NTSB updates: investigating cause of Boeing Dreamliner issues

by Stacy

WASHINGTON, D.C. (WCIV) -- The National Transportation Safety Board has not determined what caused issues on two Boeing 787 Dreamliners earlier this month, chairman Deborah Hersman said in a press conference Thursday.

"These things -- the short circuit, fire, the thermal runaway -- these are all symptoms something's wrong. Understanding why were seeing those symptoms, how they're related and what came first and what triggered the next thing, that's information we have yet to identify," Hersman said.

She said the NTSB could not say whether the battery caused the issues.

"We have not yet ruled anything out," she said.

One of the incidents happened in Boston, while the other occurred in Japan, she said. NTSB investigators are working with Japanese investigators, Hersman added. She said the government hasn't grounded a plane in decades.

"This is an unprecedented event. We are very concerned. As I mentioned in the beginning, we do not expect to see fire events on board aircrafts. This is a very serious air safety concern."

Investigators have examined the new batteries used in the 787s. Hersman said they have performed CT scans and used an internal microscope on the batteries. She also said there is no evidence an involved{}battery was overcharged.

"This is a very interesting technology. It's novel," she said.

Hersman did not give a time frame for the investigation length. She also said the NTSB is working with Boeing and the Federal Aviation Authority to evaluate the process before Dreamliners took flight.

"Were certification standards adhered to and were they appropriate?" she said.

None of the grounded planes was produced at Boeing's plant in North Charleston.