ACCELERATE – STOP DISTANCE AVAILABLE (ASDA). See declared distances.
AIR CARRIER. An operator, which: (1) performs at least five round trips per week between two or more points and publishes flight schedules which specifies the times, days of the week, and places between which such flights are performed; or (2) transport mail by air pursuant to a current contract with the U.S. Postal Service. Certified in accordance with Federal Aviation Regulation (FAR) Parts 121 and 127.
AIR ROUTE TRAFFIC CONTROL CENTER (ARTCC). A facility established to provide air traffic control service to an aircraft operating on an IFR flight plan within controlled airspace and principally during the enroute phase of flight.
AIR TAXI. An air carrier certificated in accordance with FAR Part 135 and authorized to provide, on demand, public transportation of persons and property by aircraft. Generally operates small aircraft for hire for specific trips.
AIRCRAFT. An aircraft is a device that is used or intended to be used for flight in the air.
AIRCRAFT APPROACH CATEGORY. A grouping of aircraft based on 1.3 times the stall speed in their maximum certificated landing weight. The categories are as follows:
. Category A: Speed less than 91 knots.

. Category B: Speed 91 knots or more, but less than 121 knots.

. Category C: Speed 121 knots or more, but less than 141 knots.

. Category D: Speed 141 knots or more, but less that 166 knots.

. Category E: Speed greater than 166 knots.

AIRPLANE. Means an engine-driven fixed-wing aircraft heavier than air that is supported in flight by the dynamic reaction of the air against its wings.
AIRPLANE DESIGN GROUP (ADG). A grouping of aircraft based upon relative wingspan or tail height (whichever is most demanding). The groups are as follows:
Group Tail Height (ft) Wingspan (ft)
1 <20 <49
II 20-<30 49-<79
III 30-<45 79-<118