Cessna SkyHawk SP 172S NAV III 2005 Pilot Operating Handbook page 335

SECTION 9 - SUPPLEMENTS
SUPPLEMENT 3
GENERAL
(Continued)
CESSNA
MODEL 1725 NAV III
A locking device prevents the autopilot or MET from engaging until
the autopilot computer has completed the preflight self-test
sequence and finds that the system is not defective. The preflight
self-test starts when the AVIONICS BUS 2 Switch is set to the ON
position.
The KAP 140 Autopilot will disengage if any of the following
conditions occur:
1. Internal Autopilot System malfunction.
2. Autopilot Computer Monitor detects either R (roll axis) or P
(pitch axis) malfunction annunciation.
3. Pitch accelerations larger than
+
1.4g or - 0.6g caused by
a servo malfunction. The pilot cannot maneuver the
airplane and cause the autopilot to disengage, although
some turbulence can.
4. DC Electric Turn Coordinator malfunction.
5.
The AlP DISCfTRIM INT Switch on the LH Control Wheel is
pushed.
The AVIONICS BUS 2 Switch supplies electrical power to the
AUTO PILOT Circuit Breaker from AVN BUS 2. The AVIONICS
BUS 2 Switch can also de-energize the Autopilot or MET system in
an emergency.
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S3-6 U.S.
FAA APPROVED
172SPHAUS-S3-00