From the report above:
The characteristics of the sidewall damage observed on all four of the accident airplane’s tires were consistent with a photograph in a Goodyear publication showing typical heat damage sustained from sidewall overdeflection and flexing fatigue. Goodyear engineers and the Goodyear publication noted that previous tire testing found that aircraft tire sidewall damage from flexing fatigue is predominantly consistent with taxi-cycle operations while the tire isunderinflated; Goodyear testing showed that as little as 5-percent underinflation greatly reduces the fatigue life of transport-category aircraft tires.
...
Other damage observed on fragments from each of the accident airplane’s tires included blue to purple heat discoloration indicative of moderate to severe heat damage. According to the Goodyear publication, blue tinting appears at temperatures from 210° to 230° F. Microscopic examination of fragments from all four tires revealed that the tires’ nylon fibers (which are generally soft and fabric-like when undamaged) had melted and resolidified into single strands that had a stiffness resembling that of broom bristles. The Goodyear publication noted that the melting point of nylon is greater than 400° F. Rubber reverts to an uncured state and loses strength and adhesion at temperatures from 280° to 320° F, then becomes hard and dry at temperatures from 355° to 390° F.
given that all four of the main tyres in the Dili aircraft failed, and they look like sidewall failures, it does point to overheating from under inflated tyres.
The report also says:
The contents of chapter 12 of the AMM related to technical specifications and descriptions of how to perform various maintenance tasks. Chapter 12-10-05, pages 301 and 302, contained the following guidance:
Important inflation practices and tips are as follows:
... Measure the cold tire pressure before the first flight of every day or every 10 day[s] on in-service tires [that] are not in use....
Do not underinflate the tire. An underinflated tire generally cannot be detected visually.
The AMM indicated that a tire should be replaced if found to have operated at an inflation pressure loss of 15 percent.