Investigators ponder Boeing 787 battery problems

U.S. safety regulators are nowhere near finishing an investigation into a battery fire on the Boeing 787 Dreamliner.

Deborah Hersman, who chairs the National Transportation Safety Board says regulators were taken by surprise.

(SOUNDBITE) (English) DEBORAH HERSMAN, CHAIR OF THE NATIONAL TRANSPORTATION SAFETY BOARD (NTSB) SAYING:

"What I will tell you, we do not expect to see, events like what we saw on the 787 with the battery system. This aircraft has been in the air for less than 100 hours., and to see two battery events within two weeks in the early flights of this aircraft, is not what we would expect."

She says they are still trying to figure out what caused the problems.

(SOUNDBITE) (English) DEBORAH HERSMAN, CHAIR OF THE NATIONAL TRANSPORTATION SAFETY BOARD (NTSB) SAYING:

"What we have shared with you today is characteristics that we have identified. What we have not told you , is what caused this. We are looking at this evidence and we have to determine whether it is cause of effect. We are seeing symptoms."

Boeing and its regulators say they do not know when the 787 will fly again.