S-TEC System 55X, Operating Handbook

Page: 31 / 56

4-22 2nd Ed: May 31, 2002
SYS FIFTY FIVE X POH
4.3.3 Pilot Selectable Intercept Angles (Standard DG)
The pilot may select an angle of intercept less than the standard 45
!
.
Place the heading bug on the DG to the desired heading used for the
course intercept and simultaneously push both HDG and NAV switches.
HDG, NAV, and APR will be displayed on the autopilot annunciator.
The selected heading will now be flown until the autopilot computes that
an on course turn must be made to minimize overshoot at the point of
intercept. At the time the on-course turn begins, the HDG Mode will
extinguish and you must move the heading bug to match the localizer
course.
NOTE:
Intercept angles greater than 45
!
usually result in
some course overshoot, depending on the distance
from the station and aircraft speed. Therefore, angles
greater than 45
!
are not recommended.
4.3.4 Procedure Turn Localizer Approach (Optional HSI)
Select the appropriate localizer frequency. Set the course pointer to the
INBOUND localizer course and engage the Reverse (REV) Mode to track
the localizer front course outbound or back course inbound.
When a localizer is channeled and REV Mode is selected, the system will
automatically execute high sensitivity gain for the approach and APR and
REV will be displayed on the autopilot annunciator.
If the course needle is at full-scale deviation, the autopilot will establish
a 45
!
intercept angle. As the localizer course is approached, the autopilot
senses the closure rate and gradually shallows the intercept angle. The
inbound turning point is variable, depending on aircraft position and
closure rate to the course. However, the turn will always begin between
100% (full-scale) needle deflection and 20% of full-scale.