MD-11 Flight Crew Operations Manual
k
Automatic Flight -
Description and Operation
Auto.10.6
• AP engagement is inhibited on the ground and below 100 feet AGL. An
engage attempt will result in an AP disconnect warning.
• AP engagement above 100 feet engages the AP takeoff mode if an FD is
in the takeoff mode.
• For AP engagement with both FDs selected off, the AP will roll the
aircraft to wings level and hold the wings level heading. The altitude hold
mode is also engaged if the rate of climb/descent is below 300fpm;
otherwise the vertical speed mode is engaged and the AP holds either the
vertical speed or the pitch limit (+25 degrees and -10 degrees).
If the AP is engaged with either or both FDs on, the AP will:
• Engage in the existing FD mode and maneuver the aircraft within the
attitude limit to acquire and track the FD mode if the engaged FD mode is
heading/track select, level change speed select, pitch TO/GA, FMS NAV,
or FMS PROF.
• Engage in the existing FD mode if the engaged mode is altitude capture or
glideslope engage. If the pitch command error exceeds limits, the AP will
synchronize the AP/FD to the existing vertical speed flight path angle and
engage the V/S-FPA mode.
• Engage in the existing FD mode and synchronize the AP/FD reference to
existing conditions if the engaged FD mode is V/S-FPA, altitude hold, or
level change speed on pitch hold.
• Roll the aircraft toward wings level then engage the AP heading/track
hold mode when the bank angle decreases to less than 3 degrees if the
engaged FD mode is heading track hold or roll TO/GA. If the AP is
engaged when the bank angle is less than 3 degrees, the AP will
synchronize the AP/FD reference to the existing heading/track angle and
engage the heading/ track hold mode.
• Engage in the localizer mode if the engaged mode is LOC engage and the
FD roll attitude command error is less than 3 degrees. If the FD roll
attitude command exceeds 3 degrees, the AP will roll the aircraft towards
wings level, then engage the AP heading/track hold mode when the bank
angle lessens to less than 3 degrees.
Autopilot Disconnects
The primary method of disconnecting the APs is by pushing either pilot's
disconnect button on the respective control wheel. AFS OVRD OFF switches are
provided on the FCP to disconnect the AP/AT if the normal disconnect switches
fail. All AP disconnects, intentional or unintentional, will result in an AP OFF
warning.
RCWS and certain other FCC functions are inhibited during an AP disconnect
button push.
AP disconnects will also occur as follows:
• Excessive force is applied to the controls.
October 02, 2006
To Next Page
Loading...