L'HOTELLIER
COMPONENT MAINTENANCE MANUAL
12589-( )
PRINTED IN FRANCE
26-20-50
Page 1
APR 01/11
DESCRIPTION AND OPERATION
TASK 26-20-50-870-801-A01
1. Description
A. General
This document describes the Fire Extinguisher (FE) P/N 12589-01 and gives information relating
to its maintenance.
B.
Detailed Description (Refer to Figure 1)
The FE is called "container" in the pages that follow. The container is a DUAL outlet steel
sphere. A fill and safety fitting and a pressure gauge are fusion welded to the container
weldment and a disc assembly is fusion welded in each neck. This causes the container to be
hermetically sealed. A discharge head is installed on each neck.
Each discharge head has a debris screen and a threaded hole. The electrically operated
explosive cartridge is installed in this threaded hole.
The container is filled with a liquid fire-extinguishing agent, bromotrifluoromethane (CBrF
3
),
and pressurized with nitrogen (N
2
). The disc assembly in the neck keeps the extinguishing
agent and nitrogen in the container.
The pressure gage continuously monitors the pressure in the container.
The filling and safety relief valve is used to fill and remove the extinguishing agent of the
container.
When the container is installed in the helicopter and connected to the discharge lines, the
electrically actuated explosive cartridges mounted on the discharge heads are used to break the
disc assemblies to release the extinguishing agent.
TASK 26-20-50-870-802-A01
2. Operation
A.
The container is pressurized to 4100 to 4295 kPa (595 to 623,5 psig) to get the force that is
necessary to push the extinguishing agent from the container. The extinguishing agent and the
nitrogen are kept in the container by the disc until the explosive cartridge fires.
B.
When the explosive cartridge fires, the disc assembly breaks. The nitrogen pushes the
extinguishing agent out of the container. The extinguishing agent goes through the discharge
head to the fire-extinguishing-system tubing. The debris screen keeps the broken pieces of the
disc assembly in the discharge head.
C. The disc assembly in the neck will break when the pressure in the container is more than the usual
operating pressure. This will release the extinguishing agent through the discharge head and
prevent damage to the container from too much pressure. The disc will break when the pressure in
the container is increased to between 16000 and 18500 kPa at +140°C (2320 and
2683 psig at +248°F).
The document reference is online, please check the correspondence between the online documentation and the printed version.
