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23 Cards in this Set
- Front
- Back
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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.
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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.
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How is a thermocouple–type fire detection system checked for operation?
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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.
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Does a break in a continuous–loop fire detection system keep the system from detecting a fire?
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No, the unit will show a fault when it is tested, but it will still warn of a fire.
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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. |
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What are the two most commonly used fire extinguishing agents used for engine fires?
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Halogenated hydrocarbon, such as Halon 1301, and carbon dioxide.
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What extinguishing agent is used in the high–rate–discharge fire extinguishing systems installed in most turbojet engine installations?
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Halon 1301.
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What happens when the pilot pulls the fire–pull T–handle in the cockpit of a jet transport airplane?
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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.
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How can a mechanic determine the state of charge of the HRD bottles of fire extinguishing agent?
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A pressure gage on the bottle shows the pressure of the contents of the bottle.
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What method is used to discharge an HRD bottle in a turbine engine installation?
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An electrically ignited powder charge blows a knife through the seal on the bottle and discharges the contents.
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Which type of fire detection system operates on the rate of temperature rise?
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The thermocouple system.
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What is indicated if the yellow blow–out plug of the fire extinguisher system on the side of an engine nacelle is blown out?
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The built–in fire extinguishing system has been discharged by normal operation.
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What is indicated if the red blow–out plug of the fire extinguisher system on the side of an engine nacelle is blown out?
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The built–in fire extinguishing system has been discharged by a high temperature condition.
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How is a pressure–type continuous–element fire detector system checked for operation?
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Low–voltage alternating current is sent through the sheath of the detector element. This heats the element, and it releases enough gas to close the diaphragm switch.
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What are four types of engine fire detection systems?
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Thermoswitch
Thermocouple Thermistor–type continuous–loop Pneumatic–type continuous–loop |
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Why must the reference junction in a thermocouple fire detection system be thermally insulated?
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So the temp will not rise as quickly as that of the measuring junctions if a fire should occur
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What would likely cause a false fire alarm in a thermistor–type continuous–loop system?
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A kinked or pinched continuous–loop element
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If there is a break in a single–wire continuous–loop fire detector element, and the system tests bad, will it indicate the presence of a fire?
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Yes, even though it tests bad, it will still indicate the presence of a fire
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How is a pneumatic–type continuous–loop fire detection system checked for operation?
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When the test switch is closed, low–voltage AC flows through the tube that encloses the sensitive element. This current heats the element enough for it to release sufficient gas to activate the alarm switch
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What maintenance is allowed of a continuous–loop fire detection system?
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Inspect and replace as needed the continuous–loop element, the controller, and the fire warning bell and/ or light
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What is used as a fire extinguishing agent in some older aircraft?
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Carbon dioxide (co2)
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What precaution must be taken when checking the electrical circuit for igniting the powder charge in the valve of a high–rate discharge bottle?
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The current used to check the integrity of the circuit must not be high enough to ignite the powder charge
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What color and marking is used to identify the fluid lines that carry the fire extinguishing agent in an aircraft?
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Brown tape with a series of diamonds on it |
