A/C Air-Conditioning
A/G Air/Ground
A/ICE Anti-Ice
A/P Autopilot
A/S Airspeed
A/SKID Anti-Skid
ABS Absolute
AC Advisory Circular, Alternating Current
ACARS Aircraft Communications Addressing and Reporting System
ACCEL Acceleration, Accelerate(d), Accelerometers
ACM Air Cycle Machine
ACMP Alternating Current Motor Pump/Electric Hydraulic Pump
ACOU AC Outlet Units
ACT Active
ACU Air-Conditioning Unit
ADC Air Data Computer
ADDR Address
ADF Automatic Direction Finder
ADG Air Driven Generator
ADI Attitude Director Indicator
ADS Air Data System
AEI All Engines Inoperating
AEO All Engines Operating
AFCS Automatic Flight Control System
AFM Airplane Flight Manual
AGL Above Ground Level
AHC Attitude Heading Computer