°  Degree
°C  Degree Celsius
°F  Degree Fahrenheit
 Liter
A  Ampere
A/C  Aircraft
A/I  Anti-Ice
ABM  Auto Brake Control Module
ABV  Auxiliary Power-Unit Bleed-Valve
AC  Advisory Circular
ACARS  Aircraft Communication Addressing and Reporting System
ACE  Actuator Control Electronics
ACMP  Alternating-Current Motor-Driven Pump
ACN  Aircraft Classification Number
ACP  Audio Control Panel
ACT  Automatic Tilt
ADA  Air Data Application
ADC  Air Data Computer
ADF  Automatic Direction Finder
ADI  Attitude Director Indicator
ADS  Air Data System
ADSP  Air Data Smart Probe
AFCS  Automatic-Flight Control System
AFCU  Auxiliary Fuel Conditioning Unit
AFE  Above Field Elevation
AFM  Airplane Flight Manual