Aeronautical Terms beginning with A
A/FD
Airport/Facility Directory—obsolete. Changed to Chart Supplement.
AAI
Arrival Aircraft Interval
AAR
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.
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]
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
Air Carrier District Office
Acknowledge
Let me know that you have received my message.
Acknowledge [ICAO]
Let me know that you have received and understood this message.
ACL
Aircraft List
ACLS
Automatic Carrier Landing System
ACLT
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. (Refer to 14 CFR Part 91.
Acrobatic Flight [ICAO]
Maneuvers intentionally performed by an aircraft involving an abrupt change in its attitude, an abnormal attitude, or an abnormal variation in speed.
ACS
Airman Certification Standards
Active Runway
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)
A measure of the current estimated navigational performance. Also referred to as Estimated Position Error (EPE).
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. e. Weather and chaff information. f. Weather assistance. g. Bird activity information. h. Holding pattern surveillance. Additional services 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.
ADF
Automatic Direction Finder
ADI
Air Defense Identification Zone
ADLY
Arrival Delay
Administrator
The Federal Aviation Administrator or any person to whom he/she has delegated his/her authority in the matter concerned.
ADR
Airport Departure Rate
ADS [ICAO]
ICAO Term Automatic Dependent Surveillance
ADS-B
Automatic Dependent Surveillance-Broadcast
ADS-C
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.
Advisory Frequency
The appropriate frequency to be used for Airport Advisory Service.
Advisory Service
Advice and information provided by a facility to assist pilots in the safe conduct of flight and aircraft movement.
Aerial Refueling
A procedure used by the military to transfer fuel from one aircraft to another during flight.
Aerodrome
A defined area on land or water (including any buildings, installations and equipment) 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 elevation 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.
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: Sectional Aeronautical Charts, VFR Terminal Area Charts, World Aeronautical Charts (WAC), En Route Low Altitude Charts, En Route High Altitude Charts, Instrument Approach Procedures (IAP) Charts, Instrument Departure Procedure (DP) Charts, Standard Terminal Arrival (STAR) Charts.
Aeronautical Chart [ICAO]
A representation 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 instructional information concerning health, medical facts, factors affecting flight safety, accident and hazard reporting, and types of aeronautical charts and their use.
Aeronautical Information Publication (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.
Affirmative
Yes.
AFP
Airspace Flow Program
AGL Altitude
Altitude expressed in feet measured above ground level.
AIM
Aeronautical Information Manual
AIP [ICAO]
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 emergency condition declared by a designated authority. This condition exists when an attack upon the continental U.S., Alaska, Canada, or U.S. installations in Greenland by hostile aircraft or missiles is considered probable, is imminent, or is taking place.
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.
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 communication, 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.
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/assistance services may be provided to VFR aircraft.
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.
Air Traffic
Aircraft operating in the air or on an airport surface, exclusive of loading ramps and parking areas.
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.
Air Traffic Control
A service operated by appropriate authority to promote the safe, orderly and expeditious flow of air traffic.
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 clearance relates.
Air Traffic Control Service
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.
Air Traffic Control System Command Center
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. 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. c. U.S. Notice to Airmen (NOTAM) Office. Responsible for collecting, maintaining, and distributing NOTAMs for the U.S. civilian and military, as well as international aviation communities. 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 meteorologists 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.
Air Traffic [ICAO]
All aircraft in flight or operating on the maneuvering area of an aerodrome.
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.
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 A-E.
Aircraft Classes
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.
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.
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.”
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.
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.
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.
Airman Certification Standards (ACS)
An FAA published list of standards which must be met for the issuance of a particular pilot certificate or rating. FAA inspectors and designated pilot examiners use these standards when conducting pilot practical tests and flight instructors should use the ACS while preparing applicants for practical tests.
Airmen’s Meteorological Information
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.
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.
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.
Airport Lighting
Various lighting aids that may be installed on an airport.
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.
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.
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 designed 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
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.
Airport Traffic Control Tower
Tower.
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. (Renamed to Chart Supplement)
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: Indicated Airspeed, True 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.
Airway Beacon
Used to mark airway segments in remote mountain areas. The light flashes Morse Code to identify the beacon site.
Airway [ICAO]
A control area or portion thereof established in the form of corridor equipped with radio navigational aids.
AIT
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
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 transiting the area are equally responsible for collision avoidance.
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
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 numerals used to show identification, altitude, beacon code, and other information concerning a target on a radar display.
ALSF-1
Approach Light System With Sequenced Flashing Lights In ILS CAT-I Configuration
ALSF-2
Approach Light System With Sequenced Flashing Lights In ILS Cat-II Configuration. The ALSF-2 May Operate As An SSALR When Weather Conditions Permit
Alternate Aerodrome [ICAO]
An aerodrome 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.
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).
Altitude
The height of a level, point, or object measured in feet Above Ground Level (AGL) or 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.
Altitude Reservation
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.
Altitude Restriction
An altitude or altitudes, 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 restrictions is no longer required during a climb or descent.
Altitude [ICAO]
The vertical distance of a level, a point or an object considered as a point, measured from mean sea level (MSL).
ALTRV
Altitude Reservation
AMVER
Automated Mutual-Assistance Vessel Rescue System
APB
Automated Problem Detection Boundary
APD
Automated Problem Detection
APDIA
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.
Approach Control Facility
A terminal ATC facility that provides approach control service in a terminal area.
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.
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 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: ALSF-1, ALSF-2, SSALF, SSALR, MALSF, MALSR, LDIN, RAIL, ODALS.
Approach Sequence
The order in which aircraft are positioned while on approach or awaiting approach clearance.
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.
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: Minimum En Route IFR Altitude, Minimum IFR Altitude, Minimum Obstruction Clearance Altitude, Minimum Vectoring Altitude.
Appropriate Terrain Clearance Minimum Altitude
Any of the following: Minimum En Route IFR Altitude, Minimum IFR Altitude, Minimum Obstruction Clearance Altitude, 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.
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 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
Includes Standard T, Modified T, Standard I, Terminal Arrival Area (TAA).
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
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.
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 jurisdiction 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 automated program designed to assist in sequencing aircraft destined for the same airport.
Arrival Time
The time an aircraft touches down on arrival.
ARSR
Air Route Surveillance Radar
ARTCC
Air Route Traffic Control Center
ARTS
Automated Radar Terminal Systems
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 upgrades the existing ARTS III system by providing improved tracking, continuous data recording, and fail-soft capabilities.
ASDA
Accelerate-Stop Distance Available
ASDA [ICAO]
ICAO Term Accelerate-Stop Distance Available
ASDE
Airport Surface Detection Equipment
ASF
Airport Stream Filter
ASLAR
Aircraft Surge Launch And Recovery
ASP
Arrival Sequencing Program
ASR
Airport Surveillance Radar
ASR APPROACH
Surveillance Approach
Associated
A radar target displaying a data block with flight identification and altitude information.
ATC
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.
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.
ATC Clearance
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.”
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.
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 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.
ATCAA
ATC Assigned Airspace
ATCRBS
Radar
ATCSCC
Air Traffic Control System Command Center
ATCT
Tower
ATD
Along-Track Distance
ATIS
Automatic Terminal Information Service
ATIS [ICAO]
ICAO Term Automatic Terminal Information Service
ATS Route [ICAO]
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 variously, 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 conditions are less than approximately 4,000 RVR.
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.
Automated Problem Detection (APD)
An Automation Processing capability that compares trajectories in order to predict conflicts.
Automated Problem Detection Boundary (ABP)
The adapted distance beyond a facilities boundary defining the airspace within which URET performs conflict detection.
Automated Problem Detection Inhibited 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.
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.
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 Observing System (ASOS), Automated Weather Sensor System (AWSS) and Automated Weather Observation System (AWOS).
Automatic Altitude Report
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.
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 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.
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/AWSS/AWOS 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.”
Automatic Terminal Information Service [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.
Autorotative Landing/Touchdown Autorotation
Used by a pilot to indicate that the landing will be made without applying power to the rotor.
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.
AWW
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.
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