NTSB chief: Don't write off Boeing 787's battery just yet

The federal government's investigation into the battery problems that grounded the Boeing 787 Dreamliner is still "probably weeks away" from reaching a definite conclusion, Deborah Hersman, chairwoman of the National Transportation Safety Board (NTSB), said Wednesday.

The timetable Ms. Hersman offered at a Monitor-hosted breakfast for reporters is not good news for Boeing or for the airlines that own the 50 planes delivered so far. Without a precise diagnosis of the problem, regulators lack a blueprint to fix the battery issue.

Aviation regulators around the world told airlines to ground the new planes after a Jan. 7 battery fire on a Japan Airlines 787 parked at Boston's Logan Airport. Smoke from another 787’s batteries forced an All Nippon Airways plane to make an emergency landing in western Japan on Jan. 16.

The plane, which uses a variety of advanced technologies, is the first to use lithium-ion batteries – similar to those used in laptop computers. Two weeks ago, the NTSB released preliminary findings about the battery fire in Boston.

"There were short circuits in cells of the battery and there was a thermal runaway in the battery, multiple cells where we saw uncontrolled chemical chain reaction ... those features are not what we would have expected to see in a brand-new battery in a brand-new airplane," Hersman said at the breakfast.

She was careful not to say lithium-ion batteries are intrinsically dangerous for use in aviation.

"I would not want to categorically say that these batteries are not safe. Any new technology, any new design, there are going to be some inherent risks," she said. "The important thing is to mitigate them."

Hersman said she would announce on Thursday, at an NTSB press briefing, additional findings that could rule out some causes of the battery fire.

"We may not be able to say it was the battery in the billiard room with the wrench, but we might be able to say it wasn’t Colonel Mustard,” she said, referring to the board game Clue.

The NTSB is conducting what Hersman called a “very methodical” investigation and was “bringing in experts from all around government and around the world…. We are just really consulting with the best minds on batteries.” The result of this methodical approach, she said, was that "we are probably weeks away from being able to tell people, here is what exactly happened and what needs to change."