Engine bay fire detection
Two electrically separate fire wire loops, co-sited in a performed steel conduct, are located in the nacelle doors and around the engine, in normal operation both loops are in a circuit and both must detect a fire signal a warning. If only one loop is unserviceable, the good loop may be selected for single channel operation.
Ultra violet flame detection
Three dual circuit detector assemblies were strategically placed within the nacelle to detect flame break-out from any point of combustion chamber circumference. As their tile suggests, they respond to UV light. Once again, both circuits must detect to signal a warning and, when necessary, signal circuit operation may be selected. There were problems with this detector during service, it was reliable and was replace by some additional lengths of fire wire.
Engine internal overheat
Thermal switches are located adjacent to bearings 2, 3, 4 and 5; any one will illuminate its ‘ENGINE OVERHEAT’ warning. Prompting engine shut-down. Turbine cooling air temperature is sensed and presented on a gauge at the flight engineer’s panel; a 640C thermal switch brings on the ‘ENGINE OVERHEAT’ warning.
This comprises a single fire wall loop in each nacelle adjacent to pressurisation bleed-air equipment and two thermal switches in a wing equipment bay above the engine. Any one of the three elements, sensing a hot air leak, will trigger a ‘NACELLE/WING OVERHEAT’ warning.
Engine fire protection
One fire extinguisher bottle is located in a wing equipment bay above each engine. Each bottle has two firing heads and is capable of discharging into its own, or the adjacent, engine bay. In the event of an engine fire, first the engine is shut down, then the engine’s own bottle discharged and if the fire still persists the adjacent bottle is used.
Ten smoke detectors are strategically positioned within the fuselage adjacent to equipment zones and baggage holds. During Concorde’s service life, toilet smoke detectors became mandatory and were fitted to all Concordes in 1987