Investigators still unable to find cause of 787 Dreamliner fire

WASHINGTON (REUTERS) - Further testing still has not found the cause of a battery fire aboard a Boeing Co 787 Dreamliner in Boston earlier this month, the National Transportation Safety Board said on Sunday.

In a statement released on Sunday, the safety regulator said"no obvious anomalies were found" in its initial investigation of an undamaged battery aboard the plane and that a more detailed examination would follow.

The NTSB's preliminary finding, along with the absence of any reported progress in determining a root cause of the auxiliary power unit's battery fire, underscores that the safety investigation and the grounding of 787s may drag on longer than Boeing had hoped.

Oliver McGee, an aerospace and mechanical engineer who was a deputy assistant secretary of transportation for technology policy under President Bill Clinton and a former consultant to Boeing, described the challenge facing the investigators as a"megascale engineering puzzle."