787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Automatic Flight -
System Description
Copyright © The Boeing Company. See title page for details.
4.20.10 D615Z003-TBC
and:
• speed less than an FMC calculated value for one second
• thrust below reference thrust
• airplane altitude above 100 feet RA on approach, or airplane barometric
altitude 400 feet above airport on takeoff
Note: During a descent in VNAV SPD, the autothrottle may activate in HOLD
mode and does not support stall protection.
The EICAS advisory message AUTOTHROTTLE L or R is displayed when the
respective autothrottle servo fails. If the autothrottle is active and only one
autothrottle is armed, the PFD autothrottle flight mode annunciation displays L or
R preceding the mode. For example, L SPD indicates only the left autothrottle is
active in speed mode.
Autothrottle Thrust Lever Operation
The autothrottle system moves either or both thrust levers to provide speed or
thrust control, depending on the active mode.
The thrust levers can be manually positioned without disconnecting the
autothrottle. After manual positioning, the autothrottle system repositions the
thrust levers to comply with the active mode. The autothrottle system does not
reposition the thrust levers while in HOLD mode.
Autothrottle Disconnect
The autothrottle system can be disconnected manually by pushing either thrust
lever autothrottle disconnect switch, except during conditions that cause the
autothrottle to automatically activate. The autothrottle can also be disconnected
manually by positioning both A/T ARM switches to OFF, or individually by
positioning the left or right A/T ARM switch to OFF. Positioning one or both A/T
ARM switches to OFF prevents activation of all autothrottle modes for the
affected autothrottle.
Autothrottle disconnect occurs automatically:
• if a fault in the active autothrottle mode is detected
• when either reverse thrust lever is raised to reverse idle
• if the thrust levers are overridden during a manual landing, after the
autothrottle has begun to retard the thrust levers to idle
• when both engines are shut down
The EICAS caution message AUTOTHROTTLE DISC is displayed and an aural
alert sounds when the autothrottle is manually or automatically disconnected. The
EICAS caution message and aural alert are inhibited if the disconnect occurs
because of reverse thrust.
August 14, 2009
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