The fire protection system (Figure 1-1 and Figure 1-2) serves
three major functions: fire detection, overheat detection, and
fuel inerting. Elements within the engine nacelle sense an
engine fire. Separate elements in the Environmental Control
System (ECS) bay, Emergency Power Unit (EPU) bay, and
next to the bleed air ducts sense an overheat state in these
areas. Warning lights provide a display of a detected fire or
overheat state. The fuel inerting subsystem, when started,
stops the ignition of fuel vapor by supplying halon to the fuel
tanks.