737 Flight Crew Operations Manual
Automatic Flight -
System Description
Boeing Proprietary. Copyright © Boeing. May be subject to export restrictions under EAR. See title page for details.
D6-27370-866-EGP 4.20.3
• loss of electrical power or a sensor input which prevents proper
operation of the engaged A/P and mode
• loss of respective hydraulic system pressure.
Note: Loss of the system A engine-driven hydraulic pump, and a heavy demand
on system A, may cause A/P A to disengage.
AFS Failures
Power interruption or loss may cause disengagement of the AFDS and/or A/T.
Re–engagement is possible after power is restored.
Dual channel A/P operation is possible only when two generators are powering the
busses.
Two independent radio altimeters provide radio altitude to the respective FCCs.
With a radio altimeter inoperative, the autopilot will disconnect two seconds after
LOC and GS capture.
Flight Director Display
Turning a F/D switch ON displays command bars on the respective pilot’s attitude
indicator if command pitch and roll modes are engaged. If command pitch and roll
modes are not engaged, the F/D command bars do not appear. The F/Ds can be
operated with or without the A/P and A/T. F/D command modes can be used with
an A/P engaged in CWS.
F/D commands operate in the same command modes as the A/P except:
• the takeoff mode is a F/D only mode
• dual F/D guidance is available for single engine operation
• the F/D has no landing flare capability. F/D command bars retract from
view at approximately 50 feet RA on an ILS approach.
Normally, FCC A drives the captain’s command bars and FCC B drives the first
officer’s command bars. With both F/D switches ON, the logic for both pilots’
F/D modes is controlled by the master FCC, and both FMA displays show the
same mode status.
The master FCC is indicated by illumination of the respective master (MA) F/D
indicator light. The master FCC is determined as follows:
• with neither A/P engaged in CMD, the FCC for the first F/D turned on is
the master
• with one or both A/Ps engaged in CMD, the FCC for the first A/P in
CMD is the master FCC, regardless of which F/D is turned on first.
September 15, 2016
To Next Page
Loading...
