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A.I.R. - Acronym for Airport Information Reference exclusive to flyingdatabase.com.

ABSOLUTE ALTITUDE - The height of an aircraft above actual measurable terrain.

ABSOLUTE CEILING - Maximum altitude above sea level (MSL) at which an aircraft can maintain level flight under standard flight conditions.

ACCELERATED STALL - Any stall made to occur at other than 1G load.

ACCELEROMETER - An inertial device for measuring acceleration, usually in three orthogonal axes (lateral X, longitudinal Y, and vertical Z).

ACCIDENT - Occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight.

ADF - Automatic Direction Finder that determines relative bearing to a transmitter to which it is tuned, in either the UHF band or VHF band.

ADIABATIC LAPSE RATE - The rate at which ascending air and descending air warms, given no heat is added or taken away.

ADVERSE YAW - Yaw generated when the ailerons are used. The lifting wing generates more drag, causing the aircraft to yaw towards it.

ADMINISTRATOR - means the Federal Aviation Administrator or any person to whom he has delegated his authority in the matter concerned.

AERODYNAMIC COEFFICIENTS - Non-dimensional coefficients for aerodynamic forces and moments.

AFM - Airplane Flight Manual.

AGL - Above Ground Level, as a measurement of altitude above specific terrain.

AILERON - The movable areas of a wing form that control or affect the roll of an aircraft by working opposite one another (eg. up-aileron on the right wing and down-aileron on the left).

AIRCRAFT - Device that is used or intended to be used for flight in the air.

AIR CARRIER - 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 - Service operated by appropriate authority to promote the safe, orderly, and expeditious flow of air traffic.

AIR TRAFFIC SERVICE ROUTE - 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: an ATS route designator; the path to or from significant points; distance between significant points; reporting requirements; and 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 ENGINE - An engine that is used or intended to be used for propelling aircraft. It includes turbo superchargers, 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.

AIRFOIL - The shape of any flying surface, principally a wing, as seen in a side-view or cross section.

AIRSPEED INDICATOR - An instrument or device that measures the airspeed of an aircraft through an air mass.

AIR TAXI - An aircraft operator who conducts operations for hire or compensation in accordance with FAR Part 135 in an aircraft with 30 or fewer passenger seats.

ALERT AREA - 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.

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.

ALTIMETER - An adjustable aneroid-barometric cockpit instrument used to measure an aircrafts altitude.

AME - Aviation Medical Examiner.

AMPHIBIAN - A seaplane or floatplane with retractable wheels for use on land as well as water.

ANGLE OF ATTACK - The angle between the chord line of the wing of an aircraft and the relative wind.

ANGLE OF INCIDENCE - The angle at which an airfoil in normally fixed in relation to the longitudinal axis of the aircraft.

ANHEDRAL - The downward angel of a wing in relation to a horizontal cross-section line.

AOPA - Aircraft Owners and Pilots Association.

APPROVED - Unless used with reference to another person, means approved by the Administrator.

APRON - The hard-surface or paved area around a hangar.

ARTIFICIAL HORIZON - A vacuum-powered panel instrument that displays pitch and roll movements about the lateral and longitudinal axis (eg. Attitude Indicator).

APU - Auxiliary power unit.

ASPECT RATIO - The ratio of the span to the chord of an airfoil (eg. a high-aspect ratio wing has wide span and narrow chord and a low-aspect ratio wing has narrow span and a wide chord).

ATIS - Automatic Terminal Information Service.

ATTITUDE INDICATOR - A vacuum powered instrument which displays pitch and roll movement about the lateral and longitudinal axes.

AUTOGYRO - An aircraft, often wingless, with unpowered rotary airfoil blades that auto-rotate and serve as wings as it moves through the air when driven by an engine.

AUTO-ROTATION - Automatic rotation of rotary blades from a helicopter in an unpowered glide or forward movement of an autogyro.

AUTOMATIC TERMINAL INFORMATION SERVICE (ATIS) - Continuous broadcast of recorded non-control information in selected terminal areas, to improve controller effectiveness and to relieve frequency congestion by automating repetitive transmissions of essential but routine information.

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.

AVGAS - Aviation Gasoline (piston aircraft fuel).

AXIS - The line around which a body rotates.