Airframe Chapter 16

Question 1

Briefly describe the components of a thermal switch fire detection system.

Answer 1

Temperature sensitive switches that complete a circuit at a specific temperature and trigger a warning.

Question 2

Are thermal switches wired in series or in parallel with each other?

Answer 2

Parallel

Question 3

How are the detector units in a double loop Fenwal system wired?

Answer 3

In parallel between two complete loops of wiring.

Question 4

In what way is a thermocouple fire warning system different from a thermal switch system?

Answer 4

Thermocouple systems are sensitive to the rate of temperature change, whereas thermal switch systems respond to a specific temperature value.

Question 5

Briefly describe the components of a Kidde continuos loop fire detection system.

Answer 5

A Kidde system has an Inconel tube containing one or more wires embedded in a ceramic core whose resistance changes with temperature.

Question 6

Briefly describe the components and operation of a Lindberg fire detection system.

Answer 6

A stainless steel tube containing an inert gas and a discrete material that absorbs some of the gas. When the tube heats up, some gas is released, raising the pressure in the tube, which activates a pressure switch.

Question 7

Describe the process or mechanism by which a photoelectric smoke detector generates a warning of a possible fire.

Answer 7

Smoke particles refract light in the detector unit causing the photoelectric cell to conduct electricity and trigger the alarm.

Question 8

How can the operation of a photoelectric smoke detector be tested?

Answer 8

By actuating a test switch.

Question 9

Name two types of smoke detection systems used in aircraft.

Answer 9

Light refraction (photoelectric) types and ionization types.

Question 10

What are the usual locations where a carbon monoxide detector would be installed?

Answer 10

In an aircraft cockpit or cabin.

Question 11

How does a carbon monoxide detector indicate the presence of this deadly gas?

Answer 11

The tan spot on the detector turns gray or black.

Question 12

What are the possible effects of kinks and sharp bends in the sensing element of a fire warning system?

Answer 12

False fire warnings caused by short circuits.

Question 13

How is a Freon container checked for proper pressure?

Answer 13

A chart must be used to determine the maximum and minimum gauge pressure readings based on the ambient temperature.

Question 14

Name the two basic types of fire extinguishing systems.

Answer 14

The conventional system and the high rate discharge system.

Question 15

Name the extinguishing agent most commonly used by conventional fire extinguishing systems.

Answer 15

Carbon dioxide.

Question 16

Name the extinguishing agent most commonly used by high rate discharge fire extinguishing systems.

Answer 16

Halon (Halogenated hydrocarbon type agents), also known as Freon.

Question 17

How are Freon bottles protected from excessively high temperatures and how can you tell that this has occurred?

Answer 17

A thermal fuse (or blowout disk) will release the agent if the bottle temperature exceeds a certain limit. It’s blows out a red indicator disk.

Question 18

What condition is indicated if the yellow disk is missing in a fire extinguishing system?

Answer 18

The system has been discharged normally.

Question 19

Describe the mechanism by which a Freon bottle is discharged.

Answer 19

An electrical signal fires an explosive squib, which ruptures a frangible disk.

Question 20

How is the service life of a discharge cartridge calculated?

Answer 20

From the date stamped on the cartridge by the manufacturer.