Cessna SkyHawk SP 172S NAV III 2005 Pilot Operating Handbook page 359

SECTION 9 • SUPPLEMENTS
SUPPLEMENT 3
CESSNA
MODEL 172S NAV III
NORMAL PROCEDURES
(Continued)
3. POWER· SET as applicable for vertical speed selection.
NOTE
The autopilot can hold a set vertical speed only if
engine power and airplane weight are correct for the
conditions. If the vertical speed set for the autopilot
is more than the airplane can supply and airspeed
decreases sufficiently, the airplane can be made to
stall. Make sure that the vertical speed set for the
autopilot results in airplane performance that stays
in the operating limitations of both the autopilot and
the airplane.
ALTITUDE PRESELECT MODE (ALTITUDE LOCK ON).
1.
ALTITUDE SELECT· SET target altitude using knob on
KAP 140.
2. ALTITUDE ARM • PUSH the ARM button to set the Altitude
Lock On feature to the ON position (if needed). ALT ARM
will show on the face of the autopilot when Altitude Lock On
is set to the ON condition.
NOTE
• Minor differences between the autopilot altitude
selection and the airplane altitude indication may
be seen after altitude lock on. This small
difference is generally due to autopilot system
tolerances.
• Use of Altitude Preselect (Lock On) mode is not
recommended for lock on at minimum descent
altitude (MDA) during non-precision instrument
approach procedures due to the possibility of
altitude overshoot. Glideslope (GS) lock on
during an ILS approach will prevent lock on to a
preselect altitude selection.
• Use Vertical Speed mode as described previously
in CLIMB or DESCENT for altitude change.
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S3·30 U.S.
FAA APPROVED
172SPHAUS-S3-00