What Are the Different Types of Fire Detectors Used on Aircraft?

While it is rare for an aircraft to catch fire, accidents and equipment malfunctions can happen, making it important to always have a fire detection system in place. As such, nearly all aircraft are fitted with automatic smoke, flame, heat, and gas detectors, all of which keep a plane and its occupants safe. While these sensors are most crucial to have in the engine compartment, it is common to find them placed throughout the vessel. With this, knowing the different types that may be present on an aircraft can be helpful for crew and passengers alike.

Types of Fire Detectors

Though any form of fire is significant on aircraft, it is important to make a distinction between those that can occur in-flight and post-crash. Of the two, in-flight fires are typically caused by equipment malfunctions or maintenance problems, while post-crash fires most often come as the result of the ignition of fuel released during a crash landing. Aircraft engineers and part manufacturers keep both types in mind when building and placing fire detection systems. Therefore, most airplanes feature a comprehensive collection of detector systems that safeguard the plane in the case of fuel leaks, engine fires, damaged equipment, and more. Specifically, you can find smoke, flame, heat, and gas detectors on aircraft, all of which are explained below.

Smoke Detectors

Smoke detectors are designed to provide early warning for a fire that is expected to progress through distinct smoldering stages. While smoke as a concept may seem simple, the type, volume, and density of smoke produced during an incident can give us great insight into the characteristics of the fire. For example, the greatest volume of visible smoke is usually produced during the ignition and smoldering stages. In addition to the different stages of a fire, there is also more than one type of smoke detector, with the two most popular being ionization and photoelectric types. Overall, knowing where a fire is in its ignition stages can help the crew decide on what actions to take, and smoke detectors are often one of the early indicators that something has gone wrong.

Flame Detectors

These kinds of detectors are primarily used to protect areas where anticipated fires will develop quickly with almost instantaneous ignition being typical. Rather than relying on unseen effects, these detectors are made to quickly respond to visual indication of flames via infrared light detection, ultraviolet light detection, or a combination of the two. Specifically, infrared (IR) flame detectors sense light at the high end of the light spectrum, whereas ultraviolet (UV) light detectors sense light on the other extreme end of the spectrum. Consequently, many aircraft employ combination UV/IR flame detectors which can capture a more complete spectrum of light, resulting in fewer false alarms.

Heat Detectors

Heat detectors are another common type used on aircraft, and they respond to the thermal energy of a fire. Generally located at or near the ceiling of a vehicle or building, these are best suited for fire detection in small, confined spaces where rapidly growing, high-heat output fires may be expected. They may respond to either a fixed temperature, a specified rate of temperature change, or both. Fixed temperature detectors can be either of the spot or continuous line variety and are designed to activate an alarm when the temperature of the operating element reaches a specific value. Conversely, rate-of-rise detectors are designed to activate when the rate of temperature change exceeds a predetermined value, typically around 15° per minute. Similar to flame detectors, heat detectors also come in a combination type that incorporates both rate-of-rise and fixed temperature detectors for greater accuracy.

Gas Detectors

Finally, there are gas detectors, which operate by sensing gasses produced by a fire. This device will only detect fires that burn with incomplete combustion and therefore produce significant quantities of gasses, as opposed to fires that burn with complete combustion and produce relatively little to no gasses.

Conclusion

There are many types of fire detection systems installed on aircraft to detect dangerous malfunctions. While some rely on visual indications, others can detect unseen effects like gas and heat to provide an early warning. For access to dependable aircraft devices such as fire detection systems, we at Single Source Spares invite you to browse our online catalog of items. Prioritizing quality and authenticity at every step of the way, we subject countless components to strict quality testing and high standards to ensure that they are always fit for use in aircraft. Explore our vast inventory and start the purchasing process today to experience a procurement process that is uniquely convenient and fit for your needs.