BAI Battlefield air interdiction
ballistic parachute Emergency recovery parachute, usually for light aircraft or microlights
BAPC British Aircraft Preservation Council
bar Unit of pressure (non-SI); ISA pressure at sea level is 1.0132 bar
battle damage In flight damage directly caused by enemy action
BDA Bomb damage assessment
BCAR British Civil Airworthiness Requirements
BDLI Bundesverband der Deutschen Luftfahrt-, Raumfahrt- und Ausrüstungsindustrie; German Aerospace Industries Association
BDR Battle damage repair
Beta mode Operating regime of propeller or rotor where pilot has direct pitch control of blades
BG Bomb Group (USAF)
BHP Brake horsepower
bingo (fuel) Radio call indicating aircraft has critical (low) fuel state
BIT Built-in test
BITE Built-in test equipment
bladder tank Flexible fuel tank, not part of airframe
blade damper Device which restrains motion of a helicopter blade about drag hinge, reduces noise and vibration
BLC Boundary layer control; control of layer of air in contact with aircraft surface (usually upper wing surface) to increase lift, reduce drag or improve controllability
bleed air Compressed air taken from jet engines to perform useful function
Blimp Non-rigid airship
blind flying Flying without outside visual reference, only using instrumentation
blisk Complete compressor stage on a jet engine, manufactured as a single part
block time Period of time between when aircraft starts to move off the apron (with the intention to take-off) to the time it comes to rest again
blown flap Flap across which bleed air is blown at high speed to prevent airflow breakaway
BLU Bomb live unit
BMEWS Ballistic missile early warning system (US)
BPR Bypass ratio
BRS Ballistic Rescue System; parachute designed to save aircraft in emergency
BRW Brake release weight; maximum allowable weight at start of take-off run
BS Bomb squadron (USAF)
buddy-buddy pack In-flight refueling equipment carried on aircraft weapons pylon in a streamlined container
bulk cargo Loose freight which is not palletised or containerised
bus or busbar Main electrical system to which generator or battery power is supplied
BVR Beyond visual range
BW Bomb wing (USAF)
BWB Blended wing/body
bypass ratio On a turbofan engine: the air that goes around the engine core divided by the air that goes through the engine core
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