- B -

BALANCED CONTROL SURFACE - A movable control surface having an added physical extension or weights forward of the hinge-point to reduce control forces on a yoke or joystick.

BALLOON - A lighter-than-air aircraft that is not engine driven, and that sustains flight through the use of either gas buoyancy or an airborne heater.

BASIC OPERATING WEIGHT (BOW) - Empty weight typically equipped + unusable fuel and trapped liquids + 2 pilots (400 lbs.) + supplies.

BEACON - A device, usually based on the ground that aids in determining position or direction.

BEAM WIDTH - The included angel of a weather radar interrogation signal.

BEARING - Direction on a compass.

BERNOULLI EFFECT - Since the pressure of a fluid is proportional to its velocity, airflow over the upper surface of an airfoil causes an area of negative pressure (lift) because the airstream has been increased in relation to the positive pressure of the airflow on the lower surface.

BIAS - An offset applied to a measurement for error correction.

BLEED AIR - Hot air at high pressure, usually from the bypass section of a gas turbine engine, for de-icing, heating, pressurization and other uses.

BRAKE HORSEPOWER - means the power delivered at the propeller shaft (main drive or main output) of an aircraft engine.