787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Flight Controls -
System Description
Copyright © The Boeing Company. See title page for details.
9.20.2 D615Z003-TBC
The autopilot sends commands to the PFCs, which then produce control surface
commands. (Refer to Autopilot Flight Director System
in Chapter 4, Section 20,
for additional information.)
Unique Failure Considerations
In the unlikely event of the loss of all hydraulic power, the electrically actuated
stabilizer and two spoiler pairs allow pilot control of pitch and roll using the
primary pitch trim switches, alternate pitch trim switches, and the control wheel.
If there is a complete loss of flight control signaling, direct wiring from the flight
deck to the stabilizer and a spoiler pair allow pilot control of pitch using the
alternate pitch trim switches and roll using the control wheel.
Flight Control Surfaces
Pitch control is provided by:
• two elevators
• a movable horizontal stabilizer
Roll control is provided by:
• two flaperons
•two ailerons
• fourteen spoilers
Yaw control is provided by a single rudder.
The two elevators and horizontal stabilizer work together to provide pitch control.
The flaperons and ailerons provide roll control, assisted by asymmetric spoilers.
The flaperons are located between the inboard and outboard flaps on both wings.
In the normal mode, they are used for roll control with the flaps either retracted or
extended. The flaperons also droop with the trailing edge flaps to improve slow
speed performance.
The ailerons are located outboard of the outboard flaps on each wing. The ailerons
and spoilers droop with the trailing edge flaps to improve slow speed
performance.
The ailerons are locked out during high speed flight where the flaperons and
spoilers provide sufficient roll control. During low speed flight, the ailerons
operate to augment roll control.
Yaw control is provided by a single rudder. During takeoff, the rudder becomes
aerodynamically effective at approximately 60 knots groundspeed.
Flaps and slats provide high lift for takeoff, approach, and landing.
Symmetric spoilers are used as speedbrakes.
February 15, 2010
To Next Page
Loading...
