TOKYO (AP) — Japanese and U.S. investigators began a probe into the maker of the lithium ion batteries used in Boeing's grounded 787 jets.
Tsutomu Nishijima, a spokesman for GS Yuasa, the battery manufacturer, said investigators visited the company's headquarters in Kyoto, Japan, on Monday and that Yuasa was cooperating with the probe.
Investigators with the National Transportation Safety Board were slated to be in Phoenix Tuesday to talk to officials at UTC Aerospace Systems, the company that built the plane's auxiliary power controller.
Investigators also planned to meet Tuesday with officials from
, manufacturer of the charger for the 787s lithium ion batteries, at the company's headquarters in Tucson, Ariz., board spokeswoman Kelly Nantel said.
All 50 of the 787 Dreamliners that Boeing has delivered to airlines were grounded after an overheated battery forced the emergency landing of an All Nippon Airways 787 flight last week in western Japan. Boeing has halted deliveries of new planes until it can address the electrical problems.
Monday's investigation involved an introductory meeting and factory tour, with deeper studies into product quality and other issues to follow as the probe continues, said Tatsuyuki Shimazu, the chief air worthiness engineer at the Civil Aviation Bureau's Aviation Safety Department.
Two investigators from the U.S. Federal Aviation Administration and an investigator from Japan's government were conducting the probe into how the batteries are made and assembled and into any quality issues, he said.
"We are in the midst of collecting information, so as to whether there is a problem or not has not yet been determined," Shimazu said.
Nishijima of GS Yuasa said he could not comment on details of the investigation.
The burned insides of the ANA battery showed it received voltage in excess of its design limits. However, a battery that caught fire in a Japan Airlines Boeing 787 in Boston earlier this month was found not to have been overcharged.
U.S. government investigators said there could still be problems with wiring or other charging components.
Boeing posted a statement about the battery incident and subsequent federal investigation on its website last week.
"The safety of passengers and crew members who fly aboard Boeing airplanes is our highest priority.
"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. We will make available the entire resources of The Boeing Company to assist.
"We are confident the 787 is safe and we stand behind its overall integrity. We will be taking every necessary step in the coming days to assure our customers and the traveling public of the 787's safety and to return the airplanes to service.