KLM MD-11 - Engine and APU Fire Extinguishing

MD-11 Flight Crew Operations Manual
k
Fire Protection -
Description and Operation
Fire.10.6
The APU FIRE handle and the alert on the EAD will continue to stay on as long
as the warning exists
The APU will automatically shut down when a fire is detected and the APU FIRE
light on the external panel will flash.
The ENG/APU FIRE TEST button on the APU control panel sends a voltage input
simulating a fire signal for loops A and B. This tests FDCU circuitry for the output
drives for the fire bell, FIRE handle, MASTER WARNING and FUEL switch
lights, aural warning, and level 3 ENG/APU FIRE alert. This does not test loops
A and B.
The FDCU continuously monitors the loops. If the FDCU detects both engine or
APU loops on a single element are faulty, the alert FIRE DET (1, 2, 3, APU) FAIL
will be displayed. If only one of the two engine or APU loops (A or B) on a single
element is detected faulty, the alert FIRE DET (1, 2, 3, APU) FAULT will be
displayed.
The FIRE DET (1, 2, 3, APU) FAULT alert is common for a single loop fault (A
or B) for any of the engine elements or APU. It indicates that the fire detection
system for engines and APU is operative even though one loop is inoperative.
Engine and APU Fire Extinguishing
The engine/APU fire extinguishing system is a chemical (Halon 1301) high rate
discharge system used to extinguish fires in the engine and APU compartments.
The system is powered by the battery direct bus.
Each extinguishing system consists of two stainless steel agent bottles, discharge
heads, discharge cartridges with electrical connectors, agent distribution system,
cockpit controls and displays, and warning lights.
In case of bottle overpressure, a disk will rupture and agent will flow to the
respective zone.
Agent discharge is not automatic.
Two bottles located in the rear fuselage provide agent for the aft engine (engine 2)
and APU fire zones. Each bottle has two outlets, allowing discharge to the selected
fire zone, with provision for the second bottle to discharge to the same fire zone,
if necessary.
When both engine 2 fire agents have been discharged to the APU, none remains
for engine 2.
Two identical bottles are located in each wing inboard of the pylon near the front
spar. They provide agent for each of the pylon mounted engine fire zones.
Each bottle has two outlets, one of which is capped. The uncapped outlets are
connected together to allow discharge to the same fire zone.
November 10, 2008