A patch of tread rubber is melted or scorched.
An oval shaped burn on the tread most often is caused by hydroplaning on wet or frozen runways during landing.
If the tread rubber reversion reaches the reinforcing fabric (bias) or aramid cord protector (radial), remove the tire from the aircraft.
If the tread rubber reversion does not reach the reinforcing fabric (bias) or aramid cord protector (radial), if there is sufficient groove depth in the whole tread rubber reversion area, if there is hot incipient separation and if vibration is not detected while rolling, leave the tire on the aircraft.