BY ORDER OF THE SECRETARY OF THE AIR FORCE AIR FORCE ...

AFMAN 11-217V1 3 JANUARY 2005 79
effect on the CDI display. The CDI displays only if the aircraft is on course
or in a 90- or 150-Hz zone of signals originating from the ILS localizer
transmitter. The CDI always deflects to the left of the instrument case in the
150-Hz zone and to the right in the 90-Hz zone. It centers when the signal
strength of both zones is equal. (Although the course selected has no effect on
the CDI, always set the published inbound FRONT COURSE of the ILS in the
course selector window. This will ensure the heading pointer is directional in
relation to the CDI displacement.
5.2.2.2.2. The glide slope indicator (GSI) displays glide slope position in relation
to the aircraft. If the GSI is above or below center, the glide slope is above or
below the aircraft respectively. Full-scale deflection of the GSI is dependent
upon the width of the glide slope (1.4°). Example: The glide slope width is 1.4°,
full-scale deflection would be .7°, and each dot would be .35° (Figure 5.7).
Figure 5.7. Example of Course and Glide Slope Deviation Indications vs. Actual
Displacement Relative to Distance From Touchdown for a 5°- Wide Localizer and a 1° -
Wide Glide Slope.
5.2.2.2.3. Warning Flags. Appearance of the course or glide slope warning flags
indicate that the course or glide slope signal strength is not sufficient. Absence of
the identifier indicates the signal is unreliable. See Chapter 7 for discussion on
NAVAID identification.
5.2.2.2.3.1. WARNING: It is possible under certain conditions for the CDI
or GSI to stick in any position with no warning flags while reliable station