I am certain that you’ve come across news reports featuring deflated airplane tires following a rejected take-off or an emergency landing soon after take-off. Some might speculate that the tires blew up, but if that were the case, the tires would appear ripped apart. Instead, the images we see often show aircraft tires that are deflated, resembling flat automobile tires. The reason why they deflate is due to a safety feature designed to prevent the aircraft tires from exploding. The presence of what is known as a “fuse plug” in the tires.
Airplanes are equipped with various safety features, one of which is the wheel fusible plug, commonly known as the “fuse plug.” These components play a critical role in ensuring the safety of the aircraft, particularly during high-energy events like a rejected takeoff (RTO).
How Fuse Plugs Work
Fuse plugs are installed in the wheels of all airplanes. They are made of a metal alloy with a low melting point and are fitted into holes drilled in the landing gear wheels. The primary function of these plugs is to prevent tire explosions that might occur due to excessive heat and pressure build-up within the tires. During events like a high-energy RTO, where the wheels become excessively hot, the fuse plugs melt, allowing the tire pressure to be safely released.
In the aftermath of a high-energy RTO, it’s common to see deflated tires. This deflation is a direct result of the action of the wheel fuse plugs, which have melted due to the excessive heat generated by the brakes. This mechanism is a testament to the intricate safety systems designed to protect the aircraft and its occupants.
Considerations for Short-Haul Operations
Operators engaged in short-haul operations, characterized by short flight and ground times, should be particularly mindful of the cumulative nature of brake energy. It’s relatively easy to heat up the brakes, but cooling them down is a more challenging task.
In a typical short-haul operation, the first landing might not cause the fuse plugs to melt, but it does introduce kinetic energy into the brakes. Given the limited ground time, there’s minimal opportunity for the brakes to cool down. Similarly, short flight times offer limited cooling as well. With each subsequent landing, more kinetic energy is pumped into the brakes, gradually increasing their temperature.
If this cycle of heating without adequate cooling continues, the fuse plugs are likely to reach their melting point eventually. To prevent this, operators must take proactive measures to ensure sufficient cooling of the brakes, especially in high-frequency, short-haul flight operations.
This explains why aircraft tires automatically deflate during a high-energy RTO. The tires don’t explode; rather, they deflate as a safety precaution. This is because the energy from an exploding tire could puncture the fuel tanks and potentially cause further damage to the aircraft.
First love never dies. I fell in love with airplanes and aviation when I was a kid. My dream was to become a pilot, but destiny led me to another path: to be an aviation digital media content creator and a small business owner. My passion for aviation inspires me to bring you quality content through my website and social accounts. Aviation is indeed in my blood and blog!
