Fix or point that is ninety degrees right or left of the aircraft's position

Navigation system that allows for operation on any desired course within an area serviced by ground based navigation signals, or self contained airborne system

Instrument that by measuring the pressure of the atmosphere displays altitude information

Barometric pressure reading used to adjust the altimeter

Area of an airport used for loading/unloading, servicing, refueling, and parking of aircraft

Airport and Airways Surveillance Radar

Area Control Centre (Canada)

Amplitude Modulation

Auxiliary Power Unit

Aircraft Radio Control of Aerodrome Lighting