Aeronautical Terms beginning with A
A/FD
Airport/Facility Directory—obsolete. Changed to Chart Supplement.
AAS
Airport Advisory Service
AAWU
Alaskan Aviation Weather Unit
AC
Advisory Circular
ACAR
Aircraft Communications Addressing and Reporting System
ADCUS
Advise Customs
ADDS
Aviation Digital Data Service
ADF
Automatic Direction Finder
ADIZ
Air Defense Identification Zone
Administrator
The Federal Aviation Administrator or any person to whom he has delegated his authority in the matter concerned.
ADS-B
Automatic Dependent Surveillance-Broadcast
Aerodynamic coefficients
Non-dimensional coefficients for aerodynamic forces and moments.
AFB
Air Force Base
AFCS
Automatic Flight Control System
AFIS
Automatic Flight Information Service
AFM
Airplane Flight Manual.
AGL
Above Ground Level.
Air carrier
A person who undertakes directly by lease, or other arrangement, to engage in air transportation.
Air commerce
Interstate, overseas, or foreign air commerce or the transportation of mail by aircraft or any operation or navigation of aircraft within the limits of any Federal airway or any operation or navigation of aircraft which directly affects, or which may endanger safety in, interstate, overseas, or foreign air commerce.
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.
Air traffic control
A service operated by appropriate authority to promote the safe, orderly, and expeditious flow of air traffic.
Air Traffic Service (ATS) route
A specified route designated for channeling the flow of traffic as necessary for the provision of air traffic services. The term “ATS route” refers to a variety of airways, including jet routes, area navigation (RNAV) routes, and arrival and departure routes. An ATS route is defined by route specifications, which may include:
(1) An ATS route designator;
(2) The path to or from significant points;
(3) Distance between significant points;
(4) Reporting requirements; and
(5) The lowest safe altitude determined by the appropriate authority.
Air transportation
Interstate, overseas, or foreign air transportation or the transportation of mail by aircraft.
Aircraft
A device that is used or intended to be used for flight in the air.
Aircraft engine
An engine that is used or intended to be used for propelling aircraft. It includes turbosuperchargers, appurtenances, and accessories necessary for its functioning, but does not include propellers.
Airframe
The fuselage, booms, nacelles, cowlings, fairings, airfoil surfaces (including rotors but excluding propellers and rotating airfoils of engines), and landing gear of an aircraft and their accessories and controls.
Airplane
An engine-driven fixed-wing aircraft heavier than air, that is supported in flight by the dynamic reaction of the air against its wings.
Airport
An area of 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.
Airship
An engine-driven lighter-than-air aircraft that can be steered.
Alert Area
An alert area is established to inform pilots of a specific area wherein a high volume of pilot training or an unusual type of aeronautical activity is conducted.
ALS
Approach Light System.
Alternate airport
An airport at which an aircraft may land if a landing at the intended airport becomes inadvisable.
Altitude engine
A reciprocating aircraft engine having a rated takeoff power that is producible from sea level to an established higher altitude.
Amateur rocket
An unmanned rocket that:
(1) Is propelled by a motor or motors having a combined total impulse of 889,600 Newton-seconds (200,000 pound-seconds) or less; and
(2) Cannot reach an altitude greater than 150 kilometers (93.2 statute miles) above the earth’s surface.
Appliance
Any instrument, mechanism, equipment, part, apparatus, appurtenance, or accessory, including communications equipment, that is used or intended to be used in operating or controlling an aircraft in flight, is installed in or attached to the aircraft, and is not part of an airframe, engine, or propeller.
Approved
Unless used with reference to another person, approved by the FAA or any person to whom the FAA has delegated its authority in the matter concerned, or approved under the provisions of a bilateral agreement between the United States and a foreign country or jurisdiction.
APU
Auxiliary Power Unit.
Area navigation (RNAV)
A method of navigation that permits aircraft operations on any desired flight path.
Area navigation (RNAV) route
An ATS route based on RNAV that can be used by suitably equipped aircraft.
Armed Forces
The Army, Navy, Air Force, Marine Corps, and Coast Guard, including their regular and reserve components and members serving without component status.
ASR
Airport Surveillance Radar.
ATC
Air Traffic Control.
ATS
Air Traffic Service.
Autorotation
A rotorcraft flight condition in which the lifting rotor is driven entirely by action of the air when the rotorcraft is in motion.
Auxiliary rotor
A rotor that serves either to counteract the effect of the main rotor torque on a rotorcraft or to maneuver the rotorcraft about one or more of its three principal axes.
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