Airframe Fire Protection Systems Flashcards

Questions and Answers

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

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

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

Parallel.

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

In parallel between two complete loops of wire.

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

Thermocouple systems are sensitive to the rate of temperature change, whereas thermal switch systems respond to a specific temperature value. Signup and view all the answers

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

A Kidde system has an Inconel tube containing one or more wires embedded in a ceramic core whose resistance changes with temperature. Signup and view all the answers

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

A stainless steel tube contains 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. Signup and view all the answers

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

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

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

By actuating a test switch. Signup and view all the answers

Name two types of smoke detection systems used in aircraft.

Light refraction (photoelectric) types and ionization types. Signup and view all the answers

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

In an aircraft cockpit or cabin. Signup and view all the answers

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

The tan spot on the detector turns gray or black. Signup and view all the answers

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

False fire warnings caused by short circuits. Signup and view all the answers

How is a Freon container checked for proper pressure?

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

Name the two basic types of fire extinguishing systems.

The conventional system and the high-rate discharge system. Signup and view all the answers

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

Carbon dioxide (CO2). Signup and view all the answers

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

Halon (Halogenated hydrocarbon type agents), also known as Freon. Signup and view all the answers

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

A thermal fuse (or blowout disk) will release the agent if the bottle temperature exceeds a certain limit, which blows out a red indicator disk. Signup and view all the answers

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

The system has been discharged normally. Signup and view all the answers

Describe the mechanism by which a Freon bottle is discharged.

An electrical signal fires an explosive squib, which ruptures a frangible disk. Signup and view all the answers

How is the service life of a discharge cartridge calculated?

From the date stamped on the cartridge by the manufacturer. Signup and view all the answers

Does a thermocouple fire detection system warn the pilot of a general overheat condition?

False Signup and view all the answers

Does a thermal switch fire detection warn the pilot of a general overheat condition?

False Signup and view all the answers

What type of fire extinguishing agent is best for both cabin fires and engine fires?

Halon 1301. Signup and view all the answers

What is a major disadvantage of 'CB' fire extinguishing agent for extinguishing aircraft fires?

It is corrosive to aluminum and magnesium. Signup and view all the answers

Why is carbon tetrachloride not recommended as a fire extinguishing agent?

Carbon tetrachloride produces phosgene, a deadly gas, when it is exposed to flames. Signup and view all the answers

Study Notes

Fire Detection Systems

Thermal switch systems consist of temperature-sensitive switches that complete circuits upon reaching specific temperatures, triggering warnings.
Thermal switches are wired in parallel, ensuring that if one switch is activated, others can still function.
In a double-loop Fenwal fire detection system, detector units are wired in parallel across two complete loops of wire.
Thermocouple systems are responsive to the rate of temperature change, unlike thermal switch systems, which react to absolute temperature values.
The Kidde continuous loop fire detection system comprises an Inconel tube containing wires embedded in a ceramic core, where resistance changes with temperature.

Fire Detection Technology

The Lindberg fire detection system uses a stainless steel tube filled with inert gas. Heat release raises pressure, activating a pressure switch.
Photoelectric smoke detectors work by using light refraction caused by smoke particles, triggering an electric signal to sound an alarm.
Testing a photoelectric smoke detector can be done by actuating a test switch.
Two common smoke detection systems in aircraft are light refraction (photoelectric) and ionization types.

Carbon Monoxide Detection

Carbon monoxide detectors are typically installed in aircraft cockpits or cabins.
Detection of carbon monoxide is indicated by a change in color of a tan spot to gray or black on the detector.

Fire Warning Systems

Kinks and sharp bends in fire warning system sensing elements can cause false fire warnings due to short circuits.
Freon containers are checked for proper pressure using a chart that correlates gauge readings with ambient temperatures.

Fire Extinguishment Systems

There are two basic types of fire extinguishing systems: conventional systems and high-rate discharge systems.
The most common agent in conventional fire extinguishing systems is carbon dioxide (CO2), while high-rate discharge systems typically use Halon (halogenated hydrocarbon agents).
Freon bottles are equipped with thermal fuses (or blowout disks) that release the agent if temperatures exceed safe limits, indicated by a blown red disk.
The absence of a yellow disk in a fire extinguishing system signifies that the system has been discharged normally.

Discharge Mechanisms

Freon bottles are discharged via an electrical signal that activates an explosive squib to rupture a frangible disk.
The service life of a discharge cartridge is determined from the manufacturing date stamped on it.

Additional Information

Thermocouple fire detection systems do not warn pilots of general overheat conditions, as they are designed to detect only fires.
Thermal switch fire detection systems also do not provide warnings for general overheat conditions.
Halon 1301 is the preferred extinguishing agent for cabin and engine fires.
A significant drawback of "CB" extinguishing agents is their corrosive nature towards aluminum and magnesium components.
Carbon tetrachloride is not advisable as a fire extinguishing agent because it generates phosgene, a toxic gas, when exposed to flames.

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Description

Test your knowledge about fire protection systems in airframes with these flashcards. Learn about thermal switches, their wiring configurations, and the components of fire detection systems. A great way to prepare for exams in aviation safety.