AT  (1) Air Traffic 
(2) Air Transport 
ATA  Air Transport Association 
ATC  Air Traffic Control 
ATCA  Air Traffic Control Association 
ATCC  Air Traffic Control Center 
ATCRBS  Air Traffic Control Radar Beacon System 
ATCSCC  ATC System Command Center 
ATCSS  Air Traffic Control Signaling System. A system to pro-
vide information between the pilot and air traffic con-
trol using the VHF communications transceiver in 
conjunction with data link equipment. 
ATCT  Airport Traffic Control Tower 
ATE  Automatic Test Equipment 
AT&E  Collins Advanced Technology & Engineering 
ATFM  Air Traffic Flow Management 
ATIS  (1) Automatic Terminal Information System 
(2) Automatic Terminal Information Service 
ATLAS  Abbreviated Test Language for Avionics Systems 
ATM  Air Traffic Management 
ATN  Aeronautical Telecommunications Network 
ATNP  Aeronautical TelecommunicationsNetwork Panel 
ATOMS  Air Traffic Operations Management System 
ATP  (1)Acceptance Test Procedure (Air Transport) 
(2) FAA Air Traffic Rules and Procedures Service 
ATR  Air Transport Racking 
ATS  (1) Autothrottle System 
(2) Air Traffic Services 
(3) Air Turbine Starter 
ATSC  Air Traffic Services Communication 
ATSU  ATS Unit 

ATT  Attitude