787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Automatic Flight -
System Description
Copyright © The Boeing Company. See title page for details.
D615Z003-TBC 4.20.3
An automatic autopilot disconnect occurs for some failures detected by the
autopilot. The EICAS warning message AUTOPILOT DISC is displayed if the
autopilot is manually or automatically disconnected. Depending upon the system
failure, it may be possible to re–engage an autopilot by pushing the autopilot
engage switch.
Autopilot and Flight Director Mode Degradations
Autopilot
The autopilot system can detect the degradation of a specific autopilot mode.
When an engaged mode degrades, the autopilot remains engaged in an attitude
stabilizing mode based on inertial data. The condition is annunciated on the PFD
and HUD by a line drawn through the affected flight mode annunciation (amber
line on the PFD) and the respective flight director bar is removed from the PFD
and the flight guidance cue is removed from the HUD. The EICAS caution
message AUTOPILOT is displayed to indicate the autopilot is operating in a
degraded mode. When the degradation is no longer present the annunciations
clear, the autopilot resumes using the mode, and a green box is drawn around the
affected flight mode annunciation on the PFD and HUD for 10 seconds.
Flight Director
[Option – Split cue]
When a specific flight director mode degrades, the flight director provides an
attitude stabilizing command based on inertial data. The condition is annunciated
by removal of the affected (pitch or roll) flight director bar and the HUD flight
guidance cue. When the degradation is no longer present the flight director
commands immediately return to view.
ILS Signal Interference Monitor
The autopilot flight director system (AFDS) can detect significant ILS signal
interference due to service vehicles or aircraft. If localizer or glideslope signal
interference is detected, the autopilot disregards the ILS signal and remains
engaged in an attitude stabilizing mode based on inertial data. Most ILS signal
interferences last only a short period of time, so there is no annunciation other than
erratic movement of the ILS raw data during the time the interference is present.
If the condition persists, the annunciations described above for Autopilot and
Flight Director Mode Degradation are provided.
Flight Director Display
The flight director steering indications are normally displayed any time the related
flight director switch is ON.
August 14, 2009
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