Fire prevention – bays or zones:

To prevent the spread of a fire within an aircraft/engine nacelle, it is divided up into sections or zones, each being separated by a fireproof bulkhead. These are made of titanium or stainless steel and prevent the fire from spreading into adjacent areas.
The engine nacelle is split into two sections (UK).

Zone 1. The cool section contains the:

• Fan
• Compressor
• Fuel Control
• Air system supply
• Hydraulic pump
• AC generator
• Bleed valves and Variable Inlet Guide Vane (VIGV) systems

Zone 2. The hot section contains the:

• Fuel burners
• Combustion chamber
• Turbines LP & HP
• Exhaust

All fire zones are sealed from adjacent areas. Fire resistant rubber seals are fitted to the edges of all doors, panels and bulkhead fittings to prevent fire spreading. Each of the zones will be ventilated to prevent the build up gases or pressure and to cool the outer casing of the engine and accessories. Fire break in panels will be built in to allow the use of external fire extinguishers, these may also operate as blow out doors to prevent pressure build up in the zone.