Why are fusible plugs installed on some aircraft wheels?

Fusible plugs are specifically designed to enhance safety in aircraft wheels by responding to excessive heat generated during operations. When the temperature rises due to rapid wheel rotation or brake application, the fusible plug melts at a predetermined temperature. This melting creates an opening that allows compressed air or tire pressure to escape, thus preventing the tire from blowing due to overpressure caused by heat build-up. This mechanism is crucial because it mitigates the risk of catastrophic failure that can occur if a tire bursts while on the ground or during takeoff, which could lead to loss of control.

The role of fusible plugs is focused on pressure relief in the event of overheating, rather than on tire wear, pressure balance, or shock absorption, which are not their intended functions.