAR NAVIGATIONAL GUIDANCE−

(See RADAR SERVICE.)

RADAR POINT OUT− An action taken by a

controller to transfer the radar identification of an

aircraft to another controller if the aircraft will or may

enter the airspace or protected airspace of another

controller and radio communications will not be

transferred.

RADAR REQUIRED− A term displayed on charts

and approach plates and included in FDC NOTAMs

to alert pilots that segments of either an instrument

approach procedure or a route are not navigable

because of either the absence or unusability of a

NAVAID. The pilot can expect to be provided radar

navigational guidance while transiting segments

labeled with this term.

(See RADAR ROUTE.)

(See RADAR SERVICE.)

RADAR ROUTE− A flight path or route over which

an aircraft is vectored. Navigational guidance and

altitude assignments are provided by ATC.

(See FLIGHT PATH.)

(See ROUTE.)

RADAR SEPARATION−

(See RADAR SERVICE.)

RADAR SERVICE− A term which encompasses one

or more of the following services based on the use of

Pilot/Controller Glossary

10/12/17

PCG R−3

radar which can be provided by a controller to a pilot

of a radar identified aircraft.

a. Radar Monitoring− The radar flight-following

of aircraft, whose primary navigation is being

performed by the pilot, to observe and note deviations

from its authorized flight path, airway, or route.

When being applied specifically to radar monitoring

of instrument approaches; i.e., with precision

approach radar (PAR) or radar monitoring of

simultaneous ILS,RNAV and GLS approaches, it

includes advice and instructions whenever an aircraft

nears or exceeds the prescribed PAR safety limit or

simultaneous ILS RNAV and GLS no transgression

zone.

(See ADDITIONAL SERVICES.)

(See TRAFFIC ADVISORIES.)

b. Radar Navigational Guidance− Vectoring

aircraft to provide course guidance.

c. Radar Separation− Radar spacing of aircraft in

accordance with established minima.

(See ICAO term RADAR SERVICE.)

RADAR SERVICE [ICAO]− Term used to indicate

a service provided directly by means of radar.

a. Monitoring− The use of radar for the purpose of

providing aircraft with information and advice

relative to significant deviations from nominal flight

path.

b. Separation− The separation used when aircraft

position information is derived from radar sources.

RADAR SERVICE TERMINATED− Used by ATC

to inform a pilot that he/she will no longer be

provided any of the services that could be received

while in radar contact. Radar service is automatically

terminated, and the pilot is not advised in the

following cases:

a. An aircraft cancels its IFR flight plan, except

within Class B airspace, Class C airspace, a TRSA,

or where Basic Radar service is provided.

b. An aircraft conducting an instrument, visual, or

contact approach has landed or has been instructed to

change to advisory frequency.

c. An arriving VFR aircraft, receiving radar

service to a tower-controlled airport within Class B

airspace, Class C airspace, a TRSA, or where

sequencing service is provided, has landed; or to all

other airports, is instructed to change to tower or

advisory frequency.

d. An aircraft completes a radar approach.

RADAR SURVEILLANCE− The radar observation

of a given geographical area for the purpose of

performing some radar function.

RADAR TRAFFIC ADVISORIES− Advisories

issued to alert pilots to known or observed radar

traffic which may affect the intended route of flight

of their aircraft.

(See TRAFFIC ADVISORIES.)

RADAR TRAFFIC INFORMATION SERVICE−

(See TRAFFIC ADVISORIES.)

RADAR VECTORING [ICAO]− Provision of

navigational guidance to aircraft in the form of

specific headings, based on the use of radar.

RADIAL− A magnetic bearing extending from a

VOR/VORTAC/TACAN navigation facility.

RADIO−

a. A device used for communication.

b. Used to refer to a flight service station; e.g.,

“Seattle Radio” is used to call Seattle FSS.

RADIO ALTIMETER− Aircraft equipment which

makes use of the reflection of radio waves from the

ground to determine the height of the aircraft above

the surface.

RADIO BEACON−

(See NONDIRECTIONAL BEACON.)

RADIO DETECTION AND RANGING−

(See RADAR.)

RADIO MAGNETIC INDICATOR− An aircraft

navigational instrument coupled with a gyro compass

or similar compass that indicates the direction of a

selected NAVAID and indicates bearing with respect

to the heading of the aircraft.

RAIS−

(See REMOTE AIRPORT INFORMATION

SERVICE.)

RAMP−

(See APRON.)

RANDOM ALTITUDE− An altitude inappropriate

for direction of flight and/or not in accordance with

FAA Order JO 7110.65, Para 4−5−1, VERTICAL

SEPARATION MINIMA.

RANDOM ROUTE− Any route not established or

charted/published or not otherwise available to all

users.

RC−

(See ROAD RECONNAISSANCE.)

Pilot/Controller Glossary 10/12/17

PCG R−4

RCAG−

(See REMOTE COMMUNICATIONS

AIR/GROUND FACILITY.)

RCC−

(See RESCUE COORDINATION CENTER.)

RCO−

(See REMOTE COMMUNICATIONS OUTLET.)

RCR−

(See RUNWAY CONDITION READING.)

READ BACK− Repeat my message back to me.

RECEIVER AUTONOMOUS INTEGRITY MON-

ITORING (RAIM)− A technique whereby a civil

GNSS receiver/processor determines the integrity of

the GNSS navigation signals without reference to

sensors or non-DoD integrity systems other than the

receiver itself. This determination is achieved by a

consistency check among redundant pseudorange

measurements.

RECEIVING CONTROLLER− A controller/facility

receiving control of an aircraft from another

controller/facility.

RECEIVING FACILITY−

(See RECEIVING CONTROLLER.)

RECONFORMANCE− The automated process of

bringing an aircraft’s Current Plan Trajectory into

conformance with its track.

REDUCE SPEED TO (SPEED)−

(See SPEED ADJUSTMENT.)

REIL−

(See RUNWAY END IDENTIFIER LIGHTS.)

RELEASE TIME− A departure time restriction

issued to a pilot by ATC (either directly or through an

authorized relay) when necessary to separate a

departing aircraft from other traffic.

(See ICAO term RELEASE TIME.)

RELEASE TIME [ICAO]− Time prior to which an

aircraft should be given further clearance or prior to

which it should not proceed in case of radio failure.

REMOTE AIRPORT INFORMATION SERVICE

(RAIS)− A temporary service provided by facilities,

which are not located on the landing airport, but have

communication capability and automated weather

reporting available to the pilot at the landing airport.

REMOTE COMMUNICATIONS AIR/GROUND

FACILITY− An unmanned VHF/UHF transmitter/

receiver facility which is used to expand ARTCC

air/ground communications coverage and to facilitate

direct contact between pilots and controllers. RCAG

facilities are sometimes not equipped with emergen-

cy frequencies 121.5 MHz and 243.0 MHz.

(Refer to AIM.)

REMOTE COMMUNICATIONS OUTLET− An

unmanned communications facility remotely con-

trolled by air traffic personnel. RCOs serve FSSs.

RTRs serve terminal ATC facilities. An RCO or RTR

may be UHF or VHF and will extend the

communication range of the air traffic facility. There

are several classes of RCOs and RTRs. The class is

determined by the number of transmitters or

receivers. Classes A through G are used primarily for

air/ground purposes. RCO and RTR class O

facilities are nonprotected outlets subject to

undetected and prolonged outages. RCO (O’s) and

RTR (O’s) were established for the express purpose

of providing ground-to-ground communications

between air traffic control specialists and pilots

located at a satellite airport for delivering en route

clearances, issuing departure authorizations, and

acknowledging instrument flight rules cancellations

or departure/landing times. As a secondary function,

they may be used for advisory purposes whenever the

aircraft is below the coverage of the primary

air/ground frequency.

REMOTE TRANSMITTER/RECEIVER−

(See REMOTE COMMUNICATIONS OUTLET.)

REPORT− Used to instruct pilots to advise ATC of

specified information; e.g., “Report passing Hamil-

ton VOR.”

REPORTING POINT− A geographical location in

relation to which the position of an aircraft is

reported.

(See COMPULSORY REPORTING POINTS.)

(See ICAO term REPORTING POINT.)

(Refer to AIM.)

REPORTING POINT [ICAO]− A specified geo-

graphical location in relation to which the position of

an aircraft can be reported.

REQUEST FULL ROUTE CLEARANCE− Used

by pilots to request that the entire route of flight be

read verbatim in an ATC clearance. Such request

should be made to preclude receiving an ATC

clearance based on the original filed flight plan when

Pilot/Controller Glossary

10/12/17

PCG R−5

a filed IFR flight plan has been revised by the pilot,

company, or operations prior to departure.

REQUIRED NAVIGATION PERFORMANCE

(RNP)– A statement of the navigational performance

necessary for operation within a defined airspace.

The following terms are commonly associated with

RNP:

a. Required Navigation Performance Level or

Type (RNP-X). A value, in nautical miles (NM), from

the intended horizontal position within which an

aircraft would be at least 95-percent of the total flying

time.

b. Required Navigation Performance (RNP)

Airspace. A generic term designating airspace, route

(s), leg (s), operation (s), or procedure (s) where

minimum required navigational performance (RNP)

have been established.

c. Actual Navigation Performance (ANP). A

measure of the current estimated navigational

performance. Also referred to as Estimated Position

Error (EPE).

d. Estimated Position Error (EPE). A measure of

the current estimated navigational performance. Also

referred to as Actual Navigation Performance (ANP).

e. Lateral Navigation (LNAV). A function of area

navigation (RNAV) equipment which calculates,

displays, and provides lateral guidance to a profile or

path.

f. Vertical Navigation (VNAV). A function of area

navigation (RNAV) equipment which calculates,

displays, and provides vertical guidance to a profile

or path.

RESCUE COORDINATION CENTER− A search

and rescue (SAR) facility equipped and manned to

coordinate and control SAR operations in an area

designated by the SAR plan. The U.S. Coast Guard

and the U.S. Air Force have responsibility for the

operation of RCCs.

(See ICAO term RESCUE CO-ORDINATION

CENTRE.)

RESCUE CO-ORDINATION CENTRE [ICAO]− A

unit responsible for promoting efficient organization

of search and rescue service and for coordinating the

conduct of search and rescue operations within a

search and rescue region.

RESOLUTION ADVISORY−A display indication

given to the pilot by the traffic alert and collision

avoidance systems (TCAS II) recommending a

maneuver to increase vertical separation relative to an

intruding aircraft. Positive, negative, and vertical

speed limit (VSL) advisories constitute the resolution

advisories. A resolution advisory is also classified as

corrective or preventive

RESTRICTED AREA−

(See SPECIAL USE AIRSPACE.)

(See ICAO term RESTRICTED AREA.)

RESTRICTED AREA [ICAO]− An airspace of

defined dimensions, above the land areas or territorial

waters of a State, within which the flight of aircraft

is restricted in accordance with certain specified

conditions.

RESUME NORMAL SPEED− Used by ATC to

advise a pilot to resume an aircraft’s normal operating

speed. It is issued to terminate a speed adjustment

where no published speed restrictions apply. It does

not delete speed restrictions in published procedures

of upcoming segments of flight. This does not relieve

the pilot of those speed restrictions, which are

applicable to 14 CFR Section 91.117.

RESUME OWN NAVIGATION− Used by ATC to

advise a pilot to resume his/her own navigational

responsibility. It is issued after completion of a radar

vector or when radar contact is lost while the aircraft

is being radar vectored.

(See RADAR CONTACT LOST.)

(See RADAR SERVICE TERMINATED.)

RESUME PUBLISHED SPEED- Used by ATC to

advise a pilot to resume published speed restrictions

that are applicable to a SID, STAR, or other

instrument procedure. It is issued to terminate a speed

adjustment where speed restrictions are published on

a charted procedure.

RMI−

(See RADIO MAGNETIC INDICATOR.)

RNAV−

(See AREA NAVIGATION (RNAV).)

RNAV APPROACH− An instrument approach

procedure which relies on aircraft area navigation

equipment for navigational guidance.

(See AREA NAVIGATION (RNAV).)

(See INSTRUMENT APPROACH

PROCEDURE.)

ROAD RECONNAISSANCE− Military activity

requiring navigation along roads, railroads, and

Pilot/Controller Glossary 10/12/17

PCG R−6

rivers. Reconnaissance route/route segments are

seldom along a straight line and normally require a

lateral route width of 10 NM to 30 NM and an altitude

range of 500 feet to 10,000 feet AGL.

ROGER− I have received all of your last

transmission. It should not be used to answer a

question requiring a yes or a no answer.

(See AFFIRMATIVE.)

(See NEGATIVE.)

ROLLOUT RVR−

(See VISIBILITY.)

ROUTE− A defined path, consisting of one or more

courses in a horizontal plane, which aircraft traverse

over the surface of the earth.

(See AIRWAY.)

(See JET ROUTE.)

(See PUBLISHED ROUTE.)

(See UNPUBLISHED ROUTE.)

ROUTE ACTION NOTIFICATION− EDST notifi-

cation that a PAR/PDR/PDAR has been applied to the

flight plan.

(See ATC PREFERRED ROUTE

NOTIFICATION.)

(See EN ROUTE DECISION SUPPORT TOOL)

ROUTE SEGMENT− As used in Air Traffic Control,

a part of a route that can be defined by two

navigational fixes, two NAVAIDs, or a fix and a

NAVAID.

(See FIX.)

(See ROUTE.)

(See ICAO term ROUTE SEGMENT.)

ROUTE SEGMENT [ICAO]− A portion of a route to

be flown, as defined by two consecutive significant

points specified in a flight plan.

RSA−

(See RUNWAY SAFETY AREA.)

RTR−

(See REMOTE TRANSMITTER/RECEIVER.)

RUNWAY− A defined rectangular area on a land

airport prepared for the landing and takeoff run of

aircraft along its length. Runways are normally

numbered in relation to their magnetic direction

rounded off to the nearest 10 degrees; e.g., Runway

1, Runway 25.

(See PARALLEL RUNWAYS.)

(See ICAO term RUNWAY.)

RUNWAY [ICAO]− A defined rectangular area on a

land aerodrome prepared for the landing and take-off

of aircraft.

RUNWAY CENTERLINE LIGHTING−

(See AIRPORT LIGHTING.)

RUNWAY CONDITION CODES (RwyCC) *

Numerical readings, provided by airport operators,

that indicate runway surface contamination (for

example, slush, ice, rain, etc.). These values range

from “1” (poor) to “6” (dry) and must be included on

the ATIS when the reportable condition is less than 6

in any one or more of the three runway zones

(touchdown, midpoint, rollout).

RUNWAY CONDITION READING− Numerical

decelerometer readings relayed by air traffic

controllers at USAF and certain civil bases for use by

the pilot in determining runway braking action.

These readings are routinely relayed only to USAF

and Air National Guard Aircraft.

(See BRAKING ACTION.)

RUNWAY CONDITION REPORT (RwyCR)− A

data collection worksheet used by airport operators

that correlates the runway percentage of coverage

along with the depth and type of contaminant for the

purpose of creating a FICON NOTAM.

(See RUNWAY CONDITION CODES)

RUNWAY END IDENTIFIER LIGHTS−

(See AIRPORT LIGHTING.)

RUNWAY ENTRANCE LIGHTS (REL)—An array

of red lights which include the first light at the hold

line followed by a series of evenly spaced lights to the

runway edge aligned with the taxiway centerline, and

one additional light at the runway centerline in line

with the last two lights before the runway edge.

RUNWAY GRADIENT− The average slope, mea-

sured in percent, between two ends or points on a

runway. Runway gradient is depicted on Government

aerodrome sketches when total runway gradient

exceeds 0.3%.

RUNWAY HEADING− The magnetic direction that

corresponds with the runway centerline extended, not

the painted runway number. When cleared to “fly or

maintain runway heading,” pilots are expected to fly

or maintain the heading that corresponds with the

extended centerline of the departure runway. Drift

correction shall not be applied; e.g., Runway 4, actual

magnetic heading of the runway centerline 044, fly

044.

Pilot/Controller Glossary

10/12/17

PCG R−7

RUNWAY IN USE/ACTIVE RUNWAY/DUTY

RUNWAY− Any runway or runways currently being

used for takeoff or landing. When multiple runways

are used, they are all considered active runways. In

the metering sense, a selectable adapted item which

specifies the landing runway configuration or

direction of traffic flow. The adapted optimum flight

plan from each transition fix to the vertex is

determined by the runway configuration for arrival

metering processing purposes.

RUNWAY LIGHTS−

(See AIRPORT LIGHTING.)

RUNWAY MARKINGS−

(See AIRPORT MARKING AIDS.)

RUNWAY OVERRUN− In military aviation exclu-

sively, a stabilized or paved area beyond the end of a

runway, of the same width as the runway plus

shoulders, centered on the extended runway

centerline.

RUNWAY PROFILE DESCENT− An instrument

flight rules (IFR) air traffic control arrival procedure

to a runway published for pilot use in graphic and/or

textual form and may be associated with a STAR.

Runway Profile Descents provide routing and may

depict crossing altitudes, speed restrictions, and

headings to be flown from the en route structure to the

point where the pilot will receive clearance for and

execute an instrument approach procedure. A

Runway Profile Descent may apply to more than one

runway if so stated on the chart.

(Refer to AIM.)

RUNWAY SAFETY AREA− A defined surface

surrounding the runway prepared, or suitable, for

reducing the risk of damage to airplanes in the event

of an undershoot, overshoot, or excursion from the

runway. The dimensions of the RSA vary and can be

determined by using the criteria contained within

AC 150/5300-13, Airport Design, Chapter 3.

Figure 3−1 in AC 150/5300-13 depicts the RSA. The

design standards dictate that the RSA shall be:

a. Cleared, graded, and have no potentially

hazardous ruts, humps, depressions, or other surface

variations;

b. Drained by grading or storm sewers to prevent

water accumulation;

c. Capable, under dry conditions, of supporting

snow removal equipment, aircraft rescue and

firefighting equipment, and the occasional passage of

aircraft without causing structural damage to the

aircraft; and,

d. Free of objects, except for objects that need to

be located in the runway safety area because of their

function. These objects shall be constructed on low

impact resistant supports (frangible mounted struc-

tures) to the lowest practical height with the frangible

point no higher than 3 inches above grade.

(Refer to AC 150/5300-13, Airport Design,

Chapter 3.)

RUNWAY STATUS LIGHTS (RWSL)

SYSTEM—The RWSL is a system of runway and

taxiway lighting to provide pilots increased

situational awareness by illuminating runway entry

lights (REL) when the runway is unsafe for entry or

crossing, and take-off hold lights (THL) when the

runway is unsafe for departure.

RUNWAY TRANSITION−

a. Conventional STARs/SIDs. The portion of a

STAR/SID that serves a particular runway or

runways at an airport.

b. RNAV STARs/SIDs. Defines a path(s) from

the common route to the final point(s) on a STAR. For

a SID, the common route that serves a particular

runway or runways at an airport.

RUNWAY USE PROGRAM− A noise abatement

runway selection plan designed to enhance noise

abatement efforts with regard to airport communities

for arriving and departing aircraft. These plans are

developed into runway use programs and apply to all

turbojet aircraft 12,500 pounds or heavier; turbojet

aircraft less than 12,500 pounds are included only if

the airport proprietor determines that the aircraft

creates a noise problem. Runway use programs are

coordinated with FAA offices, and safety criteria

used in these programs are developed by the Office of

Flight Operations. Runway use programs are

administered by the Air Traffic Service as “Formal”

or “Informal” programs.

a. Formal Runway Use Program− An approved

noise abatement program which is defined and

acknowledged in a Letter of Understanding between

Flight Operations, Air Traffic Service, the airport

proprietor, and the users. Once established, participa-

tion in the program is mandatory for aircraft operators

and pilots as provided for in 14 CFR Section 91.129.

b. Informal Runway Use Program− An approved

noise abatement program which does not require a

Pilot/Controller Glossary 10/12/17

PCG R−8

Letter of Understanding, and participation in the

program is voluntary for aircraft operators/pilots.

RUNWAY VISIBILITY VALUE−

(See VISIBILITY.)

RUNWAY VISUAL RANGE−

(See VISIBILITY.)

RwyCC−

(See RUNWAY CONDITION CODES.)

RwyCR−

(See RUNWAY CONDITION REPORT.)

Pilot/Controller Glossary

10/12/17

PCG S−1

SAA−

(See SPECIAL ACTIVITY AIRSPACE.)

SAFETY ALERT− A safety alert issued by ATC to

aircraft under their control if ATC is aware the aircraft

is at an altitude which, in the controller’s judgment,

places the aircraft in unsafe proximity to terrain,

obstructions, or other aircraft. The controller may

discontinue the issuance of further alerts if the pilot

advises he/she is taking action to correct the situation

or has the other aircraft in sight.

a. Terrain/Obstruction Alert− A safety alert issued

by ATC to aircraft under their control if ATC is aware

the aircraft is at an altitude which, in the controller’s

judgment, places the aircraft in unsafe proximity to

terrain/obstructions; e.g., “Low Altitude Alert, check

your altitude immediately.”

b. Aircraft Conflict Alert− A safety alert issued by

ATC to aircraft under their control if ATC is aware of

an aircraft that is not under their control at an altitude

which, in the controller’s judgment, places both

aircraft in unsafe proximity to each other. With the

alert, ATC will offer the pilot an alternate course of

action when feasible; e.g., “Traffic Alert, advise you

turn right heading zero niner zero or climb to eight

thousand immediately.”

Note: The issuance of a safety alert is contingent

upon the capability of the controller to have an

awareness of an unsafe condition. The course of

action provided will be predicated on other traffic

under ATC control. Once the alert is issued, it is

solely the pilot’s prerogative to determine what

course of action, if any, he/she will take.

SAFETY LOGIC SYSTEM− A software enhance-

ment to ASDE−3, ASDE−X, and ASSC, that predicts

the path of aircraft landing and/or departing, and/or

vehicular movements on runways. Visual and aural

alarms are activated when the safety logic projects a

potential collision. The Airport Movement Area

Safety System (AMASS) is a safety logic system

enhancement to the ASDE−3. The Safety Logic

System for ASDE−X and ASSC is an integral part of

the software program.

SAFETY LOGIC SYSTEM ALERTS−

a. ALERT− An actual situation involving two real

safety logic tracks (aircraft/aircraft, aircraft/vehicle,

or aircraft/other tangible object) that safety logic has

predicted will result in an imminent collision, based

upon the current set of Safety Logic parameters.

b. FALSE ALERT−

1. Alerts generated by one or more false

surface−radar targets that the system has interpreted

as real tracks and placed into safety logic.

2. Alerts in which the safety logic software did

not perform correctly, based upon the design

specifications and the current set of Safety Logic

parameters.

3. The alert is generated by surface radar targets

caused by moderate or greater precipitation.

c. NUISANCE ALERT− An alert in which one or

more of the following is true:

1. The alert is generated by a known situation

that is not considered an unsafe operation, such as

LAHSO or other approved operations.

2. The alert is generated by inaccurate secon-

dary radar data received by the Safety Logic System.

3. One or more of the aircraft involved in the

alert is not intending to use a runway (for example,

helicopter, pipeline patrol, non−Mode C overflight,

etc.).

d. VALID NON−ALERT− A situation in which

the safety logic software correctly determines that an

alert is not required, based upon the design

specifications and the current set of Safety Logic

parameters.

e. INVALID NON−ALERT− A situation in which

the safety logic software did not issue an alert when

an alert was required, based upon the design

specifications.

SAIL BACK− A maneuver during high wind

conditions (usually with power off) where float plane

movement is controlled by water rudders/opening

and closing cabin doors.

SAME DIRECTION AIRCRAFT− Aircraft are

operating in the same direction when:

a. They are following the same track in the same

direction; or

b. Their tracks are parallel and the aircraft are

flying in the same direction; or

c. Their tracks intersect at an angle of less than 45

degrees.

Pilot/Controller Glossary 10/12/17

PCG S−2

SAR−

(See SEARCH AND RESCUE.)

SAY AGAIN− Used to request a repeat of the last

transmission. Usually specifies transmission or

portion thereof not understood or received; e.g., “Say

again all after ABRAM VOR.”

SAY ALTITUDE− Used by ATC to ascertain an

aircraft’s specific altitude/flight level. When the

aircraft is climbing or descending, the pilot should

state the indicated altitude rounded to the nearest 100

feet.

SAY HEADING− Used by ATC to request an aircraft

heading. The pilot should state the actual heading of

the aircraft.

SCHEDULED TIME OF ARRIVAL (STA)− A STA

is the desired time that an aircraft should cross a

certain point (landing or metering fix). It takes other

traffic and airspace configuration into account. A

STA time shows the results of the TBFM scheduler

that has calculated an arrival time according to

parameters such as optimized spacing, aircraft

performance, and weather.

SDF−

(See SIMPLIFIED DIRECTIONAL FACILITY.)

SEA LANE− A designated portion of water outlined

by visual surface markers for and intended to be used

by aircraft designed to operate on water.

SEARCH AND RESCUE− A service which seeks

missing aircraft and assists those found to be in need

of assistance. It is a cooperative effort using the

facilities and services of available Federal, state and

local agencies. The U.S. Coast Guard is responsible

for coordination of search and rescue for the Maritime

Region, and the U.S. Air Force is responsible for

search and rescue for the Inland Region. Information

pertinent to search and rescue should be passed

through any air traffic facility or be transmitted

directly to the Rescue Coordination Center by

telephone.

(See FLIGHT SERVICE STATION.)

(See RESCUE COORDINATION CENTER.)

(Refer to AIM.)

SEARCH AND RESCUE FACILITY− A facility

responsible for maintaining and operating a search

and rescue (SAR) service to render aid to persons and

property in distress. It is any SAR unit, station, NET,

or other operational activity which can be usefully

employed during an SAR Mission; e.g., a Civil Air

Patrol Wing, or a Coast Guard Station.

(See SEARCH AND RESCUE.)

SECNOT−

(See SECURITY NOTICE.)

SECONDARY RADAR TARGET− A target derived

from a transponder return presented on a radar

display.

SECTIONAL AERONAUTICAL CHARTS−

(See AERONAUTICAL CHART.)

SECTOR LIST DROP INTERVAL− A parameter

number of minutes after the meter fix time when

arrival aircraft will be deleted from the arrival sector

list.

SECURITY NOTICE (SECNOT) − A SECNOT is a

request originated by the Air Traffic Security

Coordinator (ATSC) for an extensive communica-

tions search for aircraft involved, or suspected of

being involved, in a security violation, or are

considered a security risk. A SECNOT will include

the aircraft identification, search area, and expiration

time. The search area, as defined by the ATSC, could

be a single airport, multiple airports, a radius of an

airport or fix, or a route of flight. Once the expiration

time has been reached, the SECNOT is considered to

be cancelled.

SECURITY SERVICES AIRSPACE − Areas

established through the regulatory process or by

NOTAM, issued by the Administrator under title 14,

CFR, sections 99.7, 91.141, and 91.139, which

specify that ATC security services are required; i.e.,

ADIZ or temporary flight rules areas.

SEE AND AVOID− When weather conditions

permit, pilots operating IFR or VFR are required to

observe and maneuver to avoid other aircraft.

Right-of-way rules are contained in 14 CFR Part 91.

SEGMENTED CIRCLE− A system of visual

indicators designed to provide traffic pattern

information at airports without operating control

towers.

(Refer to AIM.)

SEGMENTS OF AN INSTRUMENT APPROACH

PROCEDURE− An instrument approach procedure

may have as many as four separate segments

depending on how the approach procedure is

structured.

a. Initial Approach− The segment between the

initial approach fix and the intermediate fix or the

Pilot/Controller Glossary

10/12/17

PCG S−3

point where the aircraft is established on the

intermediate course or final approach course.

(See ICAO term INITIAL APPROACH

SEGMENT.)

b. Intermediate Approach− The segment between

the intermediate fix or point and the final approach

fix.

(See ICAO term INTERMEDIATE APPROACH

SEGMENT.)

c. Final Approach− The segment between the final

approach fix or point and the runway, airport, or

missed approach point.

(See ICAO term FINAL APPROACH SEGMENT.)

d. Missed Approach− The segment between the

missed approach point or the point of arrival at

decision height and the missed approach fix at the

prescribed altitude.

(Refer to 14 CFR Part 97.)

(See ICAO term MISSED APPROACH

PROCEDURE.)

SEPARATION− In air traffic control, the spacing of

aircraft to achieve their safe and orderly movement in

flight and while landing and taking off.

(See SEPARATION MINIMA.)

(See ICAO term SEPARATION.)

SEPARATION [ICAO]− Spacing between aircraft,

levels or tracks.

SEPARATION MINIMA− The minimum longitudi-

nal, lateral, or vertical distances by which aircraft are

spaced through the application of air traffic control

procedures.

(See SEPARATION.)

SERVICE− A generic term that designates functions

or assistance available from or rendered by air traffic

control. For example, Class C service would denote

the ATC services provided within a Class C airspace

area.

SEVERE WEATHER AVOIDANCE PLAN− An

approved plan to minimize the affect of severe

weather on traffic flows in impacted terminal and/or

ARTCC areas. SWAP is normally implemented to

provide the least disruption to the ATC system when

flight through portions of airspace is difficult or

impossible due to severe weather.

SEVERE WEATHER FORECAST ALERTS−

Preliminary messages issued in order to alert users

that a Severe Weather Watch Bulletin (WW) is being

issued. These messages define areas of possible

severe thunderstorms or tornado activity. The

messages are unscheduled and issued as required by

the Storm Prediction Center (SPC) at Norman,

Oklahoma.

(See AIRMET.)

(See CONVECTIVE SIGMET.)

(See CWA.)

(See SIGMET.)

SFA−

(See SINGLE FREQUENCY APPROACH.)

SFO−

(See SIMULATED FLAMEOUT.)

SHF−

(See SUPER HIGH FREQUENCY.)

SHORT RANGE CLEARANCE− A clearance

issued to a departing IFR flight which authorizes IFR

flight to a specific fix short of the destination while

air traffic control facilities are coordinating and

obtaining the complete clearance.

SHORT TAKEOFF AND LANDING AIRCRAFT−

An aircraft which, at some weight within its approved

operating weight, is capable of operating from a

runway in compliance with the applicable STOL

characteristics, airworthiness, operations, noise, and

pollution standards.

(See VERTICAL TAKEOFF AND LANDING

AIRCRAFT.)

SIAP−

(See STANDARD INSTRUMENT APPROACH

PROCEDURE.)

SID−

(See STANDARD INSTRUMENT DEPARTURE.)

SIDESTEP MANEUVER− A visual maneuver

accomplished by a pilot at the completion of an

instrument approach to permit a straight-in landing

on a parallel runway not more than 1,200 feet to either

side of the runway to which the instrument approach

was conducted.

(Refer to AIM.)

SIGMET− A weather advisory issued concerning

weather significant to the safety of all aircraft.

Pilot/Controller Glossary 10/12/17

PCG S−4

SIGMET advisories cover severe and extreme

turbulence, severe icing, and widespread dust or

sandstorms that reduce visibility to less than 3 miles.

(See AIRMET.)

(See AWW.)

(See CONVECTIVE SIGMET.)

(See CWA.)

(See ICAO term SIGMET INFORMATION.)

(Refer to AIM.)

SIGMET INFORMATION [ICAO]− Information

issued by a meteorological watch office concerning

the occurrence or expected occurrence of specified

en-route weather phenomena which may affect the

safety of aircraft operations.

SIGNIFICANT METEOROLOGICAL INFOR-

MATION−

(See SIGMET.)

SIGNIFICANT POINT− A point, whether a named

intersection, a NAVAID, a fix derived from a

NAVAID(s), or geographical coordinate expressed in

degrees of latitude and longitude, which is

established for the purpose of providing separation,

as a reporting point, or to delineate a route of flight.

SIMPLIFIED DIRECTIONAL FACILITY− A

NAVAID used for nonprecision instrument

approaches. The final approach course is similar to

that of an ILS localizer except that the SDF course

may be offset from the runway, generally not more

than 3 degrees, and the course may be wider than the

localizer, resulting in a lower degree of accuracy.

(Refer to AIM.)

SIMULATED FLAMEOUT− A practice approach

by a jet aircraft (normally military) at idle thrust to a

runway. The approach may start at a runway (high

key) and may continue on a relatively high and wide

downwind leg with a continuous turn to final. It

terminates in landing or low approach. The purpose

of this approach is to simulate a flameout.

(See FLAMEOUT.)

SIMULTANEOUS CLOSE PARALLEL

APPROACHES- A simultaneous, independent

approach operation permitting ILS/RNAV/GLS

approaches to airports having parallel runways

separated by at least 3,000 feet and less than 4300 feet

between centerlines. Aircraft are permitted to pass

each other during these simultaneous operations.

Integral parts of a total system are radar, NTZ

monitoring with enhanced FMA color displays that

include aural and visual alerts and predictive aircraft

position software, communications override, ATC

procedures, an Attention All Users Page (AAUP),

PRM in the approach name, and appropriate ground

based and airborne equipment. High update rate

surveillance sensor required for certain runway or

approach course separations.

SIMULTANEOUS (CONVERGING)

DEPENDENT APPROACHES-An approach

operation permitting ILS/RNAV/GLS approaches to

runways or missed approach courses that intersect

where required minimum spacing between the

aircraft on each final approach course is required.

SIMULTANEOUS (CONVERGING)

INDEPENDENT APPROACHES- An approach

operation permitting ILS/RNAV/GLS approaches to

non-parallel runways where approach procedure

design maintains the required aircraft spacing

throughout the approach and missed approach and

hence the operations may be conducted

independently.

SIMULTANEOUS ILS APPROACHES− An

approach system permitting simultaneous ILS

approaches to airports having parallel runways

separated by at least 4,300 feet between centerlines.

Integral parts of a total system are ILS, radar,

communications, ATC procedures, and appropriate

airborne equipment.

(See PARALLEL RUNWAYS.)

(Refer to AIM.)

SIMULTANEOUS OFFSET INSTRUMENT

APPROACH (SOIA)− An instrument landing

system comprised of an ILS PRM, RNAV PRM or

GLS PRM approach to one runway and an offset

LDA PRM with glideslope or an RNAV PRM or

GLS PRM approach utilizing vertical guidance to

another where parallel runway spaced less than 3,000

feet and at least 750 feet apart. The approach courses

converge by 2.5 to 3 degrees. Simultaneous close

parallel PRM approach procedures apply up to the

point where the approach course separation becomes

3,000 feet, at the offset MAP. From the offset MAP

to the runway threshold, visual separation by the

aircraft conducting the offset approach is utilized.

(Refer to AIM)

SIMULTANEOUS (PARALLEL) DEPENDENT

APPROACHES- An approach operation permitting

ILS/RNAV/GLS approaches to adjacent parallel

runways where prescribed diagonal spacing must be

Pilot/Controller Glossary

10/12/17

PCG S−5

maintained. Aircraft are not permitted to pass each

other during simultaneous dependent operations.

Integral parts of a total system ATC procedures, and

appropriate airborne and ground based equipment.

SINGLE DIRECTION ROUTES− Preferred IFR

Routes which are sometimes depicted on high

altitude en route charts and which are normally flown

in one direction only.

(See PREFERRED IFR ROUTES.)

(Refer to CHART SUPPLEMENT U.S.)

SINGLE FREQUENCY APPROACH− A service

provided under a letter of agreement to military

single-piloted turbojet aircraft which permits use of

a single UHF frequency during approach for landing.

Pilots will not normally be required to change

frequency from the beginning of the approach to

touchdown except that pilots conducting an en route

descent are required to change frequency when

control is transferred from the air route traffic control

center to the terminal facility. The abbreviation

“SFA” in the DOD FLIP IFR Supplement under

“Communications” indicates this service is available

at an aerodrome.

SINGLE-PILOTED AIRCRAFT− A military

turbojet aircraft possessing one set of flight controls,

tandem cockpits, or two sets of flight controls but

operated by one pilot is considered single-piloted by

ATC when determining the appropriate air traffic

service to be applied.

(See SINGLE FREQUENCY APPROACH.)

SKYSPOTTER− A pilot who has received

specialized training in observing and reporting

inflight weather phenomena.

SLASH− A radar beacon reply displayed as an

elongated target.

SLDI−

(See SECTOR LIST DROP INTERVAL.)

SLOT TIME−

(See METER FIX TIME/SLOT TIME.)

SLOW TAXI− To taxi a float plane at low power or

low RPM.

SN−

(See SYSTEM STRATEGIC NAVIGATION.)

SPEAK SLOWER− Used in verbal communications

as a request to reduce speech rate.

SPECIAL ACTIVITY AIRSPACE (SAA)− Any

airspace with defined dimensions within the National

Airspace System wherein limitations may be

imposed upon aircraft operations. This airspace may

be restricted areas, prohibited areas, military

operations areas, air ATC assigned airspace, and any

other designated airspace areas. The dimensions of

this airspace are programmed into EDST and can be

designated as either active or inactive by screen entry.

Aircraft trajectories are constantly tested against the

dimensions of active areas and alerts issued to the

applicable sectors when violations are predicted.

(See EN ROUTE DECISION SUPPORT TOOL.)

SPECIAL AIR TRAFFIC RULES (SATR)− Rules

that govern procedures for conducting flights in

certain areas listed in 14 CFR Part 93. The term

“SATR” is used in the United States to describe the

rules for operations in specific areas designated in the

Code of Federal Regulations.

(Refer to 14 CFR Part 93)

SPECIAL EMERGENCY− A condition of air piracy

or other hostile act by a person(s) aboard an aircraft

which threatens the safety of the aircraft or its

passengers.

SPECIAL FLIGHT RULES AREA (SFRA)− An

area in the NAS, described in 14 CFR Part 93,

wherein the flight of aircraft is subject to special

traffic rules, unless otherwise authorized by air traffic

control. Not all areas listed in 14 CFR Part 93 are

designated SFRA, but special air traffic rules apply to

all areas described in 14 CFR Part 93.

SPECIAL INSTRUMENT APPROACH PROCE-

DURE−

(See INSTRUMENT APPROACH PROCEDURE.)

SPECIAL USE AIRSPACE− Airspace of defined

dimensions identified by an area on the surface of the

earth wherein activities must be confined because of

their nature and/or wherein limitations may be

imposed upon aircraft operations that are not a part of

those activities. Types of special use airspace are:

a. Alert Area− Airspace which may contain a high

volume of pilot training activities or an unusual type

of aerial activity, neither of which is hazardous to

aircraft. Alert Areas are depicted on aeronautical

charts for the information of nonparticipating pilots.

All activities within an Alert Area are conducted in

accordance with Federal Aviation Regulations, and

pilots of participating aircraft as well as pilots

Pilot/Controller Glossary 10/12/17

PCG S−6

transiting the area are equally responsible for

collision avoidance.

b. Controlled Firing Area− Airspace wherein

activities are conducted under conditions so

controlled as to eliminate hazards to nonparticipating

aircraft and to ensure the safety of persons and

property on the ground.

c. Military Operations Area (MOA)− A MOA is

airspace established outside of Class A airspace area

to separate or segregate certain nonhazardous

military activities from IFR traffic and to identify for

VFR traffic where these activities are conducted.

(Refer to AIM.)

d. Prohibited Area− Airspace designated under

14 CFR Part 73 within which no person may operate

an aircraft without the permission of the using

agency.

(Refer to AIM.)

(Refer to En Route Charts.)

e. Restricted Area− Airspace designated under

14 CFR Part 73, within which the flight of aircraft,

while not wholly prohibited, is subject to restriction.

Most restricted areas are designated joint use and

IFR/VFR operations in the area may be authorized by

the controlling ATC facility when it is not being

utilized by the using agency. Restricted areas are

depicted on en route charts. Where joint use is

authorized, the name of the ATC controlling facility

is also shown.

(Refer to 14 CFR Part 73.)

(Refer to AIM.)

f. Warning Area− A warning area is airspace of

defined dimensions extending from 3 nautical miles

outward from the coast of the United States, that

contains activity that may be hazardous to

nonparticipating aircraft. The purpose of such

warning area is to warn nonparticipating pilots of the

potential danger. A warning area may be located over

domestic or international waters or both.

SPECIAL VFR CONDITIONS− Meteorological

conditions that are less than those required for basic

VFR flight in Class B, C, D, or E surface areas and

in which some aircraft are permitted flight under

visual flight rules.

(See SPECIAL VFR OPERATIONS.)

(Refer to 14 CFR Part 91.)

SPECIAL VFR FLIGHT [ICAO]− A VFR flight

cleared by air traffic control to operate within Class

B, C, D, and E surface areas in metrological

conditions below VMC.

SPECIAL VFR OPERATIONS− Aircraft operating

in accordance with clearances within Class B, C, D,

and E surface areas in weather conditions less than the

basic VFR weather minima. Such operations must be

requested by the pilot and approved by ATC.

(See SPECIAL VFR CONDITIONS.)

(See ICAO term SPECIAL VFR FLIGHT.)

SPEED−

(See AIRSPEED.)

(See GROUND SPEED.)

SPEED ADJUSTMENT− An ATC procedure used to

request pilots to adjust aircraft speed to a specific

value for the purpose of providing desired spacing.

Pilots are expected to maintain a speed of plus or

minus 10 knots or 0.02 Mach number of the specified

speed. Examples of speed adjustments are:

a. “Increase/reduce speed to Mach point

(number.)”

b. “Increase/reduce speed to (speed in knots)” or

“Increase/reduce speed (number of knots) knots.”

SPEED BRAKES− Moveable aerodynamic devices

on aircraft that reduce airspeed during descent and

landing.

SPEED SEGMENTS− Portions of the arrival route

between the transition point and the vertex along the

optimum flight path for which speeds and altitudes

are specified. There is one set of arrival speed

segments adapted from each transition point to each

vertex. Each set may contain up to six segments.

SQUAWK (Mode, Code, Function)− Activate

specific modes/codes/functions on the aircraft

transponder; e.g., “Squawk three/alpha, two one zero

five, low.”

(See TRANSPONDER.)

STA−

(See SCHEDULED TIME OF ARRIVAL.)

STAGING/QUEUING− The placement, integration,

and segregation of departure aircraft in designated

movement areas of an airport by departure fix, EDCT,

and/or restriction.

STAND BY− Means the controller or pilot must

pause for a few seconds, usually to attend to other

duties of a higher priority. Also means to wait as in

“stand by for clearance.” The caller should

reestablish contact if a delay is lengthy. “Stand by” is

not an approval or denial.

Pilot/Controller Glossary

10/12/17

PCG S−7

STANDARD INSTRUMENT APPROACH PRO-

CEDURE (SIAP)−

(See INSTRUMENT APPROACH PROCEDURE.)

STANDARD INSTRUMENT DEPARTURE (SID)−

A preplanned instrument flight rule (IFR) air traffic

control (ATC) departure procedure printed for

pilot/controller use in graphic form to provide

obstacle clearance and a transition from the terminal

area to the appropriate en route structure. SIDs are

primarily designed for system enhancement to

expedite traffic flow and to reduce pilot/controller

workload. ATC clearance must always be received

prior to flying a SID.

(See IFR TAKEOFF MINIMUMS AND

DEPARTURE PROCEDURES.)

(See OBSTACLE DEPARTURE PROCEDURE.)

(Refer to AIM.)

STANDARD RATE TURN− A turn of three degrees

per second.

STANDARD TERMINAL ARRIVAL− A

preplanned instrument flight rule (IFR) air traffic

control arrival procedure published for pilot use in

graphic and/or textual form. STARs provide

transition from the en route structure to an outer fix

or an instrument approach fix/arrival waypoint in the

terminal area.

STANDARD TERMINAL ARRIVAL CHARTS−

(See AERONAUTICAL CHART.)

STANDARD TERMINAL AUTOMATION RE-

PLACEMENT SYSTEM (STARS)−

(See DTAS.)

STAR−

(See STANDARD TERMINAL ARRIVAL.)

STATE AIRCRAFT− Aircraft used in military,

customs and police service, in the exclusive service

of any government, or of any political subdivision,

thereof including the government of any state,

territory, or possession of the United States or the

District of Columbia, but not including any

government-owned aircraft engaged in carrying

persons or property for commercial purposes.

STATIC RESTRICTIONS− Those restrictions that

are usually not subject to change, fixed, in place,

and/or published.

STATIONARY RESERVATIONS− Altitude

reservations which encompass activities in a fixed

area. Stationary reservations may include activities,

such as special tests of weapons systems or

equipment, certain U.S. Navy carrier, fleet, and

anti-submarine operations, rocket, missile and drone

operations, and certain aerial refueling or similar

operations.

STEP TAXI− To taxi a float plane at full power or

high RPM.

STEP TURN− A maneuver used to put a float plane

in a planing configuration prior to entering an active

sea lane for takeoff. The STEP TURN maneuver

should only be used upon pilot request.

STEPDOWN FIX− A fix permitting additional

descent within a segment of an instrument approach

procedure by identifying a point at which a

controlling obstacle has been safely overflown.

STEREO ROUTE− A routinely used route of flight

established by users and ARTCCs identified by a

coded name; e.g., ALPHA 2. These routes minimize

flight plan handling and communications.

STOL AIRCRAFT−

(See SHORT TAKEOFF AND LANDING

AIRCRAFT.)

STOP ALTITUDE SQUAWK− Used by ATC to

inform an aircraft to turn-off the automatic altitude

reporting feature of its transponder. It is issued when

the verbally reported altitude varies 300 feet or more

from the automatic altitude report.

(See ALTITUDE READOUT.)

(See TRANSPONDER.)

STOP AND GO− A procedure wherein an aircraft

will land, make a complete stop on the runway, and

then commence a takeoff from that point.

(See LOW APPROACH.)

(See OPTION APPROACH.)

STOP BURST−

(See STOP STREAM.)

STOP BUZZER−

(See STOP STREAM.)

STOP SQUAWK (Mode or Code)− Used by ATC to

tell the pilot to turn specified functions of the aircraft

transponder off.

(See STOP ALTITUDE SQUAWK.)

(See TRANSPONDER.)

Pilot/Controller Glossary 10/12/17

PCG S−8

STOP STREAM− Used by ATC to request a pilot to

suspend electronic attack activity.

(See JAMMING.)

STOPOVER FLIGHT PLAN− A flight plan format

which permits in a single submission the filing of a

sequence of flight plans through interim full-stop

destinations to a final destination.

STOPWAY− An area beyond the takeoff runway no

less wide than the runway and centered upon the

extended centerline of the runway, able to support the

airplane during an aborted takeoff, without causing

structural damage to the airplane, and designated by

the airport authorities for use in decelerating the

airplane during an aborted takeoff.

STRAIGHT-IN APPROACH IFR− An instrument

approach wherein final approach is begun without

first having executed a procedure turn, not

necessarily completed with a straight-in landing or

made to straight-in landing minimums.

(See LANDING MINIMUMS.)

(See STRAIGHT-IN APPROACH VFR.)

(See STRAIGHT-IN LANDING.)

STRAIGHT-IN APPROACH VFR− Entry into the

traffic pattern by interception of the extended runway

centerline (final approach course) without executing

any other portion of the traffic pattern.

(See TRAFFIC PATTERN.)

STRAIGHT-IN LANDING− A landing made on a

runway aligned within 30_ of the final approach

course following completion of an instrument

approach.

(See STRAIGHT-IN APPROACH IFR.)

STRAIGHT-IN LANDING MINIMUMS−

(See LANDING MINIMUMS.)

STRAIGHT-IN MINIMUMS−

(See STRAIGHT-IN LANDING MINIMUMS.)

STRATEGIC PLANNING− Planning whereby

solutions are sought to resolve potential conflicts.

SUBSTITUTE ROUTE− A route assigned to pilots

when any part of an airway or route is unusable

because of NAVAID status. These routes consist of:

a. Substitute routes which are shown on U.S.

Government charts.

b. Routes defined by ATC as specific NAVAID

radials or courses.

c. Routes defined by ATC as direct to or between

NAVAIDs.

SUNSET AND SUNRISE− The mean solar times of

sunset and sunrise as published in the Nautical

Almanac, converted to local standard time for the

locality concerned. Within Alaska, the end of evening

civil twilight and the beginning of morning civil

twilight, as defined for each locality.

SUPPLEMENTAL WEATHER SERVICE

LOCATION− Airport facilities staffed with contract

personnel who take weather observations and

provide current local weather to pilots via telephone

or radio. (All other services are provided by the parent

FSS.)

SUPPS− Refers to ICAO Document 7030 Regional

Supplementary Procedures. SUPPS contain

procedures for each ICAO Region which are unique

to that Region and are not covered in the worldwide

provisions identified in the ICAO Air Navigation

Plan. Procedures contained in Chapter 8 are based in

part on those published in SUPPS.

SURFACE AREA− The airspace contained by the

lateral boundary of the Class B, C, D, or E airspace

designated for an airport that begins at the surface and

extends upward.

SURPIC− A description of surface vessels in the area

of a Search and Rescue incident including their

predicted positions and their characteristics.

(Refer to FAA Order JO 7110.65, Para 10−6−4,

INFLIGHT CONTINGENCIES.)

SURVEILLANCE APPROACH− An instrument

approach wherein the air traffic controller issues

instructions, for pilot compliance, based on aircraft

position in relation to the final approach course

(azimuth), and the distance (range) from the end of

the runway as displayed on the controller’s radar

scope. The controller will provide recommended

altitudes on final approach if requested by the pilot.

(Refer to AIM.)

SWAP−

(See SEVERE WEATHER AVOIDANCE PLAN.)

SWSL−

(See SUPPLEMENTAL WEATHER SERVICE

LOCATION.)

SYSTEM STRATEGIC NAVIGATION− Military

activity accomplished by navigating along a

preplanned route using internal aircraft systems to

Pilot/Controller Glossary

10/12/17

PCG S−9

maintain a desired track. This activity normally

requires a lateral route width of 10 NM and altitude

range of 1,000 feet to 6,000 feet AGL with some route

segments that permit terrain following.

Pilot/Controller Glossary

10/12/17

PCG T−1

TACAN−

(See TACTICAL AIR NAVIGATION.)

TACAN-ONLY AIRCRAFT− An aircraft, normally

military, possessing TACAN with DME but no VOR

navigational system capability. Clearances must

specify TACAN or VORTAC fixes and approaches.

TACTICAL AIR NAVIGATION− An ultra-high

frequency electronic rho-theta air navigation aid

which provides suitably equipped aircraft a

continuous indication of bearing and distance to the

TACAN station.

(See VORTAC.)

(Refer to AIM.)

TAILWIND− Any wind more than 90 degrees to the

longitudinal axis of the runway. The magnetic

direction of the runway shall be used as the basis for

determining the longitudinal axis.

TAKEOFF AREA−

(See LANDING AREA.)

TAKEOFF DISTANCE AVAILABLE (TODA)– The

takeoff run available plus the length of any remaining

runway or clearway beyond the far end of the takeoff

run available.

(See ICAO term TAKEOFF DISTANCE

AVAILABLE.)

TAKEOFF DISTANCE AVAILABLE [ICAO]− The

length of the takeoff run available plus the length of

the clearway, if provided.

TAKEOFF HOLD LIGHTS (THL)– The THL

system is composed of in-pavement lighting in a

double, longitudinal row of lights aligned either side

of the runway centerline. The lights are focused

toward the arrival end of the runway at the “line up

and wait” point, and they extend for 1,500 feet in

front of the holding aircraft. Illuminated red lights

indicate to an aircraft in position for takeoff or rolling

that it is unsafe to takeoff because the runway is

occupied or about to be occupied by an aircraft or

vehicle.

TAKEOFF ROLL − The process whereby an aircraft

is aligned with the runway centerline and the aircraft

is moving with the intent to take off. For helicopters,

this pertains to the act of becoming airborne after

departing a takeoff area.

TAKEOFF RUN AVAILABLE (TORA) – The

runway length declared available and suitable for the

ground run of an airplane taking off.

(See ICAO term TAKEOFF RUN AVAILABLE.)

TAKEOFF RUN AVAILABLE [ICAO]− The length

of runway declared available and suitable for the

ground run of an aeroplane take-off.

TARGET− The indication shown on an analog

display resulting from a primary radar return or a

radar beacon reply.

(See ASSOCIATED.)

(See DIGITAL TARGET.)

(See DIGITIZED RADAR TARGET.)

(See FUSED TARGET)

(See PRIMARY RADAR TARGET.)

(See RADAR.)

(See SECONDARY RADAR TARGET.)

(See TARGET SYMBOL.)

(See ICAO term TARGET.)

(See UNASSOCIATED.)

TARGET [ICAO]− In radar:

a. Generally, any discrete object which reflects or

retransmits energy back to the radar equipment.

b. Specifically, an object of radar search or

surveillance.

TARGET RESOLUTION− A process to ensure that

correlated radar targets do not touch. Target

resolution must be applied as follows:

a. Between the edges of two primary targets or the

edges of the ASR-9/11 primary target symbol.

b. Between the end of the beacon control slash and

the edge of a primary target.

c. Between the ends of two beacon control slashes.

Note 1: Mandatory traffic advisories and safety

alerts must be issued when this procedure is used.

Note 2: This procedure must not be used when

utilizing mosaic radar systems or multi−sensor

mode.

TARGET SYMBOL− A computer-generated indica-

tion shown on a radar display resulting from a

primary radar return or a radar beacon reply.

Pilot/Controller Glossary 10/12/17

PCG T−2

TARMAC DELAY− The holding of an aircraft on the

ground either before departure or after landing with

no opportunity for its passengers to deplane.

TARMAC DELAY AIRCRAFT− An aircraft whose

pilot−in−command has requested to taxi to the ramp,

gate, or alternate deplaning area to comply with the

Three−hour Tarmac Rule.

TARMAC DELAY REQUEST− A request by the

pilot−in−command to taxi to the ramp, gate, or

alternate deplaning location to comply with the

Three−hour Tarmac Rule.

TAS−

(See TERMINAL AUTOMATION SYSTEMS.)

TAWS−

(See TERRAIN AWARENESS WARNING

SYSTEM.)

TAXI− The movement of an airplane under its own

power on the surface of an airport (14 CFR

Section 135.100 [Note]). Also, it describes the

surface movement of helicopters equipped with

wheels.

(See AIR TAXI.)

(See HOVER TAXI.)

(Refer to 14 CFR Section 135.100.)

(Refer to AIM.)

TAXI PATTERNS− Patterns established to illustrate

the desired flow of ground traffic for the different

runways or airport areas available for use.

TCAS−

(See TRAFFIC ALERT AND COLLISION

AVOIDANCE SYSTEM.)

TCH−

(See THRESHOLD CROSSING HEIGHT.)

TCLT−

(See TENTATIVE CALCULATED LANDING

TIME.)

TDLS−

(See TERMINAL DATA LINK SYSTEM.)

TDZE−

(See TOUCHDOWN ZONE ELEVATION.)

TELEPHONE INFORMATION BRIEFING SER-

VICE− A continuous telephone recording of

meteorological and/or aeronautical information.

(Refer to AIM.)

TEMPORARY FLIGHT RESTRICTION (TFR) − A

TFR is a regulatory action issued by the FAA via the

U.S. NOTAM System, under the authority of United

States Code, Title 49. TFRs are issued within the

sovereign airspace of the United States and its

territories to restrict certain aircraft from operating

within a defined area on a temporary basis to protect

persons or property in the air or on the ground. While

not all inclusive, TFRs may be issued for disaster or

hazard situations such as: toxic gas leaks or spills,

fumes from flammable agents, aircraft accident/in-

cident sites, aviation or ground resources engaged in

wildfire suppression, or aircraft relief activities

following a disaster. TFRs may also be issued in

support of VIP movements; for reasons of national

security; or when determined necessary for the

management of air traffic in the vicinity of aerial

demonstrations or major sporting events. NAS users

or other interested parties should contact a FSS for

TFR information. Additionally, TFR information can

be found in automated briefings, NOTAM publica-

tions, and on the internet at http://www.faa.gov. The

FAA also distributes TFR information to aviation

user groups for further dissemination.

TENTATIVE CALCULATED LANDING TIME− A

projected time calculated for adapted vertex for each

arrival aircraft based upon runway configuration,

airport acceptance rate, airport arrival delay period,

and other metered arrival aircraft. This time is either

the VTA of the aircraft or the TCLT/ACLT of the

previous aircraft plus the AAI, whichever is later.

This time will be updated in response to an aircraft’s

progress and its current relationship to other arrivals.

TERMINAL AREA− A general term used to describe

airspace in which approach control service or airport

traffic control service is provided.

TERMINAL AREA FACILITY− A facility provid-

ing air traffic control service for arriving and

departing IFR, VFR, Special VFR, and on occasion

en route aircraft.

(See APPROACH CONTROL FACILITY.)

(See TOWER.)

TERMINAL AUTOMATION SYSTEMS (TAS)−

TAS is used to identify the numerous automated

tracking systems including ARTS IIE, ARTS IIIA,

ARTS IIIE, STARS, and MEARTS.

TERMINAL DATA LINK SYSTEM (TDLS)− A

system that provides Digital Automatic Terminal

Information Service (D−ATIS) both on a specified

Pilot/Controller Glossary

10/12/17

PCG T−3

radio frequency and also, for subscribers, in a text

message via data link to the cockpit or to a gate

printer. TDLS also provides Pre−departure Clear-

ances (PDC), at selected airports, to subscribers,

through a service provider, in text to the cockpit or to

a gate printer. In addition, TDLS will emulate the

Flight Data Input/Output (FDIO) information within

the control tower.

TERMINAL RADAR SERVICE AREA− Airspace

surrounding designated airports wherein ATC

provides radar vectoring, sequencing, and separation

on a full-time basis for all IFR and participating VFR

aircraft. The AIM contains an explanation of TRSA.

TRSAs are depicted on VFR aeronautical charts.

Pilot participation is urged but is not mandatory.

TERMINAL VFR RADAR SERVICE− A national

program instituted to extend the terminal radar

services provided instrument flight rules (IFR)

aircraft to visual flight rules (VFR) aircraft. The

program is divided into four types service referred to

as basic radar service, terminal radar service area

(TRSA) service, Class B service and Class C service.

The type of service provided at a particular location

is contained in the Chart Supplement U.S.

a. Basic Radar Service− These services are

provided for VFR aircraft by all commissioned

terminal radar facilities. Basic radar service includes

safety alerts, traffic advisories, limited radar

vectoring when requested by the pilot, and

sequencing at locations where procedures have been

established for this purpose and/or when covered by

a letter of agreement. The purpose of this service is to

adjust the flow of arriving IFR and VFR aircraft into

the traffic pattern in a safe and orderly manner and to

provide traffic advisories to departing VFR aircraft.

b. TRSA Service− This service provides, in

addition to basic radar service, sequencing of all IFR

and participating VFR aircraft to the primary airport

and separation between all participating VFR

aircraft. The purpose of this service is to provide

separation between all participating VFR aircraft and

all IFR aircraft operating within the area defined as a

TRSA.

c. Class C Service− This service provides, in

addition to basic radar service, approved separation

between IFR and VFR aircraft, and sequencing of

VFR aircraft, and sequencing of VFR arrivals to the

primary airport.

d. Class B Service− This service provides, in

addition to basic radar service, approved separation

of aircraft based on IFR, VFR, and/or weight, and

sequencing of VFR arrivals to the primary airport(s).

(See CONTROLLED AIRSPACE.)

(See TERMINAL RADAR SERVICE AREA.)

(Refer to AIM.)

(Refer to CHART SUPPLEMENT U.S.)

TERMINAL-VERY HIGH FREQUENCY OMNI-

DIRECTIONAL RANGE STATION− A very high

frequency terminal omnirange station located on or

near an airport and used as an approach aid.

(See NAVIGATIONAL AID.)

(See VOR.)

TERRAIN AWARENESS WARNING SYSTEM

(TAWS)− An on−board, terrain proximity alerting

system providing the aircrew ‘Low Altitude

warnings’ to allow immediate pilot action.

TERRAIN FOLLOWING− The flight of a military

aircraft maintaining a constant AGL altitude above

the terrain or the highest obstruction. The altitude of

the aircraft will constantly change with the varying

terrain and/or obstruction.

TETRAHEDRON− A device normally located on

uncontrolled airports and used as a landing direction

indicator. The small end of a tetrahedron points in the

direction of landing. At controlled airports, the

tetrahedron, if installed, should be disregarded

because tower instructions supersede the indicator.

(See SEGMENTED CIRCLE.)

(Refer to AIM.)

TF−

(See TERRAIN FOLLOWING.)

THAT IS CORRECT− The understanding you have

is right.

THREE−HOUR TARMAC RULE– Rule that relates

to Department of Transportation (DOT) requirements

placed on airlines when tarmac delays are anticipated

to reach 3 hours.

360 OVERHEAD−

(See OVERHEAD MANEUVER.)

THRESHOLD− The beginning of that portion of the

runway usable for landing.

(See AIRPORT LIGHTING.)

(See DISPLACED THRESHOLD.)

THRESHOLD CROSSING HEIGHT− The

theoretical height above the runway threshold at

Pilot/Controller Glossary 10/12/17

PCG T−4

which the aircraft’s glideslope antenna would be if

the aircraft maintains the trajectory established by the

mean ILS glideslope or the altitude at which the

calculated glidepath of an RNAV or GPS approaches.

(See GLIDESLOPE.)

(See THRESHOLD.)

THRESHOLD LIGHTS−

(See AIRPORT LIGHTING.)

TIBS−

(See TELEPHONE INFORMATION BRIEFING

SERVICE.)

TIE-IN FACILITY– The FSS primarily responsible

for providing FSS services, including telecommu-

nications services for landing facilities or

navigational aids located within the boundaries of a

flight plan area (FPA). Three-letter identifiers are

assigned to each FSS/FPA and are annotated as tie-in

facilities in the Chart Supplement U.S., the Alaska

Supplement, the Pacific Supplement, and FAA Order

JO 7350.9, Location Identifiers. Large consolidated

FSS facilities may have many tie-in facilities or FSS

sectors within one facility.

(See FLIGHT PLAN AREA.)

(See FLIGHT SERVICE STATION.)

TIME BASED FLOW MANAGEMENT (TBFM)−

The hardware, software, methods, processes, and

initiatives to manage air traffic flows based on time

to balance air traffic demand with system capacity,

and support the management of PBN. This includes,

but not limited to, Adjacent Center Metering (ACM).

En Route Departure Capability (EDC),

Ground-Interval Management-Spacing (GIM-S),

Integrated Departure/Arrival Capability (IDAC),

Single Center Metering (SCM), Time-Based

Metering (TBM), Time-Based Scheduling (TBS),

and Extended/Coupled Metering.

TIME GROUP− Four digits representing the hour

and minutes from the Coordinated Universal Time

(UTC) clock. FAA uses UTC for all operations. The

term “ZULU” may be used to denote UTC. The word

“local” or the time zone equivalent shall be used to

denote local when local time is given during radio and

telephone communications. When written, a time

zone designator is used to indicate local time; e.g.

“0205M” (Mountain). The local time may be based

on the 24-hour clock system. The day begins at 0000

and ends at 2359.

TIS−B−

(See TRAFFIC INFORMATION

SERVICE−BROADCAST.)

TMPA−

(See TRAFFIC MANAGEMENT PROGRAM

ALERT.)

TMU−

(See TRAFFIC MANAGEMENT UNIT.)

TODA−

(See TAKEOFF DISTANCE AVAILABLE.)

(See ICAO term TAKEOFF DISTANCE

AVAILABLE.)

TOI−

(See TRACK OF INTEREST.)

TOP ALTITUDE– In reference to SID published

altitude restrictions the charted

“maintain” altitude

contained in the procedure description or assigned by

ATC.

TORA−

(See TAKEOFF RUN AVAILABLE.)

(See ICAO term TAKEOFF RUN AVAILABLE.)

TORCHING− The burning of fuel at the end of an

exhaust pipe or stack of a reciprocating aircraft

engine, the result of an excessive richness in the fuel

air mixture.

TOS−

(See TRAJECTORY OPTIONS SET)

TOTAL ESTIMATED ELAPSED TIME [ICAO]−

For IFR flights, the estimated time required from

take-off to arrive over that designated point, defined

by reference to navigation aids, from which it is

intended that an instrument approach procedure will

be commenced, or, if no navigation aid is associated

with the destination aerodrome, to arrive over the

destination aerodrome. For VFR flights, the

estimated time required from take-off to arrive over

the destination aerodrome.

(See ICAO term ESTIMATED ELAPSED TIME.)

TOUCH-AND-GO− An operation by an aircraft that

lands and departs on a runway without stopping or

exiting the runway.

TOUCH-AND-GO LANDING−

(See TOUCH-AND-GO.)

TOUCHDOWN−

a. The point at which an aircraft first makes

contact with the landing surface.

Pilot/Controller Glossary

10/12/17

PCG T−5

b. Concerning a precision radar approach (PAR),

it is the point where the glide path intercepts the

landing surface.

(See ICAO term TOUCHDOWN.)

TOUCHDOWN [ICAO]− The point where the

nominal glide path intercepts the runway.

Note: Touchdown as defined above is only a datum

and is not necessarily the actual point at which the

aircraft will touch the runway.

TOUCHDOWN RVR−

(See VISIBILITY.)

TOUCHDOWN ZONE− The first 3,000 feet of the

runway beginning at the threshold. The area is used

for determination of Touchdown Zone Elevation in

the development of straight-in landing minimums for

instrument approaches.

(See ICAO term TOUCHDOWN ZONE.)

TOUCHDOWN ZONE [ICAO]− The portion of a

runway, beyond the threshold, where it is intended

landing aircraft first contact the runway.

TOUCHDOWN ZONE ELEVATION− The highest

elevation in the first 3,000 feet of the landing surface.

TDZE is indicated on the instrument approach

procedure chart when straight-in landing minimums

are authorized.

(See TOUCHDOWN ZONE.)

TOUCHDOWN ZONE LIGHTING−

(See AIRPORT LIGHTING.)

TOWER− A terminal facility that uses air/ground

communications, visual signaling, and other devices

to provide ATC services to aircraft operating in the

vicinity of an airport or on the movement area.

Authorizes aircraft to land or takeoff at the airport

controlled by the tower or to transit the Class D

airspace area regardless of flight plan or weather

conditions (IFR or VFR). A tower may also provide

approach control services (radar or nonradar).

(See AIRPORT TRAFFIC CONTROL SERVICE.)

(See APPROACH CONTROL FACILITY.)

(See APPROACH CONTROL SERVICE.)

(See MOVEMENT AREA.)

(See TOWER EN ROUTE CONTROL

SERVICE.)

(See ICAO term AERODROME CONTROL

TOWER.)

(Refer to AIM.)

TOWER EN ROUTE CONTROL SERVICE− The

control of IFR en route traffic within delegated

airspace between two or more adjacent approach

control facilities. This service is designed to expedite

traffic and reduce control and pilot communication

requirements.

TOWER TO TOWER−

(See TOWER EN ROUTE CONTROL

SERVICE.)

TRACEABLE PRESSURE STANDARD− The

facility station pressure instrument, with certifica-

tion/calibration traceable to the National Institute of

Standards and Technology. Traceable pressure

standards may be mercurial barometers, commis-

sioned ASOS/AWSS or dual transducer AWOS, or

portable pressure standards or DASI.

TRACK− The actual flight path of an aircraft over the

surface of the earth.

(See COURSE.)

(See FLIGHT PATH.)

(See ROUTE.)

(See ICAO term TRACK.)

TRACK [ICAO]− The projection on the earth’s

surface of the path of an aircraft, the direction of

which path at any point is usually expressed in

degrees from North (True, Magnetic, or Grid).

TRACK OF INTEREST (TOI)− Displayed data

representing an airborne object that threatens or has

the potential to threaten North America or National

Security. Indicators may include, but are not limited

to: noncompliance with air traffic control instructions

or aviation regulations; extended loss of communica-

tions; unusual transmissions or unusual flight

behavior; unauthorized intrusion into controlled

airspace or an ADIZ; noncompliance with issued

flight restrictions/security procedures; or unlawful

interference with airborne flight crews, up to and

including hijack. In certain circumstances, an object

may become a TOI based on specific and credible

intelligence pertaining to that particular aircraft/

object, its passengers, or its cargo.

TRACK OF INTEREST RESOLUTION− A TOI

will normally be considered resolved when: the

aircraft/object is no longer airborne; the aircraft

complies with air traffic control instructions, aviation

regulations, and/or issued flight restrictions/security

procedures; radio contact is re−established and

authorized control of the aircraft is verified; the

aircraft is intercepted and intent is verified to be

Pilot/Controller Glossary 10/12/17

PCG T−6

nonthreatening/nonhostile; TOI was identified based

on specific and credible intelligence that was later

determined to be invalid or unreliable; or displayed

data is identified and characterized as invalid.

TRAFFIC−

a. A term used by a controller to transfer radar

identification of an aircraft to another controller for

the purpose of coordinating separation action. Traffic

is normally issued:

1. In response to a handoff or point out,

2. In anticipation of a handoff or point out, or

3. In conjunction with a request for control of an

aircraft.

b. A term used by ATC to refer to one or more

aircraft.

TRAFFIC ADVISORIES− Advisories issued to alert

pilots to other known or observed air traffic which

may be in such proximity to the position or intended

route of flight of their aircraft to warrant their

attention. Such advisories may be based on:

a. Visual observation.

b. Observation of radar identified and nonidenti-

fied aircraft targets on an ATC radar display, or

c. Verbal reports from pilots or other facilities.

Note 1: The word “traffic” followed by additional

information, if known, is used to provide such

advisories; e.g., “Traffic, 2 o’clock, one zero miles,

southbound, eight thousand.”

Note 2: Traffic advisory service will be provided to

the extent possible depending on higher priority

duties of the controller or other limitations; e.g.,

radar limitations, volume of traffic, frequency

congestion, or controller workload. Radar/

nonradar traffic advisories do not relieve the pilot

of his/her responsibility to see and avoid other

aircraft. Pilots are cautioned that there are many

times when the controller is not able to give traffic

advisories concerning all traffic in the aircraft’s

proximity; in other words, when a pilot requests or

is receiving traffic advisories, he/she should not

assume that all traffic will be issued.

(Refer to AIM.)

TRAFFIC ALERT (aircraft call sign), TURN

(left/right) IMMEDIATELY, (climb/descend) AND

MAINTAIN (altitude).

(See SAFETY ALERT.)

TRAFFIC ALERT AND COLLISION AVOID-

ANCE SYSTEM− An airborne collision avoidance

system based on radar beacon signals which operates

independent of ground-based equipment. TCAS-I

generates traffic advisories only. TCAS-II generates

traffic advisories, and resolution (collision avoid-

ance) advisories in the vertical plane.

TRAFFIC INFORMATION−

(See TRAFFIC ADVISORIES.)

TRAFFIC INFORMATION SERVICE−

BROADCAST (TIS−B)− The broadcast of ATC

derived traffic information to ADS−B equipped

(1090ES or UAT) aircraft. The source of this traffic

information is derived from ground−based air traffic

surveillance sensors, typically from radar targets.

TIS−B service will be available throughout the NAS

where there are both adequate surveillance coverage

(radar) and adequate broadcast coverage from

ADS−B ground stations. Loss of TIS−B will occur

when an aircraft enters an area not covered by the

GBT network. If this occurs in an area with adequate

surveillance coverage (radar), nearby aircraft that

remain within the adequate broadcast coverage

(ADS−B) area will view the first aircraft. TIS−B may

continue when an aircraft enters an area with

inadequate surveillance coverage (radar); nearby

aircraft that remain within the adequate broadcast

coverage (ADS−B) area will not view the first

aircraft.

TRAFFIC IN SIGHT− Used by pilots to inform a

controller that previously issued traffic is in sight.

(See NEGATIVE CONTACT.)

(See TRAFFIC ADVISORIES.)

TRAFFIC MANAGEMENT PROGRAM ALERT−

A term used in a Notice to Airmen (NOTAM) issued

in conjunction with a special traffic management

program to alert pilots to the existence of the program

and to refer them to either the Notices to Airmen

publication or a special traffic management program

advisory message for program details. The contrac-

tion TMPA is used in NOTAM text.

TRAFFIC MANAGEMENT UNIT− The entity in

ARTCCs and designated terminals directly involved

in the active management of facility traffic. Usually

under the direct supervision of an assistant manager

for traffic management.

TRAFFIC NO FACTOR− Indicates that the traffic

described in a previously issued traffic advisory is no

factor.

TRAFFIC NO LONGER OBSERVED− Indicates

that the traffic described in a previously issued traffic

Pilot/Controller Glossary

10/12/17

PCG T−7

advisory is no longer depicted on radar, but may still

be a factor.

TRAFFIC PATTERN− The traffic flow that is

prescribed for aircraft landing at, taxiing on, or taking

off from an airport. The components of a typical

traffic pattern are upwind leg, crosswind leg,

downwind leg, base leg, and final approach.

a. Upwind Leg− A flight path parallel to the

landing runway in the direction of landing.

b. Crosswind Leg− A flight path at right angles to

the landing runway off its upwind end.

c. Downwind Leg− A flight path parallel to the

landing runway in the direction opposite to landing.

The downwind leg normally extends between the

crosswind leg and the base leg.

d. Base Leg− A flight path at right angles to the

landing runway off its approach end. The base leg

normally extends from the downwind leg to the

intersection of the extended runway centerline.

e. Final Approach. A flight path in the direction of

landing along the extended runway centerline. The

final approach normally extends from the base leg to

the runway. An aircraft making a straight-in approach

VFR is also considered to be on final approach.

(See STRAIGHT-IN APPROACH VFR.)

(See TAXI PATTERNS.)

(See ICAO term AERODROME TRAFFIC

CIRCUIT.)

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

TRAFFIC SITUATION DISPLAY (TSD)− TSD is a

computer system that receives radar track data from

all 20 CONUS ARTCCs, organizes this data into a

mosaic display, and presents it on a computer screen.

The display allows the traffic management coordina-

tor multiple methods of selection and highlighting of

individual aircraft or groups of aircraft. The user has

the option of superimposing these aircraft positions

over any number of background displays. These

background options include ARTCC boundaries, any

stratum of en route sector boundaries, fixes, airways,

military and other special use airspace, airports, and

geopolitical boundaries. By using the TSD, a

coordinator can monitor any number of traffic

situations or the entire systemwide traffic flows.

TRAJECTORY− A EDST representation of the path

an aircraft is predicted to fly based upon a Current

Plan or Trial Plan.

(See EN ROUTE DECISION SUPPORT TOOL.)

TRAJECTORY MODELING− The automated pro-

cess of calculating a trajectory.

TRAJECTORY OPTIONS SET (TOS)- A TOS is an

electronic message, submitted by the operator, that is

used by the Collaborative Trajectory Options

Program (CTOP) to manage the airspace captured in

the traffic management program. The TOS will allow

the operator to express the route and delay trade-off

options that they are willing to accept.

TRANSCRIBED WEATHER BROADCAST− A

continuous recording of meteorological and aeronau-

tical information that is broadcast on L/MF and VOR

facilities for pilots. (Provided only in Alaska.)

(Refer to AIM.)

TRANSFER OF CONTROL− That action whereby

the responsibility for the separation of an aircraft is

transferred from one controller to another.

(See ICAO term TRANSFER OF CONTROL.)

TRANSFER OF CONTROL [ICAO]− Transfer of

responsibility for providing air traffic control service.

TRANSFERRING CONTROLLER− A controller/

facility transferring control of an aircraft to another

controller/facility.

(See ICAO term TRANSFERRING

UNIT/CONTROLLER.)

TRANSFERRING FACILITY−

(See TRANSFERRING CONTROLLER.)

TRANSFERRING UNIT/CONTROLLER [ICAO]−

Air traffic control unit/air traffic controller in the

process of transferring the responsibility for

providing air traffic control service to an aircraft to

the next air traffic control unit/air traffic controller

along the route of flight.

Note: See definition of accepting unit/controller.

TRANSITION−

a. The general term that describes the change from

one phase of flight or flight condition to another; e.g.,

transition from en route flight to the approach or

transition from instrument flight to visual flight.

b. A published procedure (DP Transition) used to

connect the basic DP to one of several en route

airways/jet routes, or a published procedure (STAR

Pilot/Controller Glossary 10/12/17

PCG T−8

Transition) used to connect one of several en route

airways/jet routes to the basic STAR.

(Refer to DP/STAR Charts.)

TRANSITION POINT− A point at an adapted

number of miles from the vertex at which an arrival

aircraft would normally commence descent from its

en route altitude. This is the first fix adapted on the

arrival speed segments.

TRANSITION WAYPOINT− The waypoint that

defines the beginning of a runway or en route

transition on an RNAV SID or STAR.

TRANSITIONAL AIRSPACE− That portion of

controlled airspace wherein aircraft change from one

phase of flight or flight condition to another.

TRANSMISSOMETER− An apparatus used to

determine visibility by measuring the transmission of

light through the atmosphere. It is the measurement

source for determining runway visual range (RVR)

and runway visibility value (RVV).

(See VISIBILITY.)

TRANSMITTING IN THE BLIND− A transmis-

sion from one station to other stations in

circumstances where two-way communication

cannot be established, but where it is believed that the

called stations may be able to receive the

transmission.

TRANSPONDER− The airborne radar beacon

receiver/transmitter portion of the Air Traffic Control

Radar Beacon System (ATCRBS) which automati-

cally receives radio signals from interrogators on the

ground, and selectively replies with a specific reply

pulse or pulse group only to those interrogations

being received on the mode to which it is set to

respond.

(See INTERROGATOR.)

(See ICAO term TRANSPONDER.)

(Refer to AIM.)

TRANSPONDER [ICAO]− A receiver/transmitter

which will generate a reply signal upon proper

interrogation; the interrogation and reply being on

different frequencies.

TRANSPONDER CODES−

(See CODES.)

TRANSPONDER OBSERVED − Phraseology used

to inform a VFR pilot the aircraft’s assigned beacon

code and position have been observed. Specifically,

this term conveys to a VFR pilot the transponder

reply has been observed and its position correlated for

transit through the designated area.

TRIAL PLAN− A proposed amendment which

utilizes automation to analyze and display potential

conflicts along the predicted trajectory of the selected

aircraft.

TRSA−

(See TERMINAL RADAR SERVICE AREA.)

TSD−

(See TRAFFIC SITUATION DISPLAY.)

TURBOJET AIRCRAFT− An aircraft having a jet

engine in which the energy of the jet operates a

turbine which in turn operates the air compressor.

TURBOPROP AIRCRAFT− An aircraft having a jet

engine in which the energy of the jet operates a

turbine which drives the propeller.

TURN ANTICIPATION− (maneuver anticipation).

TVOR−

(See TERMINAL-VERY HIGH FREQUENCY

OMNIDIRECTIONAL RANGE STATION.)

TWEB−

(See TRANSCRIBED WEATHER BROADCAST.)

TWO-WAY RADIO COMMUNICATIONS FAIL-

URE−

(See LOST COMMUNICATIONS.)

Pilot/Controller Glossary

10/12/17

PCG U−1

UHF−

(See ULTRAHIGH FREQUENCY.)

ULTRAHIGH FREQUENCY− The frequency band

between 300 and 3,000 MHz. The bank of radio

frequencies used for military air/ground voice

communications. In some instances this may go as

low as 225 MHz and still be referred to as UHF.

ULTRALIGHT VEHICLE− A single-occupant

aeronautical vehicle operated for sport or recreational

purposes which does not require FAA registration, an

airworthiness certificate, nor pilot certification.

Operation of an ultralight vehicle in certain airspace

requires authorization from ATC

(Refer to 14 CFR Part 103.)

UNABLE− Indicates inability to comply with a

specific instruction, request, or clearance.

UNASSOCIATED− A radar target that does not

display a data block with flight identification and

altitude information.

(See ASSOCIATED.)

UNDER THE HOOD− Indicates that the pilot is

using a hood to restrict visibility outside the cockpit

while simulating instrument flight. An appropriately

rated pilot is required in the other control seat while

this operation is being conducted.

(Refer to 14 CFR Part 91.)

UNFROZEN− The Scheduled Time of Arrival (STA)

tags, which are still being rescheduled by the time

based flow management (TBFM) calculations. The

aircraft will remain unfrozen until the time the

corresponding estimated time of arrival (ETA) tag

passes the preset freeze horizon for that aircraft’s

stream class. At this point the automatic rescheduling

will stop, and the STA becomes “frozen.”

UNICOM− A nongovernment communication facil-

ity which may provide airport information at certain

airports. Locations and frequencies of UNICOMs are

shown on aeronautical charts and publications.

(See CHART SUPPLEMENT U.S.)

(Refer to AIM.)

UNMANNED AIRCRAFT (UA) - A device used or

intended to be used for flight that has no onboard

pilot. This device can be any type of airplane,

helicopter, airship, or powered-lift aircraft.

Unmanned free balloons, moored balloons, tethered

aircraft, gliders, and unmanned rockets are not

considered to be a UA.

UNMANNED AIRCRAFT SYSTEM (UAS)- An

unmanned aircraft and its associated elements related

to safe operations, which may include control

stations (ground, ship, or air based), control links,

support equipment, payloads, flight termination

systems, and launch/recovery equipment. It consists

of three elements: unmanned aircraft, control station,

and data link.

UNPUBLISHED ROUTE− A route for which no

minimum altitude is published or charted for pilot

use. It may include a direct route between NAVAIDs,

a radial, a radar vector, or a final approach course

beyond the segments of an instrument approach

procedure.

(See PUBLISHED ROUTE.)

(See ROUTE.)

UNRELIABLE (GPS/WAAS)− An advisory to

pilots indicating the expected level of service of the

GPS and/or WAAS may not be available. Pilots must

then determine the adequacy of the signal for desired

use.

UPWIND LEG−

(See TRAFFIC PATTERN.)

URGENCY− A condition of being concerned about

safety and of requiring timely but not immediate

assistance; a potential distress condition.

(See ICAO term URGENCY.)

URGENCY [ICAO]− A condition concerning the

safety of an aircraft or other vehicle, or of person on

board or in sight, but which does not require

immediate assistance.

USAFIB−

(See ARMY AVIATION FLIGHT INFORMATION

BULLETIN.)

Pilot/Controller Glossary

10/12/17

PCG V−1

VASI−

(See VISUAL APPROACH SLOPE INDICATOR.)

VCOA−

(See VISUAL CLIMB OVER AIRPORT.)

VDP−

(See VISUAL DESCENT POINT.)

VECTOR− A heading issued to an aircraft to provide

navigational guidance by radar.

(See ICAO term RADAR VECTORING.)

VERIFY− Request confirmation of information;

e.g., “verify assigned altitude.”

VERIFY SPECIFIC DIRECTION OF TAKEOFF

(OR TURNS AFTER TAKEOFF)− Used by ATC to

ascertain an aircraft’s direction of takeoff and/or

direction of turn after takeoff. It is normally used for

IFR departures from an airport not having a control

tower. When direct communication with the pilot is

not possible, the request and information may be

relayed through an FSS, dispatcher, or by other

means.

(See IFR TAKEOFF MINIMUMS AND

DEPARTURE PROCEDURES.)

VERTEX− The last fix adapted on the arrival speed

segments. Normally, it will be the outer marker of the

runway in use. However, it may be the actual

threshold or other suitable common point on the

approach path for the particular runway configura-

tion.

VERTEX TIME OF ARRIVAL− A calculated time of

aircraft arrival over the adapted vertex for the runway

configuration in use. The time is calculated via the

optimum flight path using adapted speed segments.

VERTICAL NAVIGATION (VNAV)– A function of

area navigation (RNAV) equipment which calculates,

displays, and provides vertical guidance to a profile

or path.

VERTICAL SEPARATION− Separation between

aircraft expressed in units of vertical distance.

(See SEPARATION.)

VERTICAL TAKEOFF AND LANDING AIR-

CRAFT− Aircraft capable of vertical climbs and/or

descents and of using very short runways or small

areas for takeoff and landings. These aircraft include,

but are not limited to, helicopters.

(See SHORT TAKEOFF AND LANDING

AIRCRAFT.)

VERY HIGH FREQUENCY− The frequency band

between 30 and 300 MHz. Portions of this band, 108

to 118 MHz, are used for certain NAVAIDs; 118 to

136 MHz are used for civil air/ground voice

communications. Other frequencies in this band are

used for purposes not related to air traffic control.

VERY HIGH FREQUENCY OMNIDIRECTION-

AL RANGE STATION−

(See VOR.)

VERY LOW FREQUENCY− The frequency band

between 3 and 30 kHz.

VFR−

(See VISUAL FLIGHT RULES.)

VFR AIRCRAFT− An aircraft conducting flight in

accordance with visual flight rules.

(See VISUAL FLIGHT RULES.)

VFR CONDITIONS− Weather conditions equal to

or better than the minimum for flight under visual

flight rules. The term may be used as an ATC

clearance/instruction only when:

a. An IFR aircraft requests a climb/descent in

VFR conditions.

b. The clearance will result in noise abatement

benefits where part of the IFR departure route does

not conform to an FAA approved noise abatement

route or altitude.

c. A pilot has requested a practice instrument

approach and is not on an IFR flight plan.

Note: All pilots receiving this authorization must

comply with the VFR visibility and distance from

cloud criteria in 14 CFR Part 91. Use of the term

does not relieve controllers of their responsibility to

separate aircraft in Class B and Class C airspace

or TRSAs as required by FAA Order JO 7110.65.

When used as an ATC clearance/instruction, the

term may be abbreviated “VFR;” e.g., “MAINTAIN

VFR,” “CLIMB/DESCEND VFR,” etc.

VFR FLIGHT−

(See VFR AIRCRAFT.)

Pilot/Controller Glossary 10/12/17

PCG V−2

VFR MILITARY TRAINING ROUTES− Routes

used by the Department of Defense and associated

Reserve and Air Guard units for the purpose of

conducting low-altitude navigation and tactical

training under VFR below 10,000 feet MSL at

airspeeds in excess of 250 knots IAS.

VFR NOT RECOMMENDED− An advisory

provided by a flight service station to a pilot during

a preflight or inflight weather briefing that flight

under visual flight rules is not recommended. To be

given when the current and/or forecast weather

conditions are at or below VFR minimums. It does

not abrogate the pilot’s authority to make his/her own

decision.

VFR-ON-TOP− ATC authorization for an IFR

aircraft to operate in VFR conditions at any

appropriate VFR altitude (as specified in 14 CFR and

as restricted by ATC). A pilot receiving this

authorization must comply with the VFR visibility,

distance from cloud criteria, and the minimum IFR

altitudes specified in 14 CFR Part 91. The use of this

term does not relieve controllers of their responsibil-

ity to separate aircraft in Class B and Class C airspace

or TRSAs as required by FAAO JO 7110.65.

VFR TERMINAL AREA CHARTS−

(See AERONAUTICAL CHART.)

VFR WAYPOINT−

(See WAYPOINT.)

VHF−

(See VERY HIGH FREQUENCY.)

VHF OMNIDIRECTIONAL RANGE/TACTICAL

AIR NAVIGATION−

(See VORTAC.)

VIDEO MAP− An electronically displayed map on

the radar display that may depict data such as airports,

heliports, runway centerline extensions, hospital

emergency landing areas, NAVAIDs and fixes,

reporting points, airway/route centerlines, bound-

aries, handoff points, special use tracks, obstructions,

prominent geographic features, map alignment

indicators, range accuracy marks, minimum vector-

ing altitudes.

VISIBILITY− The ability, as determined by

atmospheric conditions and expressed in units of

distance, to see and identify prominent unlighted

objects by day and prominent lighted objects by

night. Visibility is reported as statute miles, hundreds

of feet or meters.

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

a. Flight Visibility− The average forward horizon-

tal distance, from the cockpit of an aircraft in flight,

at which prominent unlighted objects may be seen

and identified by day and prominent lighted objects

may be seen and identified by night.

b. Ground Visibility− Prevailing horizontal visi-

bility near the earth’s surface as reported by the

United States National Weather Service or an

accredited observer.

c. Prevailing Visibility− The greatest horizontal

visibility equaled or exceeded throughout at least half

the horizon circle which need not necessarily be

continuous.

d. Runway Visibility Value (RVV)− The visibility

determined for a particular runway by a transmis-

someter. A meter provides a continuous indication of

the visibility (reported in miles or fractions of miles)

for the runway. RVV is used in lieu of prevailing

visibility in determining minimums for a particular

runway.

e. Runway Visual Range (RVR)− An instrumen-

tally derived value, based on standard calibrations,

that represents the horizontal distance a pilot will see

down the runway from the approach end. It is based

on the sighting of either high intensity runway lights

or on the visual contrast of other targets whichever

yields the greater visual range. RVR, in contrast to

prevailing or runway visibility, is based on what a

pilot in a moving aircraft should see looking down the

runway. RVR is horizontal visual range, not slant

visual range. It is based on the measurement of a

transmissometer made near the touchdown point of

the instrument runway and is reported in hundreds of

feet. RVR is used in lieu of RVV and/or prevailing

visibility in determining minimums for a particular

runway.

1. Touchdown RVR

− The RVR visibility

readout values obtained from RVR equipment

serving the runway touchdown zone.

2. Mid-RVR

− The RVR readout values obtained

from RVR equipment located midfield of the runway.

Pilot/Controller Glossary

10/12/17

PCG V−3

3. Rollout RVR− The RVR readout values

obtained from RVR equipment located nearest the

rollout end of the runway.

(See ICAO term FLIGHT VISIBILITY.)

(See ICAO term GROUND VISIBILITY.)

(See ICAO term RUNWAY VISUAL RANGE.)

(See ICAO term VISIBILITY.)

VISIBILITY [ICAO]− The ability, as determined by

atmospheric conditions and expressed in units of

distance, to see and identify prominent unlighted

objects by day and prominent lighted objects by

night.

a. Flight Visibility−The visibility forward from

the cockpit of an aircraft in flight.

b. Ground Visibility−The visibility at an aero-

drome as reported by an accredited observer.

c. Runway Visual Range [RVR]−The range over

which the pilot of an aircraft on the centerline of a

runway can see the runway surface markings or the

lights delineating the runway or identifying its

centerline.

VISUAL APPROACH− An approach conducted on

an instrument flight rules (IFR) flight plan which

authorizes the pilot to proceed visually and clear of

clouds to the airport. The pilot must, at all times, have

either the airport or the preceding aircraft in sight.

This approach must be authorized and under the

control of the appropriate air traffic control facility.

Reported weather at the airport must be ceiling at or

above 1,000 feet and visibility of 3 miles or greater.

(See ICAO term VISUAL APPROACH.)

VISUAL APPROACH [ICAO]− An approach by an

IFR flight when either part or all of an instrument

approach procedure is not completed and the

approach is executed in visual reference to terrain.

VISUAL APPROACH SLOPE INDICATOR−

(See AIRPORT LIGHTING.)

VISUAL CLIMB OVER AIRPORT (VCOA)− A

departure option for an IFR aircraft, operating in

visual meteorological conditions equal to or greater

than the specified visibility and ceiling, to visually

conduct climbing turns over the airport to the

published “climb−to” altitude from which to proceed

with the instrument portion of the departure. VCOA

procedures are developed to avoid obstacles greater

than 3 statute miles from the departure end of the

runway as an alternative to complying with climb

gradients greater than 200 feet per nautical mile.

Pilots are responsible to advise ATC as early as

possible of the intent to fly the VCOA option prior to

departure. These textual procedures are published in

the ‘Take−Off Minimums and (Obstacle) Departure

Procedures’ section of the Terminal Procedures

Publications and/or appear as an option on a Graphic

ODP.

(See AIM.)

VISUAL DESCENT POINT− A defined point on the

final approach course of a nonprecision straight-in

approach procedure from which normal descent from

the MDA to the runway touchdown point may be

commenced, provided the approach threshold of that

runway, or approach lights, or other markings

identifiable with the approach end of that runway are

clearly visible to the pilot.

VISUAL FLIGHT RULES− Rules that govern the

procedures for conducting flight under visual

conditions. The term “VFR” is also used in the

United States to indicate weather conditions that are

equal to or greater than minimum VFR requirements.

In addition, it is used by pilots and controllers to

indicate type of flight plan.

(See INSTRUMENT FLIGHT RULES.)

(See INSTRUMENT METEOROLOGICAL

CONDITIONS.)

(See VISUAL METEOROLOGICAL

CONDITIONS.)

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

VISUAL HOLDING− The holding of aircraft at

selected, prominent geographical fixes which can be

easily recognized from the air.

(See HOLDING FIX.)

VISUAL METEOROLOGICAL CONDITIONS−

Meteorological conditions expressed in terms of

visibility, distance from cloud, and ceiling equal to or

better than specified minima.

(See INSTRUMENT FLIGHT RULES.)

(See INSTRUMENT METEOROLOGICAL

CONDITIONS.)

(See VISUAL FLIGHT RULES.)

VISUAL SEGMENT−

(See PUBLISHED INSTRUMENT APPROACH

PROCEDURE VISUAL SEGMENT.)

Pilot/Controller Glossary 10/12/17

PCG V−4

VISUAL SEPARATION− A means employed by

ATC to separate aircraft in terminal areas and en route

airspace in the NAS. There are two ways to effect this

separation:

a. The tower controller sees the aircraft involved

and issues instructions, as necessary, to ensure that

the aircraft avoid each other.

b. A pilot sees the other aircraft involved and upon

instructions from the controller provides his/her own

separation by maneuvering his/her aircraft as

necessary to avoid it. This may involve following

another aircraft or keeping it in sight until it is no

longer a factor.

(See SEE AND AVOID.)

(Refer to 14 CFR Part 91.)

VLF−

(See VERY LOW FREQUENCY.)

VMC−

(See VISUAL METEOROLOGICAL

CONDITIONS.)

VOICE SWITCHING AND CONTROL SYSTEM−

The VSCS is a computer controlled switching system

that provides air traffic controllers with all voice

circuits (air to ground and ground to ground)

necessary for air traffic control.

(See VOICE SWITCHING AND CONTROL

SYSTEM.)

(Refer to AIM.)

VOR− A ground-based electronic navigation aid

transmitting very high frequency navigation signals,

360 degrees in azimuth, oriented from magnetic

north. Used as the basis for navigation in the National

Airspace System. The VOR periodically identifies

itself by Morse Code and may have an additional

voice identification feature. Voice features may be

used by ATC or FSS for transmitting instructions/

information to pilots.

(See NAVIGATIONAL AID.)

(Refer to AIM.)

VOR TEST SIGNAL−

(See VOT.)

VORTAC− A navigation aid providing VOR

azimuth, TACAN azimuth, and TACAN distance

measuring equipment (DME) at one site.

(See DISTANCE MEASURING EQUIPMENT.)

(See NAVIGATIONAL AID.)

(See TACAN.)

(See VOR.)

(Refer to AIM.)

VORTICES− Circular patterns of air created by the

movement of an airfoil through the air when

generating lift. As an airfoil moves through the

atmosphere in sustained flight, an area of area of low

pressure is created above it. The air flowing from the

high pressure area to the low pressure area around and

about the tips of the airfoil tends to roll up into two

rapidly rotating vortices, cylindrical in shape. These

vortices are the most predominant parts of aircraft

wake turbulence and their rotational force is

dependent upon the wing loading, gross weight, and

speed of the generating aircraft. The vortices from

medium to super aircraft can be of extremely high

velocity and hazardous to smaller aircraft.

(See AIRCRAFT CLASSES.)

(See WAKE TURBULENCE.)

(Refer to AIM.)

VOT− A ground facility which emits a test signal to

check VOR receiver accuracy. Some VOTs are

available to the user while airborne, and others are

limited to ground use only.

(See CHART SUPPLEMENT U.S.)

(Refer to 14 CFR Part 91.)

(Refer to AIM.)

VR−

(See VFR MILITARY TRAINING ROUTES.)

VSCS−

(See VOICE SWITCHING AND CONTROL

SYSTEM.)

VTA−

(See VERTEX TIME OF ARRIVAL.)

VTOL AIRCRAFT−

(See VERTICAL TAKEOFF AND LANDING

AIRCRAFT.)

Pilot/Controller Glossary

10/12/17

PCG W−1

WA−

(See AIRMET.)

(See WEATHER ADVISORY.)

WAAS−

(See WIDE-AREA AUGMENTATION SYSTEM.)

WAKE TURBULENCE− Phenomena resulting from

the passage of an aircraft through the atmosphere.

The term includes vortices, thrust stream turbulence,

jet blast, jet wash, propeller wash, and rotor wash

both on the ground and in the air.

(See AIRCRAFT CLASSES.)

(See JET BLAST.)

(See VORTICES.)

(Refer to AIM.)

WARNING AREA−

(See SPECIAL USE AIRSPACE.)

WAYPOINT− A predetermined geographical posi-

tion used for route/instrument approach definition,

progress reports, published VFR routes, visual

reporting points or points for transitioning and/or

circumnavigating controlled and/or special use

airspace, that is defined relative to a VORTAC station

or in terms of latitude/longitude coordinates.

WEATHER ADVISORY− In aviation weather

forecast practice, an expression of hazardous weather

conditions not predicted in the area forecast, as they

affect the operation of air traffic and as prepared by

the NWS.

(See AIRMET.)

(See SIGMET.)

WEATHER RECONNAISSANCE AREA (WRA)−

A WRS is airspace with defined dimensions and

published by Notice to Airmen, which is established

to support weather reconnaissance/research flights.

Air traffic control services are not provided within

WRAs. Only participating weather reconnaissance/

research aircraft from the 53

Weather

Reconnaissance Squadron and National Oceanic and

Atmospheric Administration Aircraft Operations

Center are permitted to operate within a WRA. A

WRA may only be established in airspace within U.S.

Flight Information Regions outside of U.S. territorial

airspace.

WHEN ABLE−

a. In conjunction with ATC instructions, gives the

pilot the latitude to delay compliance until a

condition or event has been reconciled. Unlike “pilot

discretion,” when instructions are prefaced “when

able,” the pilot is expected to seek the first

opportunity to comply.

b. In conjunction with a weather deviation

clearance, requires the pilot to determine when he/she

is clear of weather, then execute ATC instructions.

c. Once a maneuver has been initiated, the pilot is

expected to continue until the specifications of the

instructions have been met. “When able,” should not

be used when expeditious compliance is required.

WIDE-AREA AUGMENTATION SYSTEM

(WAAS)− The WAAS is a satellite navigation system

consisting of the equipment and software which

augments the GPS Standard Positioning Service

(SPS). The WAAS provides enhanced integrity,

accuracy, availability, and continuity over and above

GPS SPS. The differential correction function

provides improved accuracy required for precision

approach.

WIDE AREA MULTILATERATION (WAM)– A

distributed surveillance technology which may

utilize any combination of signals from Air Traffic

Control Radar Beacon System (ATCRBS) (Modes A

and C) and Mode S transponders, and ADS-B

transmissions. Multiple geographically dispersed

ground sensors measure the time-of-arrival of the

transponder messages. Aircraft position is deter-

mined by joint processing of the

time-difference-of-arrival (TDOA) measurements

computed between a reference and the ground

stations’ measured time-of-arrival.

WILCO− I have received your message, understand

it, and will comply with it.

WIND GRID DISPLAY− A display that presents the

latest forecasted wind data overlaid on a map of the

ARTCC area. Wind data is automatically entered and

updated periodically by transmissions from the

National Weather Service. Winds at specific

altitudes, along with temperatures and air pressure

can be viewed.

Pilot/Controller Glossary 10/12/17

PCG W−2

WIND SHEAR− A change in wind speed and/or wind

direction in a short distance resulting in a tearing or

shearing effect. It can exist in a horizontal or vertical

direction and occasionally in both.

WIND SHEAR ESCAPE– An unplanned abortive

maneuver initiated by the pilot in command (PIC) as

a result of onboard cockpit systems. Wind shear

escapes are characterized by maximum thrust climbs

in the low altitude terminal environment until wind

shear conditions are no longer detected.

WING TIP VORTICES−

(See VORTICES.)

WORDS TWICE−

a. As a request: “Communication is difficult.

Please say every phrase twice.”

b. As information: “Since communications are

difficult, every phrase in this message will be spoken

twice.”

WS−

(See SIGMET.)

(See WEATHER ADVISORY.)

WST−

(See CONVECTIVE SIGMET.)

(See WEATHER ADVISORY.)