Boeing 787-8 - Page 808

787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Flight Controls -
System Description
Copyright © The Boeing Company. See title page for details.
9.20.8 D615Z003-TBC
Flight Control System Direct Mode
The ACEs automatically transition to the direct mode when they detect the failure
of all three PFCs or lose communication with the PFCs. The direct mode can also
be manually selected by moving the PRIMARY FLIGHT COMPUTERS
disconnect switch to DISC.
In the direct mode, the PFCs no longer generate control surface commands. Pilot
inputs received by the ACEs are sent directly to the control surface actuators.
The direct mode provides full airplane control for continued safe flight and
landing. The airplane handling qualities are almost the same as the secondary
mode. All flight control surfaces remain operable and yaw damping is degraded.
The EICAS caution message PRI FLIGHT COMPUTERS is displayed when the
system is in the direct mode.
In the direct mode, the following functions are not available:
Direct Mode
• autopilot
• auto speedbrakes
• gust suppression
• overspeed protection
• roll/bank angle protection
• roll/yaw asymmetry compensation
• stall protection
• tail strike protection
Surfaces
Control
SPOILERS
RUDDER
FLAPERONS
AILERONS
ELEVATORS
STABILIZER
Pilot Control Inputs
control in each axis
Provide redundant
ACEs
ACTUATOR
ELECTRONICS
CONTROL
AUTOPILOTS
COMPUTERS
PRIMARY
FLIGHT
Not available Not available
February 15, 2010