Fire Testing ISO 2685
Aircraft fire detection systems
The fire or jet of hot gas that leads to the temperature rise can easily burn through the wiring or the sensor. The system must be designed so that if this does occur, then the warning is not extinguished. Equally the system must be designed so that no warnings are given when there is no fire. Both these conditions are dangerous. The first because the crew may think that a fire has been extinguished, the second because a system which continually gives spurious warnings may be disregarded when a real fire occurs.
Fire testing ISO 2685
This is why fire testing ISO 2685 is so critical, testing of airborne equipment resistance to fire in designated zones ISO2685:1998 and aircraft interiors fire performance to FAA 14 CFR:Part 25. Fire testing of fuselage burnthrough resistance is very much after a crash has become inevitable and the fight for survival has begun. Seat covers flammability testing is also used to gauge surviveability once disaster has become inevitable and needs to be appropriately managed.
Once a fire warning is observed a formal drill is initiated by the crew to extinguish the fire. This will include shutting down the engine and isolating the fuel system at the engine fire-wall by closing a cock in the fuel system, and then discharging extinguisher fluid into the bay.
This is done by pressing a switch in the cockpit (often a switch built into the fire warning lamp) which fires a cartridge built into a bottle containing a fluid such as BromoChlorodiFluoromethane (BCF). This causes a spray of fluid to be directed into the engine bay. Usually the bottles are single shot. If, after discharging the bottle, the fire warning remains, the crew must decide if the warning is genuine. In a commercial aircraft this can be done by looking out of a window to see if flames can be seen in the engine nacelle, in a military aircraft by asking another aircraft to observe from behind. If a fire is confirmed then the aircraft must be landed as soon as possible, or abandoned.
Modern fluids have been developed, which do not contain environmentally harmful fluoro-carbon materials and are being introduced to meet mandatory regulations (Montreal Protocol).
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1992 Sea Ray 200BR
