What does a deflated main gear tire due to a thermal fuse melt indicate?

A deflated main gear tire due to a thermal fuse melt indicates that high tire temperatures have melted a fusible metal plug installed in the aircraft wheel. This fusible plug is designed to act as a safety feature. It is a metal that melts at a specific temperature to relieve pressure and prevent more severe damage or failure of the wheel assembly under extreme conditions, such as overheating.

When the temperature within the tire exceeds the safety threshold due to prolonged wear, a heavy landing, or insufficient cooling during taxiing, the melted plug allows the air to escape. This prevents the tire from bursting or causing further damage to the aircraft system. Thus, the deflation due to the thermal fuse melt is a clear indication of excessive heat exposure rather than mechanical failure or external damage to the tire itself.