Airframe Systems & Components: Fire Protection Systems 🔊 Flashcards
In what area of an aircraft would you find carbon monoxide detectors?
Cabins and cockpits
What color does a CO detector change to when carbon monoxide fumes are present?
Yellow silica turns a shade of green when contaminated. Other types turn from tan to grey or black.
What are two types of smoke detectors?
Photoelectric and visual
Where are smoke detectors used in the aircraft?
In cargo and baggage compartments and the lavatory
How are thermal switches wired in thermal switch fire detection systems?
Switches are wired in parallel with each other and series with the warning lights
Describe the operating principle of a thermal switch fire detection system.
They consist of one or more lights which are energized by aircraft power when connected to the circuit by a thermal switch. Thermal switches are heat sensitive units that complete the circuit at a certain temperature.
Describe the operating principle of a continuous loop fire detection system.
They consist of one or more wires embedded in a special ceramic core inside of a conductive tube. In case of fire or overheating, the core resistance drops allowing current to flow between the signal wire and conductive tube, lighting a warning light.
How does a thermocouple fire detection system differ from the thermal switch system?
Thermocouple depends upon the rate of temperature rise and will not give a warning when the engine overheats slowly or a short circuit develops.
What are two types of fire extinguisher systems?
High rate of discharge (HRD) system uses Halon and is effective on all fire classes. Conventional fire systems use carbon dioxide and are effective on Class B and C fires.
What type of extinguisher agent is usually found in an HRD system?
Usually halogenated hydrocarbons (Halons) boosted by high pressure dry nitrogen. Most commonly Halon 1301 (Freon 13).
What type of extinguishing agent is usually associated with a conventional type extinguishing system?
It usually contains CO2 but may use any other adequate agent.
What is the purpose of the yellow disk in a CO2 fire extinguishing system?
It is a discharge indicator that indicates which bank of bottles has been emptied by normal discharge.
How can you determine the charge of a CO2 extinguisher?
By weighing it
In a turbine engine Freon (Halon) fire extinguishing system, how are bottles discharged?
An explosive discharge cartridge (squib) which is detonated electrically, breaking a frangible disk.
How is a Halon fire extinguishing system protected from temperature rises more than set limits?
It is equipped with a thermal fuse that melts at high temperature conditions and will blow a red discharge indicator disk.
How does ambient temperature affect the pressure reading on a fire extinguisher?
Low temperatures decrease the pressure, high temperatures increase the pressure.
What type of extinguisher is recommended for brake fires?
A dry powder extinguisher.
How can you determine the service life of a fire extinguisher discharge cartridge?
The manufacturer’s date stamped on the cartridge
What type of hand held fire extinguishers are available for extinguishing interior aircraft fires?
The three most common for a Class A fire are water, carbon dioxide (CO2), and dry chemical extinguishing agents.
What type of fire detection system gives a more complete coverage of a fire hazard?
A continuous-loop detector system.
Name the different classes of fires.
Class A: solid combustible materials, Class B: combustible liquids, Class C: electrical, Class D: metal.
A - ashes
B - boil
C - circuit
D - death metal
How does a photoelectric smoke detector work?
Smoke particles block the photoelectric receptor from sensing light.
How would you determine when the next hydrostatic test is due on a portable fire bottle?
Look at the label for the DOT information. It will be five years from the last test date.
