Aeronautical Terms beginning with B

Balanced Laterally

Balanced in such a way that the wings tend to remain level.

Ballast

A weight installed or carried in an aircraft to move the center of gravity to a location within its allowable limits.

Basic Empty Weight

(GAMA) Standard empty weight plus optional equipment.

Basic Operating Index

The moment of the airplane at its basic operating weight divided by the appropriate reduction factor.

Basic Operating Weight (BOW)

The empty weight of the aircraft plus the weight of the required crew, their baggage and other standard item such as meals and potable water.

Bilge Area

The lowest part of an aircraft structure in which water and contaminants collect.

Butt (or buttock) Line Zero

A line through the symmetrical center of an aircraft from nose to tail. It serves as the datum for measuring the arms used to determine the lateral CG. Lateral moments that cause the aircraft to rotate clockwise are positive (+) , and those that cause it to rotate counterclockwise are negative (-).