US investigators ask Boeing for battery history

National Transportation Safety Board spokesman Peter Knudson said the agency made the request after becoming aware of battery problems at ANA that occurred before two recent incidents involving the planes batteries. Boeing has already collected some of the information, he said.

All 50 of the Boeing 787s in use around the world remain grounded after an ANA flight on Jan. 16 made an emergency landing in Japan when its main battery overheated. About a week before that, a battery caught fire in a 787 parked at Boston's Logan International Airport.

ANA said it had replaced batteries on its 787 aircraft some 10 times because they didn't charge properly or connections with electrical systems failed, and informed Boeing about the swaps. Japan Airlines also said it had replaced 787 batteries. It described the number involved as a few but couldn't immediately give further details.

The 787 is the first airliner to make wide use of lithium-ion batteries. They are prone to overheating and require additional safeguards to prevent fires. However, ANA spokeswoman Megumi Tezuka said the airline was not required to report the battery replacements to Japan's Transport Ministry because they did not interfere with flights and did not raise safety concerns.

Boeing said Wednesday that replacing the batteries on a plane is not uncommon. The company said that it has not "seen 787 battery replacements occurring as a result of safety concerns."

The ANA spokesman also said that replacing batteries on aircraft was not considered out of the ordinary.

Laura Brown, a spokeswoman for the U.S. Federal Aviation Administration, said in Washington that the agency was checking whether the previous battery incidents had been reported by Boeing.