Cessna 172SPHUSR05 Pilot Operating Handbook page 356

SECTION 9 - SUPPLEMENTS
SUPPLEMENT 7 - FAA APPROVED
Note that the emergency procedure for any malfunction is essen­
tially the same: immediately grasp the control wheel and regain air­
plane control while pressing and the holding the AlP DISC switch
down.
It is important that all portions of the autopilot system are preflight
tested prior to each flight in accordance with the procedures
published herein in order to assure their integrity and continued safe
operation during ffight.
A flashing mode annunciation on the face of the autopilot is
normally an indication of mode loss.
An exception to this is HDG annunciation which will flash for
5 seconds along with steady NAVARM, APRARM, or
REV ARM annunciation to remind the pilot to set the HDG
bug for course datum use.
1 . Flashing HDG -- Indicates a failed heading.
button to terminate flashing. ROL will be displayed.
2. Flashing NAV, APR or REV -- Indicates a flagged navigation
source. If no NAV source is flagged, a failed heading mode
can be the cause.
terminate flashing. ROL will be displayed.
At the onset of mode annunciator flashing, the autopilot
has already reverted to a default mode of operation,
(Le., ROL mode).
the lost mode may be made if the offending navigation
flag has cleared.
I
Effects of instrument losses upon autopilot operation:
1 . Loss of the artificial horizon -- no effect on the autopilot.
2. Loss of the turn coordinator -- autopilot inoperative.
87-12
NOTE
PRESS NAV, APR or REV button to
NOTE
An immediate attempt to reengage
CESSNA
MODEL 1 72S
PRESS HDG
Mav 30/00