Cessna TURBO CENTURION T210M 1978 Pilot Operating Handbook page 302

CESSNA 400 GLIDE SLOPE
(TYPE R-443B)
PILOT'S OPERATING HANDBOOK
SUPPLEMENT
2
TYPICAL 300 SERIES GLIDE SLOPE INDICATORS
1. GLIDE SLOPE DEVIATION POINTER - Indicates devia-
tion from normal glide slope.
2. GLIDE SLOPE "OFF" OR "GS" FLAG - When visible,
indicates unreliable glide slope signal or improperly
operating equipment. The flag disappears when a re-
liable glide slope signal is being received.
Spurious glide slope signals may exist in the area
of the localizer back course approach which can
cause the glide slope "OFF" or "GS" flag to dis-
appear and present unreliable glide slope informa-
tion. Disregard all glide slope signal indications
when making a localizer back course approach un-
less a glide slope {ILS BC) is specified on the
approach and landing chart.
Figure 1. Typical 300 Series VOR/LOC /ILS Indicator