Textron 172R180HP, Pilot Operating Handbook

Page: 323 / 396

CESSNA
MODEL 172R
SECTION 9 - SUPPLEMENTS
SUPPLEMENT 5 - FM APPROVED
6.
NAV/GPS
SWITCH -- Toggles from Nav 1 to GPS and vice
versa to control the type of navigation data to be displayed on
the COi (Course Deviation Indicator). The No. 1 COi Omni
Bearing Selector (OBS) provides analog course input to the
KLN 898 in OBS mode when the NAV/GPS
switch/annunciator is in GPS. When the NAV/GPS switch
annunciation is in
NAV,
GPS course selection in OBS mode is
digital through the use of the controls and display at the KLN
898.
NOTE
Manual COi course centering in
OBS
mode using the
control knob can be difficult, especially at long
distances. Centering the Course Deviation Indicator
(COi) needle can best be accomplished by pressing the
Direct-To button and then manually setting the No. 1
COi course to the course value prescribed in the KLN
89B displayed message.
NOTE
The Directional Gyro heading (HOG) bug must also be
set to provide proper course datum to the autopilot if
coupled to the KLN 898 in
LEG
or
OBS.
(When the
optional HSI is installed, the HSI course pointer provides
course datum to the autopilot.)
7. NAVIGATION SOURCE
(NAV)
ANNUNCIATOR -- The
NAV
annunciator will illuminate steady to inform the pilot that NAV
1 information is being displayed on the NAV 1 COi.
8. NAVIGATION SOURCE (GPS) ANNUNCIATOR -- The GPS
annunciator will illuminate steady to inform the pilot that GPS
information is being displayed on the NAV 1 COi.
Figure 1. GPS Annunciator/Switch (Sheet 3 of 3)
July 15/98
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