PilotController Glossary
<P>PilotController Glossary</P><P>**** Hidden Message *****</P> Pilot/Controller Glossary 7/31/08
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 “.” 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
a. Terms Added:
AUTOMATIC FLIGHT INFORMATION SERVICE (AFIS) - ALASKA FSS ONLY
b. Editorial/format changes were made where necessary. Revision bars were not used due to the insignificant
nature of the changes.
Pilot/Controller Glossary 2/14/08
PCG A-1
A
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 term inate a preplanned aircraft
maneuver; e.g., an aborted takeoff.
ACC -
(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
- 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 my message.
(See ICAO term ACKNOWLEDGE.)
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 - 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.
Pilot/Controller Glossary 2/14/08
PCG A-2
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.
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 -
(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 EN ROUTE FLIGHT ADVISORY
SERVICE.)
(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 - Aeronautical
beacon used to indicate the location of an aerodrome
from the air.
AERODROME CONTROL SERVICE - Air
traffic control service for aerodrome traffic.
AERODROME CONTROL TOWER - A
unit established to provide air traffic control service
to aerodrome traffic.
AERODROME ELEVATION - The eleva‐
tion of the highest point of the landing area.
AERODROME TRAFFIC CIRCUIT - 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
Pilot/Controller Glossary 2/14/08
PCG A-3
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,
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. World Aeronautical Charts (WAC)
(1:1,000,000)- Provide a standard series of aeronau‐
tical charts covering land areas of the world at a size
and scale convenient for navigation by moderate
speed aircraft. Topographic information includes
cities and towns, principal roads, railroads, distinc‐
tive landmarks, drainage, and relief. Aeronautical
inform ation includes visual and radio aids to
navigation, airports, airways, restricted areas,
obstructions, and other pertinent data.
d. En Route Low Altitude Charts- Provide
aeronautical information for en route instrument
navigation (IF R) 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.
e. 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.
f. Instrument Approach Procedures (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/MLS, and RNAV. These charts are identified by
the type of navigational aid(s) which provide final
approach guidance.
g. 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.
h. 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.
i. 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 - 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) - A publication issued by or with
2/14/08
PCG A-4
the authority of a State and containing aeronautical
information of a lasting character essential to air
navigation.
A/FD(See AIRPORT/FACILITY DIRECTORY.)
AFFIRMATIVE- Yes.
AFIS(See AUTOMATIC FLIGHT INFORMATION
SERVICE - ALASKA FSSs ONLY.)
AFP(See AIRSPACE FLOW PROGRAM.)
AIM(See AERONAUTICAL INFORMATION
MANUAL.)
AIP -
(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 speci‐
fied 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- 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/as‐
sistance 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.)
Pilot/Controller Glossary 7/31/08
Pilot/Controller Glossary 2/14/08
PCG A-5
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 - 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
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 -
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 - 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).
Responsible for approving IFR flights at designated
high density traffic airports (John F. Kennedy,
LaGuardia, and Ronald Reagan Washington
National) during specified hours.
(Refer to 14 CFR Part 93.)
(Refer to AIRPORT/FACILITY DIRECTORY.)
7/31/08 Pilot/Controller Glossary
2/14/08
PCG A-6
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
“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 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 - 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
CategoryB 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 Heavy, Large, and Small as follows:
a. Heavy- Aircraft capable of takeoff weights of
more than 255,000 pounds whether or not they are
operating at this weight during a particular phase of
flight.
b. Large- Aircraft of more than 41,000 pounds,
maximum certificated takeoff weight, up to 255,000
pounds.
c. Small- Aircraft of 41,000 pounds or less
maximum certificated takeoff weight.
(Refer to AIM.)
AIRCRAFT CONFLICT- Predicted conflict, within
URET, 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 USER REQUEST EVALUATION TOOL.)
AIRCRAFT LIST (ACL)- A view available with
URET 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 USER REQUEST EVALUATION 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:
Pilot/Controller Glossary 7/31/08
Pilot/Controller Glossary 2/14/08
PCG A-7
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.
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/FACILITY DIRECTORY- 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.
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 beam s 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.
7/31/08 Pilot/Controller Glossary
2/14/08
PCG A-8
6. MALSR- Medium Intensity Approach Light
System with Runway Alignment Indicator Lights.
7. LDIN- 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
edge when installed on a runway equipped with a
VASI.
(Refer to FAAO 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.)
AIR PORT REFERENCE POINT (ARP)- The
approximate geometric center of all usable runway
surfaces.
AIRPORT RESERVATION OFFICE- Office re‐
sponsible for monitoring the operation of the high
density rule. Receives and processes requests for
IFR-operations at high density traffic 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
Pilot/Controller Glossary 7/31/08
Pilot/Controller Glossary 2/14/08
PCG A-9
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 a X-band Surface
Movement Radar and multilateration. Data from
these two sources are fused and presented on a digital
display.
c. ASDE-3X- an ASDE-X system that uses the
ASDE-3 Surface Movement Radar.
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 - 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.)
7/31/08 Pilot/Controller Glossary
2/14/08
PCG A-10
ALERFA (Alert Phase) - 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- A request originated by a flight
service station (FSS) or an air route traffic control
center (ARTCC) for an extensive communication
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 distance
measured from a point‐in‐space by systems using
area navigation reference capabilities that are not
subject to slant range errors.
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 - 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 - 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- Airspace utilization
under prescribed conditions normally employed for
the mass movement of aircraft or other special user
requirem ents 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.)
Pilot/Controller Glossary 7/31/08
Pilot/Controller Glossary 2/14/08
PCG A-11
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.)
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 - 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 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 - 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.
APPROPRIATE ATS AUTHORITY - 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 AUTHORITYa. 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 - 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).
7/31/08 Pilot/Controller Glossary
2/14/08
PCG A-12
AREA CONTROL CENTER - An air traffic
control facility primarily responsible for ATC
services being provided IFR aircraft during the en
route phase of flight. The U.S. equivalent facility is
an air route traffic control center (ARTCC).
AREA NAVIGATION- Area Navigation (RNAV)
provides enhanced navigational capability to the
pilot. RNAV equipment can compute the airplane
position, actual track and ground speed and then
provide meaningful information relative to a route of
flight selected by the pilot. Typical equipment will
provide the pilot with distance, time, bearing and
crosstrack error relative to the selected “TO” or
“active” waypoint and the selected route. Several
distinctly different navigational systems with
different navigational performance characteristics
are capable of providing area navigational functions.
Present day RNAV includes INS, LORAN, VOR/
DME, and GPS systems. Modern multi‐sensor
systems can integrate one or more of the above
systems to provide a more accurate and reliable
navigational system. Due to the different levels of
performance, area navigational capabilities can
satisfy different levels of required navigational
performance (RNP). The major types of equipment
are:
a. VORTAC referenced or Course Line Computer
(CLC) systems, which account for the greatest
number of RNAV units in use. To function, the CLC
must be within the service range of a VORTAC.
b. OMEGA/VLF, although two separate systems,
can be considered as one operationally. A long‐range
navigation system based upon Very Low Frequency
radio signals transmitted from a total of 17 stations
worldwide.
c. Inertial (INS) systems, which are totally
self‐contained and require no information from
external references. They provide aircraft position
and navigation information in response to signals
resulting from inertial effects on components within
the system.
d. MLS Area Navigation (MLS/RNAV), which
provides area navigation with reference to an MLS
ground facility.
e. LORAN‐C is a long‐range radio navigation
system that uses ground waves transmitted at low
frequency to provide user position information at
ranges of up to 600 to 1,200 nautical miles at both en
route and approach altitudes. The usable signal
coverage areas are determined by the signal‐to‐noise
ratio, the envelope‐to‐cycle difference, and the
geometric relationship between the positions of the
user and the transmitting stations.
f. GPS is a space‐base radio positioning,
navigation, and time‐transfer system. The system
provides highly accurate position and velocity
information, and precise time, on a continuous global
basis, to an unlimited number of properly equipped
users. The system is unaffected by weather, and
provides a worldwide common grid reference
system.
(See ICAO term AREA NAVIGATION.)
AREA NAVIGATION - A method of
navigation which permits aircraft operation on any
desired flight path within the coverage of station‐
referenced navigation aids or within the limits of the
capability of self‐contained aids, or a combination of
these.
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
Pilot/Controller Glossary 7/31/08
Pilot/Controller Glossary 2/14/08
PCG A-13
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.
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.) 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 ADVIS ORY LIS T- 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 -
(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.)
7/31/08 Pilot/Controller Glossary
2/14/08
PCG A-14
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-
URET 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 USER REQUEST EVALUATION 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.
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 -
(See ICAO Term AUTOMATIC TERMINAL
INFORMATION SERVICE.)
ATS ROUTE - A specified route designed for
channelling the flow of traffic as necessary for the
provision of air traffic services.
Note:The term “ATS Route” is used to mean vari‐
ously, airway, advisory route, controlled or
uncontrolled route, arrival or departure, etc.
AUTOLAND APPROACH- An autoland approach
is a precision instrument approach to touchdown and,
in some cases, through the landing rollout. An
autoland approach is performed by the aircraft
autopilot which is receiving position information
and/or steering commands from onboard navigation
equipment.
Note:Autoland and coupled approaches are flown
in VFR and IFR. It is common for carriers to require
their crews to fly coupled approaches and autoland
approaches (if certified) when the weather condi‐
tions are less than approximately 4,000 RVR.
(See COUPLED APPROACH.)
AUTOMATED INFORMATION TRANSFER- 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
rescue incident, including their predicted positions
and their characteristics.
(See FAAO 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.
Pilot/Controller Glossary 7/31/08
Pilot/Controller Glossary 2/14/08
PCG A-15
AUTOMATED PROBLEM DETECTION
BOUNDARY (APB)- The adapted distance beyond
a facilities boundary defining the airspace within
which URET performs conflict detection.
(See USER REQUEST EVALUATION TOOL.)
AUTOMATED PROBLEM DETECTION IN‐
HIBITED 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,
programmable 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 up‐
grades 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.
c. Program mable Indicator Data Processor
(P IDP). The PIDP is a modification to the
AN/TPX-42 interrogator system currently installed
in fixed RAPCONs. The PIDP detects, tracks, and
predicts secondary radar aircraft targets. These are
displayed by means of computer-generated symbols
and alphanumeric characters depicting flight identifi‐
cation, aircraft altitude, ground speed, and flight plan
data. Although primary radar targets are not tracked,
they are displayed coincident with the secondary
radar targets as well as with the other symbols and
alphanumerics. The system has the capability of
interfacing with ARTCCs.
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 Airport/Facility Directory 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) - 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 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
7/31/08 Pilot/Controller Glossary
2/14/08
PCG A-16
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
SERVICE (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, breaking action,
airport NOTAMs, and other applicable information.
The information is continuously broadcast over a
discrete VHF radio frequency (usually the ASOS
frequency.)
AUTOMATIC TERMINAL INFORMATION
SERVICE- 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
SERVICE - 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 SERVIC E- 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 EN ROUTE FLIGHT ADVISORY
SERVICE.)
(See TRANSCRIBED WEATHER BROADCAST.)
(See WEATHER ADVISORY.)
(Refer to AIM.) AWW(See SEVERE WEATHER FORECAST
ALERTS.)
AZIMUTH (MLS)- A magnetic bearing extending
from an MLS navigation facility.
Note:Azimuth bearings are described as magnetic
and are referred to as “azimuth” in radio telephone
communications.
Pilot/Controller Glossary 7/31/08
Pilot/Controller Glossary 2/14/08
PCG B-1
B
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.
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 - 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.
BOUNDARY LIGHTS(See AIRPORT LIGHTING.)
BRAKING ACTION (GOOD, FAIR, POOR, OR
NIL)- A report of conditions on the airport
movement area providing a pilot with a degree/
quality of braking that he/she might expect. Braking
action is reported in terms of good, fair, poor, or nil.
(See RUNWAY CONDITION READING.)
BRAKING ACTION ADVISORIES- When tower
controllers have received runway braking action
reports which include the terms “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 latest 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 inform ation if not volunteered 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 close parallel
operations, a breakout is used to direct threatened
aircraft away from a deviating aircraft.
BROADCAST- Transmission of information for
which an acknowledgement is not expected.
(See ICAO term BROADCAST.)
BROADCAST - A transmission of informa‐
tion relating to air navigation that is not addressed to
a specific station or stations.
Pilot/Controller Glossary 2/14/08
PCG C-1
C
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 - 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 2/14/08
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)-
A 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.
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
associated with wind shear. CAT is often encountered
in the vicinity of the jet stream.
(See WIND SHEAR.)
(See JET STREAM.)
CLEAR OF THE RUNWAYa. Taxiing aircraft, which is approaching a
runway, is clear of the runway when all parts of the
Pilot/Controller Glossary 2/14/08
PCG C-3
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 - The point of 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 - 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.
(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
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.
Pilot/Controller Glossary 2/14/08
PCG C-4
CLOSE PARALLEL RUNWAYS- Two parallel
runways whose extended centerlines are separated by
less than 4,300 feet, having a Precision Runway
Monitoring (PRM) system that permits simultaneous
independent ILS approaches.
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.)
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
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.
OR
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.
(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 RESTRIC TIONS - An ATC
instruction that requires an aircraft being vectored
Pilot/Controller Glossary 2/14/08
PCG C-5
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.