LONDON Aviation officials have widened their investigation into the cause of a battery fire on a Boeing Co. 787 Dreamliner after confirming that the battery did not overcharge.
Two separate incidents involving Dreamliner aircraft have led to the launch of several investigations and the grounding of planes in recent weeks.
The National Transportation Safety Board (NTSB) released a third update of its investigation into the first incident, a fire aboard a Japan Airlines Co. Ltd. Boeing 787 at Bostons Logan International Airport.
An examination of the flight recorder data from the aircraft indicate that the battery "did not exceed its designed voltage," the board noted.
The investigation is ongoing, and NTSB investigators continue to look at the wider battery system.
Chicago-based Boeing halted Dreamliner deliveries after a problem with a lithium-ion battery on a second 787 plane, flown by All Nippon Airways Co. Ltd., forced the plane to make an emergency landing Jan. 16 in western Japan.
Tokyo-based All Nippon Airways apologized after the incident, adding that it was registered as a serious incident by Ministry of Land, Infrastructure, Transport and Tourism.
"We sincerely apologize to everyone affected by the inconvenience and concern caused by this incident," All Nippon Airways said on its website. The airline has suspended all operations of its Boeing 787 aircraft.
Meanwhile, governments around the world also have grounded the Dreamliner as investigations continue.
"The Federal Aviation Administration (FAA) will issue an emergency airworthiness directive (AD) to address a potential battery-fire risk in the 787, and require operators to temporarily cease operations. Before further flight, operators of U.S.-registered Boeing 787 aircraft must demonstrate to the FAA that the batteries are safe," the agency said.
"The battery failures resulted in release of flammable electrolytes, heat damage and smoke on two model 787 airplanes," the FAA added.
Boeing is "confident the 787 is safe," the company said.
"There is no higher priority than the safety of passengers and crew members flying onboard our airplanes," the company said. "Boeing is committed to supporting the FAA and finding answers as quickly as possible. The company is working around the clock with its customers and the various regulatory and investigative authorities."
Meanwhile, the NTSB has assigned an accredited representative to assist with the investigation of the second battery incident involving the All Nippon Airways 787.
A probe of Kyoto, Japan-based GS Yuasa Corp., the maker of the lithium-ion batteries used in Boeings grounded 787 jets, has reportedly begun in Japan.
A version of this article was first published by AMM sister publication Metal Bulletin.