S-TEC Fifty Five X - Pilot Selectable Intercept Angle; AP Display, HDG Mode Engaged, REV APR Mode Armed

3rd Ed. Sep 30, 06 3-17
S–TEC
3.3.1.1 Pilot Selectable Intercept Angle
To select an intercept angle, set the Heading Bug to the desired intercept
heading on the compass card, such that the difference between this heading
and the BACK INBOUND LOC course is the intercept angle. If the heading
system is an HSI, set the Course Pointer to the FRONT INBOUND LOC
course on the compass card.
Press and hold the HDG mode selector switch, and then press the REV mode
selector switch to engage the heading mode and arm the reverse approach
mode. The HDG, APR, and REV annunciations will appear as shown in Fig.
3-23, to acknowledge this.
The autopilot will establish the aircraft on the selected intercept angle
(heading), until it must turn the aircraft onto the BACK INBOUND LOC course to
prevent overshoot. At that point in the intercept sequence, the HDG annunciation
will extinguish to indicate engagement of the reverse approach mode. At the
moment this occurs, if the heading system is a DG, immediately set the Heading
Bug to the BACK INBOUND LOC course, in order to input a course error to the
autopilot. Otherwise, the autopilot will lack sufficient authority to turn the aircraft
onto the course.
Fig. 3-23. AP Display, HDG Mode Engaged, REV APR Mode Armed