REMAINS MCHENG UNTIL EXITCONFIGURATION IS COMPLETEGO AROUND TRACKHOLD GROUNDCONTROLS TO CONTROLS FORSAFE CLIMB RATEUSING SPEED/FLAPS REF CONTROLS TOHOLD GROUNDTRACK
LEFT A/PAS FOR
AS FORLEFT A/P
L A/P ASSUMED TO BE CMDENG INITIALLY.
1
C OR R A/P COULD ALSO BE CMD INITIALLY.
Autoland Functional SequenceFigure 13 (Sheet 2)
A70355
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757 MAINTENANCE MANUAL
GUN 051; multichannel engage occurs when all A/Ps have detected LOC and G/S capture and 1500 feet from a valid radio altimeter (RA). The first channel in command must receive acceptable CMDENG criteria from the other two FCCs. All A/Ps engage pitch, roll, and yaw channels. The ASA displays AUTOLAND 3 (Fail Operational) or AUTOLAND 2 (Fail Passive). All phases of autoland are possible with AUTOLAND 3 or AUTOLAND 2 displayed.If the current first-channel-in-command cannot provide autostabilizer trim control, automatic selection of a new first-in-command is made by a prescribed sequence (i.e., L, R, C, L...).GUN 001-050, 052-999; if a critical sensor fails during a Fail-Operational approach, the ASA shows NO LAND 3, and the FMA displays a mode fault annunciation. When the pilot presses the ASA reset, the AFDS reverts to a FAIL-PASSIVE approach and the ASA displays LAND 2.GUN 051; if a critical sensor fails during a Fail-Operational approach, the ASA shows AUTOLAND 2, and the FMA displays a mode fault annunciation. When the pilot presses the ASA reset, the AFDS reverts to a FAIL-PASSIVE approach and the ASA displays AUTOLAND 2 and the FMA removes the mode fault annunciation.The A/P channel having its own dedicated sensor invalid selects a valid equivalent sensor input from the cross-channel data bus and the A/P remains MCHENG. If this channel is FIRST IN CMD, it remains FIRST IN CMD. Loss of two similar sensor signals disables autoland capability. The autopilot disengages and the ASA goes blank. The FMA displays fault modes.Single channel A/P disconnect causes the autoland configuration to revert to FAIL-PASSIVE.In single channel ILS approach, no runway alignment, flare, or rollout control or guidance is available.The Autoland configuration is normally disconnected by pressing the A/P disconnect switch on either control wheel just before runway turnoff. It is automatically disconnected by an ENGAGE REMOVAL FAULT.When disconnect warnings occur, they must be reset. The A/P disengage warning reset depends on whether the one-push or two-push option is active. The autopilot stays in a multichannel configuration when Go-Around (GA) is selected. When exit from GA occurs, MCHENG reverts to single channel CMDENG (FIRST IN CMD).
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757
MAINTENANCE MANUAL
(9) Control and Display
(a) Control
1) AIRPLANES WITH CONTROL WHEEL STEERING; two A/P ENGAGE modes are available for selection on the MCP, CWS and CMD. The pilot can assume control of the airplane in the Control Wheel Steering (CWS) mode by pressing the CWS switch/light. Automatic navigation is available from selectable reference sources in single channel CMD engage for climbout, cruise, descent, and ILS approach.
2) AIRPLANES WITHOUT CONTROL WHEEL STEERING; automatic navigation is available from selectable reference sources in single channel CMD engage for climbout, cruise, descent, and ILS approach.
3) When two or three A/P channels are engaged in CMD, Autoland approaches are possible.
4) The autopilot is not certified for takeoff. The takeoff mode is a Flight Director only mode.
5) AIRPLANES WITH CONTROL WHEEL STEERING; in A/P stand-alone (no F/D is on) operation, Lateral Navigation (LNAV) is accomplished through the following modes: heading hold, heading select, localizer only, approach guidance and rollout, roll control wheel steering, and turbulance penetration.
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