In Washington, the National Transportation Safety Board said on Sunday that the battery on a Japanese plane that suffered a fire at a gate at Logan airport in Boston on Jan. 7 had not been charged beyond its maximum design voltage, 32 volts.

But on Tuesday, Kelly Nantel, a spokeswoman for the board, said that while the flight recorder had not indicated excessive voltage, that did not eliminate the possibility of charging problems. Experts in lithium-ion batteries said the batteries may have been charged too quickly, a possibility cited last week by Hideyo Kosugi, an investigator general for aircraft accidents in Japan.

In Japan, officials said on Wednesday that air safety investigators had asked the national space agency, JAXA, to examine the battery from the Air Nippon Airlines 787 that made the emergency landing last week. JAXA will conduct a scan of the battery. Experts from the company that built it, GS Yuasa, intend to take it apart afterward and examine each cell.

Ms. Nantel said her agency had given information to the Japanese on the progress in examining the Logan battery. It underwent CT scans and X-rays. “We’re sharing our experience,” she said. “They’re several days behind us.”

Senate aides in Washington are organizing a hearing to examine how the plane was certified by the Federal Aviation Administration. The administrator of the F.A.A. and the secretary of transportation, are expected to speak on Wednesday about progress of the inquiry.

The safety board is leading the American part of the investigation, but the F.A.A. will decide what fix is required and whether to let the plane return to service.

Article source: http://www.nytimes.com/2013/01/23/business/more-questions-are-raised-in-boeing-787-battery-fires.html?partner=rss&emc=rss