Engine Fire Protection Systems Flashcards
Can a thermal switch-type fire detection system indicate a general overheat condition?
No, this is a spot-type fire detection system, and it cannot indicate an overheat condition.
Can a thermocouple-type fire detection system indicate a general overheat condition?
No, this is a rate-of-temperature-rise-type of system, and it cannot indicate a general overheat condition.
How is a thermocouple-type fire detection system checked for operation?
Current is sent through the heater in the thermal test unit. This heats the thermocouple, which produces enough current to close the sensitive relay. Current through the contacts of the sensitive relay closes the slave relay and turns on the fire warning light.
Does a break in a continuous-loop fire detection system keep the system from detecting a fire?
No, the unit will show a fault when it is tested, but it will still warn of a fire.
Does the pressure-type continuous-element fire detector system detect a general overheat condition, as well as a fire?
Yes, a high temperature on a small portion of the sensor or a lower temperature over the entire sensor will cause it to release enough gas to close the diaphragm switch and warn of a fire.
What are the two most commonly used fire extinguishing agents used for engine fires?
Halogenated hydrocarbons, such as Halon 1301, and carbon dioxide.
What extinguishing agent is used in the high-rate-discharge fire extinguishing systems installed in most turbojet engine installations?
Halon 1301.
What happens when the pilot pulls the fire-pull T-handle in the flight deck of a jet transport airplane?
The bottle discharge switch is uncovered and armed, the generator field relay is tripped, fuel is shut off to the engine, hydraulic fluid is shut off to the pump, the engine bleed air is shut off, and the hydraulic pump low-pressure lights are deactivated.
How can a mechanic determine the state of charge of the HRD bottles of fire extinguishing agent?
A pressure gauge on the bottle shows the pressure of the contents of the bottle.
What method is used to discharge an HRD bottle in a turbine engine installation?
An electrically ignited powder charge blows a knife through the seal on the bottle and discharges the contents.
Which type of fire detection system operates on the rate of temperature rise?
The thermocouple system.
What is indicated if the yellow blow-out plug of the fire extinguisher system on the side of an engine nacelle is blown out?
The built-in fire extinguishing system has been discharged by normal operation.
What is indicated if the red blow-out plug of the fire extinguisher system on the side of an engine nacelle is blown out?
The built-in fire extinguishing system has been discharged by a high temperature condition.
How is a pressure-type continuous-element fire detector system checked for operation?
Low-voltage alternating current is sent through the sheath of the detector element. This heats the ele-ment, and it releases enough gas to close the diaphragm switch.
