How Do Fire Extinguishing & Detection Systems Work in Aircraft?

Fire extinguishing and detection systems in general aviation are paramount, mitigating and preventing fires from ensuing on aircraft and keeping passengers safe. Fire suppression systems can be divided into two subsystems, those of which are the fire detection system and the fire extinguishing system. Each system is equipped with unique features that are meant to protect certain aircraft structures and their components.

Work Of Fire Detection Systems in Aircraft

Aircraft equipment that incorporate fire detection systems include the engines, APUs, and lavorities, as well as the cargo, avionic, and IFE compartments. The fire detection systems installed on engines and APUs often include protective wirings that detect unintended temperature increases, and send electrical signals to the smoke detector computer. This computer informs pilots when such an occurrence is taking place. The cargo compartments are furnished with electronic detector boxes in the cargo ceiling. When there is smoke present, the detector senses the smoke density and informs the smoke detector computer to transmit this data to the cockpit. Lastly, the avionic and IFE compartments have similar smoke detectors that also send an electrical signal to the cockpit.

Applications Of Fire Extinguishing Systems in Aircraft

Meanwhile, the fire extinguishing system consists of halon (Bromotrifluoromethane), a nonconductive fire-extinguishing agent used in all aviation systems. However, halon is known to be hazardous for the environment and ozone layer. With this in mind, halon has been banned in aircraft systems since 1987. Since then, alternative agents are continuing to be studied worldwide, and so far, FE36 is the only alternative agent currently being used. As it is heavier than halon gas, it is predominantly  utilized in the lavatory trash can.

Depending on the manufacturer, the fire extinguishing bottles installed in engines, APUs, and cargo compartments must be removed at predetermined intervals for weight and hydrostatic testing. These scheduled maintenance intervals are controlled in calendar days or in flight hours depending on the extent to which an aircraft is used. For dual-turbine engines, there are typically two aircraft fire extinguisher bottles. The pilots can operate the fire extinguisher handle which shuts off all sources such as electrical power, pneumatic and fuel, and others. If an engine fire persists, the pilot can shoot the second bottle. This gives the co-pilot ample time to declare an emergency landing.

The APU is typically used on the ground, but can be used during flight as well. To extinguish a fire in the APU, you can follow a similar procedure as with turbine engines. Generally, there is a small fire extinguishing bottle exclusively for the APU. Avionics, on the other hand, lack a fire extinguishing bottle. As such, the pilot controls the air ventilation/cooling in the avionics bay in order to suppress oxygen levels.

Finally, the IFE compartments located in the passenger cabin use portable fire extinguishers which may be accessed by the flight attendants. Usually, the number of fire extinguisher bottles is proportional to the amount of passenger seats. Though aviation authorities forbid smoking in the lavatories, they are still equipped with an auto-discharge fire extinguisher system that consists of a fire extinguisher bottle in the waste disposal unit of each lavatory. When the temperature inside the waste compartment surpasses 77 degrees Celsius, the extinguishing agent is discharged to put out the fire.


If you find yourself in need of fire extinguishing agents, aircraft engine fire extinguishing system components, or aircraft engine fire detection system parts, rely on RFQ Experts. RFQ Experts is premier distributor of aircraft products and aerospace parts, all of which have been sourced from reputable manufacturers across the globe. Initiate the purchasing process with a competitive quote and see how RFQ Experts can serve as your strategic sourcing partner. For additional inquiries, call or email us directly; we are available 24/7x365! 


January 23, 2023

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