Engine Fire Protection Systems

Question 1

What types of fire detector systems are used for engine fire detection?

Answer 1

Overheat, rate of rise and flame detectors

Question 2

How does a thermal switch protection system operate?

Answer 2

When heated past a predetermined temperature, the switch activates the warning devices in the cockpit

Question 3

How many thermal switches are needed in a thermal switch protection system?

Answer 3

At least one

Question 4

What kind of fire detection system allows more complete coverage than a spot type system?

Answer 4

A continuous loop system

Question 5

What happens in an engine equipped with a thermocouple fire warning system overheats slowly?

Answer 5

Nothing because a fast rate or rapid heat heaters required for this type of fire system to operate

Question 6

What electrical power is required for a thermocouple fire protection system to operate

Answer 6

Both the thermocouple power and aircraft electrical system are required

Question 7

What is the likely cause of a false fire warning?

Answer 7

Fire sensing loop is bent or kinked

Question 8

What are fire extinguishing systems design to do?

Answer 8

The dilute the oxygen around the engine to a point that does not allow combustion or reduces temperatures below the ignition point.

Question 9

Describe how a Kiddle and Fenwal continuous loop fire protection system functions.

Answer 9

Kiddle - Inconel tube with two connectors, one grounded the other is a positive lead, when a fire or overheat occurs the resistance of the thermistor drops and allows current to flow between the wires to activate the alarm.

Fenwal - sensing element with ceramic beads, when a fire or overheat occurs the core resistance drops allowing current to flow between the center electrode and the ground to activate the alarm.

Question 10

What elements must be present for a fire to occur?

Answer 10

An ignition source, fuel and oxygen

Question 11

What group of fire extinguishing agents are no longer manufactured after 1995?

Answer 11

Halons (or Freon or Chlorofluorocarbons)

Question 12

How are fire extinguishing agents distributed?

Answer 12

Through perforated tubing and/or discharge nozzles

Question 13

What is the purpose of the discharge cartridge and how is it activated?

Answer 13

The discharge cartridge, or squib, which is electrically ignited fires a projectile into the frangible disk, thereby releasing fire extinguisher agent

Question 14

How is a fire extinguisher system with a high rate of discharge classified?

Answer 14

As a HRD fire extinguisher system

Question 15

How is an HRD fire extinguisher agent distributed?

Answer 15

Through open end tubes

Question 16

How long does it take to discharge an HRD agent?

Answer 16

1 to 2 seconds

Question 17

How is the fire extinguishing agent and HRD system distributed?

Answer 17

Through a series of high-pressure tubes

Question 18

What do the red and yellow desk at a fire extinguisher in system indicate

Answer 18

Yellow indicates normal discharge and red indicates thermal discharge

Question 19

What is the purpose of the pressure gauge in a fire extinguishing system?

Answer 19

Indicates pressure inside the container. To check if the pressures within limits, a pressure temperature chart is used.

Question 20

What is the proper method for determining the fire extinguisher container pressure?

Answer 20

Container gauge pressure used with pressure temperature curve/chart will indicate if the pressure is within limits.