11.8a Fire Extinguishing Systems Flashcards
What zones on aircraft have fixed fire detection AND extinguishers
Engine, APU, baggage and cargo compartments, lavatories
What is the most common extinguishing agent
Halon 1301
How is agent released out of the extinguisher bottles
Using pressurised nitrogen
What is the purpose of the temperature/pressure-sensitive safety relief diaphragm
Release bottle pressure in event of high temperatures
What is installed at the outlet of the bottle
Assembly cartridge (squib) and frangible disk (diaphragm)
What is a standard release type extinguisher release
Uses a slug driven by explosive energy to rupture a segmented closure disc
What happens if an extinguisher has low pressure
It will appear on the gauge or, there will be a cockpit warning if the gauge has an electrical connection
What is a two way check valve
Used on twin engined aircraft to prevent agent from a second bottle from backing into a previously emptied bottle
What is a discharge indicator
Provides visual evidence of a bottle discharge
What are the two types of discharge indicator
Thermal discharge (red) and discharge indicator (yellow)
What are the thermal discharge indicator and discharge indicator
Ejecting a red disk for excessive heat and a yellow disk when the crew activated an extinguisher
What must there be on an engine fire extinguishing system
‘Two shot’ system
What happens when engine fire button is pushed
EDG switched off, bleed air valves close, fuel shit off, hydraulic shut off, arms extinguishing bottles
Who operates APU extinguishers
Normally automatic, self monitoring system with automatic extinguishing
What should extinguisher bottle pressure depend on
Temperature, graph given in AMM
How long is the service life of bottle discharge cartridge (squib)
5 years, max 10
What is done to protect extinguishing bottles against HIRF
Screening of cables, HIRF filters, using faraday cage, ensuring bonding of components
What is the metered extinguishing system in the cargo hold
Metered bottles discharge at a slow controlled rate meaning fire will be extinguished for 180 minutes
How does the extinguisher in the lavatories bin work
Has solder that melts at 76°C which breaks seal and agent is released inside the bin
