FIRE PROTECTION SYSTEMS

A complete fire warning system consists of a detection system, an extinguisher system and a method of detecting that the fire is out. There are specified areas that only have detection systems, these are parts of engine bays and hot air ducts.

Detectors are mounted within the zones next to the components more prone to a fire or overheat condition, the choice of detection system, fire or overheat, depends on the contents of the zone.

Zone 1 (UK) contains the fuel control system, in this zone a fire could develop therefore the detection system used is a FIRE WARNING SYSTEM.

Zone 2 (UK) includes the rear section of the engine and the jet pipe, this zone is identified as an overheat area only and will have an OVERHEAT WARNING SYSTEM.

A fire or heat detection system should:

• Give a rapid indication of condition with an audio warning for fire (bell), the audio should have a cancellation facility and should be auto resetting.
• Provide location information concerning the fire or overheat condition.
• Have a warning system that will continue during fire.
• Continue to operate where the fire is located.
• Provide an indication that the fire is out or that the overheat condition no longer exists.
• Include an "in flight" test facility.
• Not automatically shut down the main power unit or operate the engine fire extinguishers, it may however shut down the APU usually only when on the ground.
• Not produce false indication in event of failures or fault conditions.