MD-11 Flight Crew Operations Manual
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Ice and Rain Protection -
Description and Operation
Ice.10.12
Engine 2 supplies hot bleed air to the engine inlet through a double shrouded
anti-ice duct which runs through the tail. This duct is continuously monitored for
an overheat condition due to a burst or a leak by a Continuous Fire Detection unit
(CFD) and its three associated sensing elements.
The outer shroud of the anti-icing duct is thinner than that of previous airplanes.
NOTE: The CFD does not detect fire, only overheat.
The system consists of the CFD, sensing elements, and the cowl anti-ice valve.
Annunciation of system status is provided by the Environmental System
Controller (ESC), anti-ice control panel, and Electronic Instrument System (EIS).
The CFD is in the center accessory compartment and operates on 28-volt DC
power. There are two overheat sensors below the engine 2 anti-ice duct and one
above the duct.
When an overheat is sensed (about 154°C) the CFD closes the engine 2 cowl
anti-ice valve when commanded on. DISAG illuminates on the ENG 2 ANTI-ICE
switch (valve closed and commanded on). If the valve remains open during the
overheat, due to a failure, the ENG 2 A-ICE DUCT alert is displayed.
A preflight test of the system is initiated when the ANNUN LT TEST button is
pushed until the AIR SYS TEST alert appears. The ENG DUCT TST FAIL alert
is displayed if the overheat detection system detects a preflight test failure.
October 02, 2006
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