AOHE  Air/Oil Heat Exchanger 
AOPA  Aircraft Owners and Pilots Association 
AOPG  Aerodrome Operations Group 
AOR  Atlantic Ocean Region 
A/P  Autopilot. A computer commanded system for con-
trolling aircraft control surfaces. 
APA  Autopilot Amplifier 
APALS  Autonomous Precision Approach and Landing System 
APANGPRIG  ICAO Asia/Pacific Air Navigation Planning and 
Implementation Regional Group 
APB  Auxiliary Power Breaker 
APC  (1) Autopilot Computer 
(2) Aeronautical Public Correspondence 
APEX  IMA Application/Executive Software Interface 
APP  Approach Control 
APPR  Approach 
APU  Auxiliary Power Unit 
APUC  Auxiliary Power Unit Controller 
AQP  Avionics Qualification Procedure 
A-QPSK  Aeronautical Quadrature Phase Shift Keying 
AQS  Advanced Quality System 
ARA  FAA Research and Acquisitions 
ARES  Advanced Railroad Electronics System 
ARINC  Aeronautical Radio,Inc. 
ARF  Airline Risk Factor 
ARP  Air Data Reference Panel 
ARS  Automated Radar Summary chart. These are hourly 
generated charts showing location and intensity of 
radar echoes. 
ARSR  Air Route Surveillance Radar 

ART  Automatic Reserve Thrust 
ARTCC  Air-Route Traffic Control Center. Approximately 20 
centers cover the air traffic routes in the United 
States using numerous radars and radio communica-
tion sets. 
ARTS  Automated Terminal Radar System 
ASA  (1) Autoland Status Annunciator (AFDS) 
(2) Aircraft Separation Assurance