hydration system

hydration bladder

hydration pack

fire extinguishing system sprinkler system and fire alarm system

merchant ship communication system (mercomm system)

multiple launch rocket system (MLRS); multiple rocket launcher system

Air Force weapons system / AF weapon system

attitude-and-heading reference system / attitude and heading reference system (AHRS)

selective calling system, SELCAL system

Unmanned Aerial System / Uncrewed Aircraf System (UAS)

system of system common operating environment

active denial system

active infrared (IR) guidance system

advanced intercontinental missile system

Advanced Precision Kill Weapon System (APKWS)

AEGIS weapons system

aerodynamic control system

air command and control system (ACCS)

air cooling system

air defense artillery system

air defense guided missile system (AD GM sys)

air electronic guidance information system (AEGIS)

air traffic signalling system

airborne collision avoidance system (ACAS)

Airborne Warning and Control System (AWACS)

aircraft armament system

aircraft gunnery system

aircraft missile system

aircraft’s weapon control system

air-delivered cluster weapons system

air-ground operations system

alarm system

all-embracing system of international security