MD-11 Flight Crew Operations Manual
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Flight Controls Chapter Flt
Description and Operation Section 10
Flt.10.1
Flt.10 Flight Controls-Description and Operation
General
All primary and secondary flight controls are hydraulically powered, each by at
least two, and in some cases, by all three airplane hydraulic systems.
Primary flight controls consist of the ailerons (inboard and outboard), the
elevators (inboard and outboard), and the upper and lower two-segmented
(forward and aft) rudders.
Secondary flight controls consist of the trailing edge flaps (inboard and outboard),
leading edge slats (inboard and outboard), combination speed brakes/spoilers, and
an adjustable horizontal stabilizer.
Flight control positions are displayed on the System Display (SD) by selecting the
configuration page with the CONFIG cue switch. In addition to the SD, flap and
slat positions are also shown on the Primary Flight Display (PFD). Alerts will
appear on the Engine And Alert Display (EAD) and SD.
Lateral Control System
The lateral control system consists of inboard and outboard ailerons, augmented
on the downward moving wing by spoilers operating in proportion to control
wheel displacement and/or spoiler input.
The lateral control system is a full power system. Pilot control wheel motion is
transmitted to hydraulic actuators by a closed cable system. No aerodynamic
feedback is provided to the pilot for load feel. Load feel is mechanically provided.
The left-hand inboard aileron and the outboard ailerons of both wings are powered
by hydraulic systems 2 and 3. The right-hand inboard aileron is powered by
hydraulic systems 1 and 3.
When the flaps, slats, and landing gear are retracted, a lockout mechanism keeps
the outboard ailerons faired (neutral) to avoid wing twist. In this case lateral
control is provided by the inboard ailerons and the lateral function of the spoilers.
As the airplane slows down, the outboard ailerons unlock with flaps extended to
15 degrees, or with slats extended, or with landing gear down and locked.
Longitudinal Control System
The longitudinal control system consists of inboard and outboard elevators. Each
surface is powered by two of the three hydraulic systems. The elevator segments
respond to commands from the flight crew, the Longitudinal Stability
Augmentation System (LSAS), and the autopilot.
October 02, 2006
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