APB-
(See AUTOMATED PROBLEM DETECTION
BOUNDARY.)

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 [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-
(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.)
Pilot/Controller Glossary
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.