Chapter 15: Fire Protection Flashcards

1
Q

hot zone and cold zone section in engine

A

hot zone: combustor to exhaust
cold zone: from fan to compressor

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2
Q

why are the zones ventilated?

A

prevent accumulation of flammable vapours (fuel)

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3
Q

how can the zones be isolated?

A

fireproof bulkhead / firewall

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4
Q

purpose of engine ventilation

A

purge any flammable vapour from engine

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5
Q

why must the airflow vent be kept minimal?

A

1) minimise powerplant drag
2) correct proportion of air for fire extinguisher (agent wont leak out)
3) minimise intensity of fire outbreak (less air fed to fire)

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6
Q

what does the fire detection unit do?

A

uses 2 identical loops to find FIRE and FAULT to send signals to flight warning computer to EICAS

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7
Q

what is classified as real fire?

A

when both loop A and B detects fire

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8
Q

3 types of fire detection system

A

1) thermocouple
2) thermal switch
3) continuous loop

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9
Q

what is a thermocouple system?

A

2 dissimilar metal (Chromel & Alumel) makes up hot & cold junction, when difference in temp between hot and cold junction, current is created

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10
Q

how does a thermal switch system work?

A

heat present > case becomes longer causing 2 contacts inside to be drawn tgt > loop closed causing alarm to sound

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11
Q

3 common types of continuous loop system

A

1) kidde
2) fenwal
3) pneumatic pressure detector

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12
Q

what does a fenwal system consist of?

A

slender Inconel tube filled with thermally sensitive eutectic salt and nickel center wire conductor

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13
Q

how does fenwal system work?

A

eutectic salt melt from high temp > resistance drop means current flow to provide signal

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14
Q

how does a kidde system work?

A

resistance of thermistor material decreases rapidly from high temp > change of resistance is sensed by EEC

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15
Q

how does a pressure type sensor work?

A

pressure of gas inside increases with heat > actuates diaphragm switch in responder > closes circuit and send signal

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16
Q

how many fire bottles are for each engine?

A

2

17
Q

where are the fire bottles located for the engine?

A

pylon

18
Q

what will be cut off by pressing the fire push button?

A

fuel supply
hydraulic supply
electrical power
bleed supply

19
Q

commonly used agent for fire extinguishing

A

1) carbon dioxide
2) methyl bromide
3) halon 1301

20
Q

what will happen when engine is caught on fire for engine fire warning?

A

1) red light on fire handle will light up
2) loud aural warning

21
Q

steps for dealing with engine fire warning

A

1) retard engine throttle which is on fire
2) shut down engine
3) press fire push button
4) press fire agent button

22
Q

what are the tests on the cartridge units?

A

checking insulation resistance, continuity and resistance of fuse/wire