An explosion inside an engine of a Japan Airlines passenger jet in August over Fukuoka Prefecture is believed to have been caused by deterioration of the engine's turbine blades, according to an interim report released Wednesday by the engine's manufacturer.

Pratt & Whitney of the U.S. stated in its report that the deterioration prevented the engine of the JALways DC-10 from cooling properly.

The company carried out an inspection of the engine following the accident.

Officials of the Land, Infrastructure and Transport Ministry and JAL said it was likely the blast occurred after the turbine blades overheated and they are asking Pratt & Whitney to compile a full report on the incident.

According to the airline, of the six turbine tiers, which are located near the back of the engine, the damage was most visible from the second turbine and rearward. Officials said they suspect the accident was caused by the breaking of the roughly 100 blades in the second turbine.

After examining the engine, Pratt & Whitney found that the wings that adjust the flow of combustible gas that are located near the second turbine were worn down. This indicates the blades themselves were probably worn, thus preventing the proper flow of cooling air.

Turbine blades are designed to withstand a temperature of up to about 1,100 degrees. Deterioration of the blades is thought likely to occur after tiny objects are caught in the engine.

Following a similar incident involving a DC-10 in June 2001 at Nagoya airport, Pratt & Whitney instructed airlines to inspect the turbine blades for wear every 2,000 hours to 3,000 hours of operation.

JAL has said it followed the instructions.