ENGINE FIRE PROTECTION SYSTEMS Flashcards
What types of fire detectors are used for engine fire protection systems?
They are overheat detectors, rate-of-temperature-rise detectors, and flame detectors
When using a thermocouple type fire detector system, what happens if the engine overheats slowly?
A thermocouple depends on the rate of temperature rise and will not give a warning if the engine
slowly overheats or a short circuit develops.
Describe the operation of a Kidde continuous loop fire detector system
The Kidde continuous loop system has two wires embedded in a special ceramic core within an
inconel tube. One wire acts as an internal ground and the other wire is a hot lead that provides a
current when the ceramic core material changes its resistance with a rise in temperature.
Where does a thermocouple fire detector system get its electrical power to operate?
The thermocouple produces power to close a relay, and power from the aircraft electrical
system flows through the relay to the warning light.
Describe a thermal switch fire detector system?
Thermal switch systems have one or more lights that are energized by the aircraft’s electrical
system when a heat-sensitive thermal switch closes the circuit at a specific temperature.
How are thermal switches electrically connected in the circuit?
Thermal switches are connected in parallel with each other but in series with the warning light.
A temperature rise in any one section of the circuit will cause a thermal switch to close and
complete the circuit to indicate a fire or overheat condition.
What is the most common cause of a false fire warning in a continuous loop detector system?
The most common cause of false warnings is dents, kinks, or crushed sensing element causing
an internal wire to shore to the ground wire or outer tubing.
What two methods are used to discharge fire extinguishing agents?
Mechanical and electrical
What method is used to release the fire extinguishing agent in a typical turbine engine fire protection
system?
One common method is to equip the fire extinguishing containers with discharge valves that are
operated by electrically discharged cartridges. The discharge plug is seated with a breakable
disk that is ruptured by the explosive cartridge, and the contents of the bottle are discharged
into the engine area.
What method is used to determine proper fire extinguisher container pressure?
Check the container gauge to determine if the pressure is between the prescribed minimum and
maximum limits.
What method other than the pressure gauge is used to indicate low agent pressure in a container?
Some aircraft are equipped with a low-pressure warning light in the cockpit.
What is the purpose of the yellow and the red discharge plugs in a turbine engine fire extinguishing system?
The yellow plug indicates pilot initiated discharge, and the red plug indicates thermal discharge.
What are two methods commonly used to distribute the fire extinguishing agent to the engine?
Many systems use perforated tubing or discharge nozzles to distribute the agent.
How does the fire extinguishing agent put out the fire?
It dilutes the atmosphere so that it will not support combustion.
What does the ―HRD‖ stand for in an HRD fire extinguishing system?
High rate of discharge
