coefficient B[¦kō·ə′fish·ənt ′bē]
A component of magnetic compass deviation, varying with the sine function of the compass heading, resulting from the fore-and-aft component of the craft's permanent magnetic field and induced magnetism in unsymmetrical vertical iron forward or aft of the compass.
The coefficient of semicircular compass deviation caused by magnetism in the body of the carrying aircraft along its longitudinal axis. Its value is maximum on easterly and westerly headings. Coefficient B = ¼(Deviation on magnetic East − Deviation on magnetic West).