MD-11 Flight Crew Operations Manual
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Engines -
Description and Operation
Eng.10.4
Both idle modes are controlled by the ECU.
Thrust Control Module (TCM)
General
The TCM is installed in the forward pedestal and contains all the mechanisms to
provide completely electronic signaling (fly-by-wire) between the throttles and
the engines. Pilot controls on the TCM include:
• Throttles.
• ENG START switches.
• Engine FUEL switches.
Throttles
Thrust is set by N1.
The three throttles are driven manually by the pilot or automatically by the
autothrottle system (ATS). The ATS operation can be overridden by the pilot at
any time.
Forward travel of the throttles is limited by an overboost stop. This stop has a
detent that allows continued forward movement of the throttles when they are
pushed with a strong force. This extra forward travel causes the following:
• ATS disconnects.
• FMS thrust is overridden.
• ECU provides maximum emergency thrust (alternate mode).
• An ENG (1, 2, or 3) FADEC ALTN alert is displayed.
Each throttle has an attached piggyback lever to control reverse thrust.
Miscellaneous
Inside the TCM the following items are installed:
• Three position sensors (resolvers) to electronically transmit throttle
position to one of the two ECU channels.
• Engine 1 and 3 thrust reverser interlocks to prevent application of reverse
thrust until the reverser is deployed (nosewheel ground sensing is used for
engine 2).
• Autothrottle servo to transmit ATS commands to the throttles.
Ignition System
Each engine ignition system consists of two independent ignitors (A and B). The
ignitors ignite the fuel/air mixture during starting and provide continuous ignition
during takeoff, landing, and when using engine anti-ice. The ignitors use 115-volt,
400 Hz power.
October 02, 2006
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