Questions – Aircraft Engine Fire Protection Systems

1. Which of the following fire detectors are commonly used in the power section of an engine nacelle?

1. CO detectors.
2. Smoke detectors.
3. Rate-of-temperature-rise detectors.

2. What is the function of a fire detection system?

1. To discharge the powerplant fire-extinguishing system at the origin of the fire.
2. To activate a warning device in the event of a powerplant fire.
3. To identify the location of a powerplant fire.

3. (Refer to figure 1) Determine the fire-extinguisher container pressure limits when the temperature is 75⁰F.

1. 326 minimum and 415 maximum.
2. 330 minimum and 419 maximum.
3. 338 minimum and 424 maximum.

4. How are most aircraft turbine engine fire-extinguishing systems activated?

1. Electrically discharged cartridges.
2. Manual remote control valve.
3. Pushrod assembly.

5. How does carbon dioxide (C0₂) extinguish an aircraft engine fire?

1. Contact with the air converts the liquid into snow and gas which smothers the flame.
2. By lowering the temperature to a point where combustion will not take place.
3. The high pressure spray lowers the temperature and blows out the fire.

6. What retains the nitrogen charge and fire-extinguishing agent in a high rate of discharge (HRD) container?

1. Breakable disk and fusible disk.
2. Pressure switch and check tee valve.
3. Pressure gauge and cartridge.

7. A continuous-loop fire detector is what type of detector?

1. Spot detector.
2. Overheat detector.
3. Rate-of-temperature-rise detector.

8. What is the operating principle of the spot detector sensor in a fire detection system?

1. Resistant core material that prevents current flow at normal temperatures.
2. A conventional thermocouple that produces a current flow.
3. A bimetallic thermoswitch that closes when heated to a high temperature.

9. How is the fire-extinguishing agent distributed in the engine section?

1. Spray nozzles and fluid pumps.
2. Nitrogen pressure and slinger rings.
3. Spray nozzles and perforated tubing.

10. Which of the following is the safest fire-extinguishing agent to use from a standpoint of toxicity and corrosion hazards?

1. Dibromodifluoromethane (Halon 1202).
2. Bromochlorodifluoromethane (Halon 1211).
3. Bromotrifluoromethane (Halon 1301).

11. Which of the following is NOT used to detect fires in reciprocating engine nacelles?

1. Smoke detectors.
2. Rate-of-temperature-rise detectors.
3. Flame detectors.

12. What is the principle of operation of the continuous-loop fire detector system sensor?

1. Fuse material which melts at high temperatures.
2. Core resistance material which prevents current flow at normal temperatures.
3. A bimetallic thermoswitch which closes when heated to a high temperature.

13. The most satisfactory extinguishing agent for a carburetor or intake fire is

1. carbon dioxide.
2. dry chemical.
3. methyl bromide.

14. The explosive cartridge in the discharge valve of a fire extinguisher container is

1. a life-dated unit.
2. not a life-dated unit.
3. mechanically fired.

15. Why does one type of Fenwal fire detection system use spot detectors wired in parallel between two separate circuits?

1. To provide an installation that is equal to two separate systems: a primary system and a secondary, or back-up system.
2. So that a double fault may exist in the system without sounding a false alarm.
3. So that a single fault may exist in the system without sounding a false alarm.

16. Which of the following fire detection systems measures temperature rise compared to a reference temperature?

1. Thermocouple.
2. Thermal switch.
3. Lindberg continuous element.

17. The pulling out (or down) of an illuminated fire handle in a typical large jet aircraft fire protection system commonly accomplishes what events?

1. Closes all firewall shutoff valves, disconnects the generator, and discharges a fire bottle.
2. Closes fuel shutoff, closes hydraulic shutoff, disconnects the generator field, and arms the fire extinguishing system.
3. Closes fuel shutoff, closes hydraulic shutoff, closes the oxygen shutoff, disconnects the generator field, and arms the fire-extinguishing system.

18. A fire detection system operates on the principle of a buildup of gas pressure within a tube proportional to temperature. Which of the following systems does this statement define?

1. Kidde continuous-loop system.
2. Lindberg continuous-element system.
3. Thermal switch system.

19. The fire detection system that uses a single wire surrounded by a continuous string of ceramic beads in a tube is the

1. Fenwal system.
2. Kidde system.
3. thermocouple system.

20. The fire detection system that uses two wires imbedded in a ceramic core within a tube is the

1. Fenwal system.
2. Lindberg system.
3. Kidde system.

21. A fuel or oil fire is defined as a

1. class B fire.
2. class A fire.
3. class C fire.

22. A fire detection system that operates on the rate-of temperature rise is a

1. continuous-loop system.
2. thermocouple system.
3. thermal switch system.

23. A fire involving energized electrical equipment is defined as a

1. class B fire.
2. class D fire.
3. class C fire.

24. Two continuous-loop fire detection systems that will not test due to a broken detector element are the

1. Kidde system and the Lindberg system.
2. Kidde system and the Fenwal system.
3. thermocouple system and the Lindberg system.

25. In a fixed fire-extinguishing system, there are two small lines running from the system and exiting overboard. These line exit ports are covered with a blowout type indicator disc. Which of the following statements is true?

1. When the red indicator disc is missing, it indicates the fire-extinguishing system has been normally discharged.
2. When the yellow indicator disc is missing, it indicates the fire-extinguishing system has been normally discharged.
3. When the green indicator disc is missing, it indicates the fire-extinguishing system has had a thermal discharge.

26. The most satisfactory extinguishing agent for an electrical fire is

1. carbon tetrachloride.
2. carbon dioxide.
3. methyl bromide.

27. Which of the following fire detection systems will detect a fire when an element is inoperative but will not test when the test circuit is energized?

1. The Kidde system and the thermocouple system.
2. The Kidde system and the Fenwal system.
3. The thermocouple system and the Lindberg system.

28. Which of the following fire detection systems uses heat in the normal testing of the system?

1. The thermocouple system and the Lindberg system.
2. The Kidde system and the Fenwal system.
3. The thermocouple system and the Fenwal system.

29. After a fire is extinguished, or overheat condition removed in aircraft equipped with a Systron-Donner fire detector, the detection system

1. must be manually reset.
2. automatically resets.
3. sensing component must be replaced.

30. The use of water on class D fires

1. is most effective if sprayed in a fine mist.
2. will cause the fire to burn more violently and can cause explosions.
3. has no effect.

31. For fire detection and extinguishing purposes, aircraft powerplant areas are divided into fire zones based on

1. hot and cold sections of the engine.
2. the volume and smoothness of the airflow through engine compartments.
3. engine type and size.

32. (Refer to figure 2) What are the fire-extinguisher container pressure limits when the temperature is 50 ⁰F?

1. 425 – 575 PSIG
2. 435 – 605 PSIG
3. 475 – 625 PSIG.

Answer key