KLM MD-11 - Electrically Controlled Slat System; Lateral Trim System

MD-11 Flight Crew Operations Manual
k
Flight Controls -
Description and Operation
Flt.10.8
Electrically Controlled Slat System
An electrically controlled slat system replaces the cable controlled system. With
this system FLAP/SLAT handle operation is simplified as follows:
• Operating forces are less.
• Operation is single path, up-and-aft to extend; up-and-forward to retract.
• There is no go-around type gate at the 0/EXT detent.
• The blue dot maintenance detent is plugged.
The 28-volt right emergency DC bus and the 28-volt DC bus 2 power the system.
The electrical slat control modification consists of:
• Adding switches in the cockpit flap/slat module for slat command, handle
position, and speed/Mach inhibit override.
• Adding two electrically operated hydraulic valves in the CAC, one for the
inboard slats and one for the outboard slats.
• Adding wiring between the switches and valves.
• Deleting slat cable control linkage from the flap/slat module.
• Deleting the slat stow lever and linkage.
• Deleting the FLAP/SLAT handle latch and gate cover.
At extension, both inboard and outboard slats begin to extend simultaneously. At
retraction, both inboard and outboard slats begin to retract simultaneously. The
inboard slats retract at a slower rate and are approximately half retracted when the
outboard slats are fully retracted.
An added feature to the system is a slat extension inhibit system. The inhibit
system prevents slat extension at speed of 280 knots/.55 Mach or greater. This
system uses a signal from any one of the three DEUs. At flap settings of 10° or
more, the system is deactivated. The autoslat system is not affected by this system.
A SLAT STOW switch, located on the forward pedestal, deactivates slat
extension and illuminates amber when activated. The flaps operate normally as
selected with slats deactivated.
Lateral Trim System
Lateral trim, driving aileron and spoiler actuators through a cable system, is
accomplished with the aileron trim knob on the center pedestal.
When the trim knob is moved, the neutral point of the ailerons is repositioned. If
more than 5 degrees of aileron trim is commanded, the lateral control spoilers
begin to deflect upward, as required, to provide additional trim. Spoiler trim
motion is limited to 6 degrees.
Aileron trim is indicated on the aileron trim indicator, the surface position
indicator, and by physical displacement of the control wheel.
October 02, 2006