°C -- Degrees Celsius (or Centigrade)
°F -- Degrees Fahrenheit
A/P -- Autopilot
A/T -- Autothrottle
AC -- Alternating Current
ACCUM -- Accumulator
ACFT -- Aircraft
ACM -- Air Cycle Machine
ADF -- Automatic Direction Finder
ADI -- Attitude Display Indicator
AFCS -- Automatic Flight Control System
AFGCS -- Automatic Flight Guidance & Control
AFM -- Airplane Flight Manual
AGL -- Above Ground Level
AIL -- Aileron
ALRT -- Alert
ALT -- Alternate/Altitude
AMP(S) -- Ampere(s)
ANNUN -- Annunciator
AOA -- Angle of Attack
AP -- Autopilot
APP -- Approach
APU -- Auxiliary Power Unit
ARINC -- Aeronautical Radio Incorporated
ASCB -- Avionics Standard Communication Bus
ATC -- Air Traffic Control
ATIS -- Automatic Terminal Information Service
ATT-REF -- Attitude-Reference
AUTO -- Automatic
AUX -- Auxiliary
BATT -- Battery