Cessna 172R, Operating Handbook

Page: 397 / 500

CESSNA
MODEL 172R
SECTION
9
-
SUPPLEMENTS
SUPPLEMENT
7
-
FAA APPROVED
I
SUPPLEMENT 7
BENDIX/KING KAP
140
SINGLE AXIS AUTOPILOT
SECTION
1
GENERAL
The
Bendix/King
KAP 140 is an all-electric, single-axis
(aileron
control) autopilot
system
that provides lateral and directional control.
Components are a
computer,
a
turn
coordinator, an
aileron
actuator,
a
course
deviation indicator, and a directional indicator or HSI (if
installed).
Roll and yaw
motions of the
airplane are sensed
by the
turn
coordinator gyro. The
computer computes
the necessary correction
and signals the
actuator to
move the ailerons
to
maintain the
airplane in the commanded lateral attitude.
The KAP 140 will provide wing leveler, heading hold, NAV track,
and approach and backcourse lateral modes.
A lockout device
prevents
autopilot
engagement
until the
system
has been successfully preflight tested. Automatic preflight self-test
begins
with initial
power
application
to
the autopilot.
The following conditions will cause the autopilot
to
disengage:
A. Electric power failure.
B.
Internal autopilot
system
failure.
C.
Turn coordinator failure (flagged gyro).
D.
Computer
autopilot monitor that detects the R (ROLL) axis
annunciator.
The AVIONICS MASTER switch supplies
power
to
the avionics bus
- bar
at
the radio circuit breakers and the
autopilot circuit breaker.
The
AVIONICS
MASTER switch also services as an emergency
autopilot (AP) shutoff.
Revision
4
S7-5