Japan's transport ministry said Monday safety inspectors had found no major problem on the production line making batteries for Boeing's Dreamliner, further muddying the waters in a worldwide probe.
“We have found no major quality or technical problem,” an official at the ministry said on condition of anonymity, as Japanese and American safety inspectors ended a week-long probe at battery maker GS Yuasa.
Shares in GS Yuasa, which has the contract for all Dreamliner batteries and is based in the western city of Kyoto, closed up 4.77 percent at 329 yen Monday after the ministry's comments.
Aviation regulators were focusing on the lithium-ion batteries as the cause of a problem that forced an All Nippon Airways (ANA) flight to make an emergency landing on January 16.
They have released a picture showing the blackened remains of the battery that inspectors removed from the plane.
But they said last week there were no signs of a battery fire, while information gleaned from the flight's digital data recorder showed the power pack did not suffer a rapid surge in voltage.
GS Yuasa is just one of many contractors in a complex global chain that led to three years of delays before Boeing delivered its first 787 to ANA in 2011.
The transport ministry official said Monday the authorities would now inspect suppliers of parts used in battery packs.
The Nikkei economic daily said they were looking into a company based in Fujisawa, southwest of Tokyo, which manufactures devices that monitor voltage and temperature in the batteries.
US regulators have said they will not allow the 787 to fly again until they are sure the problems around the battery system are fixed.
The worldwide grounding of the next-generation plane is having an increasing effect on airlines flying it.
ANA has reportedly cancelled 838 flights, affecting nearly 83,000 domestic and international passengers, over the period to the middle of next month. - AFP