Malaysian crash investigators cast doubt that debris proves plane caught fire

Accident investigators on Thursday cast doubt on the possibility that blackened debris found on Madagascar is evidence of a catastrophic fire aboard the missing Malaysian airliner that went down more than two years ago.

Wreckage hunter Blaine Gibson hand-delivered five pieces of debris last week to officials at the Australian Transport Safety Bureau searching for Malaysia Airlines Flight 370.

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The bureau said in a statement Thursday that investigators had yet to determine whether the pieces were from the Boeing 777 that is thought to have plunged into the Indian Ocean with 239 people on board southwest of Australia on March 8, 2014.

A preliminary examination found that two fibreglass-honeycomb pieces were not burnt, but had been discoloured by a reaction in resin that had not been caused by exposure to fire or heat, the statement said.

There were three small areas of heat damage on one of the pieces thatcreated a burnt odour. However, that odour suggested the heat damage was recent, it said.

"It was considered that burning odours would generally dissipate after an extended period of environmental exposure, including salt water immersion, as expected for items originating from" the missing plane, the statement said.

Gibson has collected 14 pieces of debris potentially from the missing plane, including a triangular panel stenciled "no step" that he found in Mozambique in February. Officials say that panel was almost certainly a horizontal stabilizer from a Flight 370 wing.

Gibson had said the darkened surfaces of the latest debris could be evidence that a fire ended the flight far from its scheduled route from Kuala Lumpur, Malaysia, to Beijing. But he conceded he had no idea when the apparent heat damaged had occurred.

A sonar search of 120,000 square kilometres of seabed, which is calculated to be the most likely crash site in the southern Indian Ocean, is almost complete without any trace of the plane.