200 fire and overheat protection Flashcards
What are the four areas with fire and overheat protection?
Engine
Jet pipes and pylons
APU
Main landing gear
What two areas have smoke detection systems?
Cargo bay
Lavatory
What areas of the engine have fire and overheat protection?
Fire and overheat protection are provided in the jet pipe, nacelle, and pylon areas. These are divided into two zones, the engine area which is the core of the engine and second is the jet area which is the jet pipe and pylon
This fire extinguishing provided in both the engine and jet zones of the engine?
Fire extinguishing is provided in the engine zone only. Detection is provided in the Jet and pylon zone.
What ducting is contained in the jet zone?
10th stage and 14th stage bleed air ducting are contained in this zone.
What in the engine actually detects the fire or overheat condition?
There are two detection loops labeled a and B, Which are connected to a control unit. As there is an increase in temperature the electrical resistance of the insulator decreases with an increase in temperature to a trip point at which there’ll be a fire or overheat indication generated.
How are the detection loops arranged in the engine zone?
The detection loops are located in the aft engine core and the side of the cowl panel that is near the fuselage
How are the groups arranged in the jet zone?
The loops are around the jet pipe and it runs along the 10th and 14th stage bleed air ducting in the pylon areas
What are the two benefits of the dual loop detection systems?
Minimize false fire warnings. This is because both loops must sense for fire or overheat condition before a fire is detected.
The aircraft can be dispatched with a loop that is in operative and still provide fire and overheat protection.
Explain the operation of the fire detection control unit.
This unit monitors the electrical resistance of the loops. Both loops must sense the same decrease in electrical resistance at the same time for the fire detection control unit to send a signal to the EICAS.
What do the fire extinguisher bottles contain?
The bottles contained Halon and are pressurized with nitrogen
Where are the engine fire extinguishers located?
The extinguishers are located in the aft equipment bay below the APU enclosure
Will the left engine fire bottle only discharge into the left engine?
No, both bottles can be discharged into one engine. This is determined by which fire switch is pressed.
What is the purpose of the FIRE DETECTION Control Panel?
To select a single loop if one has failed so the aircraft can be dispatched. The panel can also be used to test the fire and over heat detection system.
What happens when the LH or RH FIRE PUSH switch light are pressed?
- Fuel feed SOV is closed
- Bleed air SOV is closed
- Hydraulic SOV is closed
- Engine driven generator is taken off-line
- Both fire extinguisher bottle squibs are armed, both BOTTLE ARMED PUSH TO DISCH switch lights illuminate.