INTERCEPT PROCEDURES TEXTBOOK
To utilize these two displays effectively, aircrew should envision the fighter's projected flight
path as extending through the center of the BDHI and the scope.
The BDHI and AI Scope
The fighter's flight path runs vertically through the center of the BDHI. The BDHI has left
and right-hand fiducials, located 45° left and right of the center. There are also fiducial markers
at 90ºand 135º left and right of the dead ahead position. The AI scope is a B-scope used to
display azimuth and range of airborne targets.
Think of the AI scope as a big window centered on the longitudinal axis of the fighter, with
the window edges extending out 60º left and right. The angle off (AO) is the angle from the
fighter's flight path (fighter's nose) to the bogey. AO is always stated in degrees right or left.
With the 20 mile range scale selected, the range on the scope is measured from 0 miles at the
base of the scope to 20 miles at the top of the scope, with horizontal lines dividing the scope into
5 increments (in this case, 4 miles each).