Honeywell SPZ-8000 - 21 Back Course Mode Intercept

SPZ--8000 Digital Integrated Flight Control System
A28--1146--055
REV 2
Modes of Operation
8-26
When the back course mode is selected on the flight guidance
controller, logic in the flight guidance computer internally reverses the
polarity of the course error and localizer signals, as shown in Figure
8--21. A gain change takes place in the computer when BC is selected,
since the aircraft is closer to the localizer transmitter by the length of the
runway plus 1000 feet.
Back Course Mode Intercept
Figure 8--21