Textron Aviation Cessna 172S NAV III Skyhawk SP, Information Manual

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CESSNA SECTION 7
MODEL 172S NAV III AIRPLANE AND SYSTEM DESCRIPTION
KAP 140 AUTOPILOT
U.S.
FLIGHT INSTRUMENTS
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HORIZONTAL SITUATION INDICATOR
The Horizontal Situation Indicator (HSI) is found along the lower center
area of the PFD. The heading indication data is provided by the AHRS
and magnetometer units. The HSI combines a stabilized magnetic
direction indicator (compass card) with selectable navigation deviation
indicators for GPS or VHF navigation. The HSI is conventional in
appearance and operation.
Magnetic heading is shown numerically in a window centered above
the heading index (lubber line) at the top of the HSI. Reference index
marks are provided at 45° intervals around the compass card. A
circular segment scale below the heading window at the top of the HSI
shows half and standard rates of turn based on the length of the
magenta turn vector.
The cyan HSI heading reference pointer, bug, is set using the HDG
knob on the GDU display. The selected heading is shown digitally in a
window above the upper left 45° index mark. The selected heading will
provide control input to the autopilot, if installed, when engaged in HDG
mode.
The CDI navigation source shown on the HSI is set using the CDI
softkey to select from GPS, NAV 1 or NAV 2 inputs. The course
reference pointer is set using the CRS knob on the GDU display. The
selected course is shown digitally in a window above the upper right
45° index mark. The selected navigation source will provide control
input to the autopilot, if installed, when engaged in NAV, APR or REV
mode and it is receiving a navigation signal from the selected GPS or
VHF NAV radios.
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172SPHAUS-05 7-19
For
Training
Purposes
Only