Airline Operational Control AP
Autopilot
AP/FD
Autopilot/Flight Director
APPR
Approach
APPU
Asymmetry Position Pick Off Unit APU
Auxiliary Power Unit
ARINC
Aeronautical Radio Incorporated
ARPT
Airport
ASCII
American Standard Code for Information Interchange ASI
Airspeed Indicator
ASIC
Application Specific Integrated Circuits
ASM
Aircraft Schematics Manual
ASP
Audio Selector Panel
ASSY
Assembly
ATA
Air Transport Association of America ATC
Air Traffic Control ATE
Automatic Test Equipment
ATLAS
Abbreviated Test Language for All Systems ATS
Autothrottle System
ATSU
Air Traffic Service Unit ATT
Attitude
ATTND
Attendant
AUTO
Automatic
AUX
Auxiliary
AVAIL
Available
AVNCS
Avionics
AWM
Aircraft Wiring Manual
AWY
Airway AZ
Azimuth B Blue
BARO
Barometric BAT
Battery
BCD
Binary Coded Decimal BCL
Battery Charge Limiter BFO
Beat Frequency Oscillator
BGM
Boarding Music
BITE
Built-in Test Equipment
BMC
Bleed Monitoring Computer
BNR
Binary BOT
Begin of Tape BP
Bottom Plug
BRG
Bearing
BRK
Brake
BRKR
Breaker
BRKT
Bracket BRT
Bright, Brightness
BSCU
Braking/Steering Control Unit BTC
Bus Tie Contactor
BTMU
Brake Temperature Monitoring Unit BTN
Button BTR
Bus Tie Relay BU
Battery Unit BUS
Busbar
BYDU
Back-Up Yaw Damper Unit C
Close C
Celsius, Centigrade C/B
Circuit Breaker C/L
Check List