Engine Fire Protection Systems

Question 1

Where are the fire switches normally installed?

Answer 1

Center overhead panel or center console

Question 2

What are the main categories of engine fire protection systems?

Answer 2

Spot Detection, Continuous Loop, Flame Detectors

Question 3

Name examples of spot-detection type systems.

Answer 3

Thermal Switch and Thermocouple

Question 4

Name examples of continuous-loop detection systems.

Answer 4

Fenwal, Kidde, Pneumatic

Question 5

When using a thermocouple type fire detector system, what happens if the engine overheats slowly?

Answer 5

Will not give a warning

Question 6

How many thermocouples are required for engine fire detection?

Answer 6

Depends on the size of the fire zone and the total circuit resistance

Question 7

Describe the operation of the Kidde continuous loop fire detection system.

Answer 7

Uses two wires embedded in a ceramic insulator whose conductivity increases as it gets hot completing the circuit and lighting the light

Question 8

Where does a thermocouple fire detector system get its electrical power to operate?

Answer 8

The thermocouple produces power to close a relay, and power from the aircraft electrical system flows through the relay to the warning light.

Question 9

Describe a thermal switch fire detection system.

Answer 9

Thermal switch systems have one or more lights that are energized by the aircraft electrical system when a heat sensitive thermal switch closes the circuit at a specific temperature

Question 10

How are thermal switches electrically connected in the circuit?

Answer 10

Connected in parallel with each other and in series with the warning light

Question 11

What is the most common cause of a false fire warning in a continuous loop detector system?

Answer 11

Dents, kinks, or crushed sensing elements

Question 12

Will a continuous loop fire detector still indicate the presence of a fire if the element is broken in two?

Answer 12

Yes

Question 13

What two methods are used to discharge fire extinguishing agents?

Answer 13

Mechanical and Electrical

Question 14

What method is used to release the fire extinguishing agent in a typical turbine engine fire protection system?

Answer 14

Discharge valves that are operated by electrically discharged explosive cartridges, (squibs)

Question 15

What method is used to determine proper fire extinguisher container pressure?

Answer 15

Container gauge

Question 16

What is the color marking used to identify fire extinguishing lines?

Answer 16

Brown tag with a row of black diamonds

Question 17

What method other than the pressure gauge is used to indicate low agent pressure in a container?

Answer 17

Low-pressure warning light in the cockpit

Question 18

What is the purpose of the yellow and red discharge plugs (disks) in a turbine engine fire extinguishing system?

Answer 18

Yellow plug indicates a pilot-initiated discharge. Red plug indicates a thermal activated discharge.

Question 19

What are two methods commonly used to distribute the fire extinguishing agent to the engine?

Answer 19

Perforated tube or discharge nozzles

Question 20

How does the fire extinguishing agent put out the fire?

Answer 20

Dilutes the atmosphere so that it will not support combustion

Question 21

What does HRD stand for?

Answer 21

High Rate of Discharge

Question 22

How is the fire extinguishing agent distributed from a HRD system?

Answer 22

Delivered from open-end tubes

Question 23

How long does it take to discharge the extinguishing agent in a HRD system?

Answer 23

1 to 2 seconds

Question 24

Which type of fire detection system gives a more complete coverage to a fire hazard?

Answer 24

Continuous-loop system

Question 25

What happens to the resistance of a thermocouple if you make it shorter?

Answer 25

The resistance changes

Question 26

What can you do instead of shortening a thermal couple?

Answer 26

Wrap it in loops and zip tie it

Question 27

What happens when you cut the leads of a cylinder head temp probe shorter?

Answer 27

The resistance changes