Battery maker GS Yuasa is being investigated by the Japanese transport ministry seeking to understand the two incidents involving Boeing 787 Dreamliner planes. This came following the grounding by the US Federal Aviation Authority of all Dreamliners.
GS Yuasa’s headquarters in Kyoto have been inspected by Japanese and American transport officials as part of the investigation after burn marks were found on the battery casing. The lithium-ion battery maker supplies batteries to Thales, the company that makes electrical systems for Boeing.
On 20th January the US National Transportation Safety Board said the first battery pack to catch fire "did not exceed its designed voltage." Yet the batteries remain the subject of inquiry.
On January 7th a minor fire in a Japan Airlines Dreamliner, whilst parked on a runway in Boston, has been linked to the plane’s battery pack. On 16th January smoke coming from the cockpit of an All Nippon Airways flight forced it to make an emergency landing at Takamatsu Airport.
The planes are fitted with lithium-ion batteries to power on-board electronics in the place of hydraulics used on older aircraft.
The inquiries must determine whether the batteries are defective or there is a design fault in the aircraft’s electrical systems.
A GS Yuasa official said: "Batteries are operated as a system in conjunction with peripheral parts. They don't catch fire or overheat on their own." The inspectors will return to the headquarters for further investigations.
Replacing batteries that have a manufacturing defect would be far easier and cheaper for Boeing than re-designing the electrical system, should that be shown to carry the problem.
The grounding of the planes has forced All Nippon Airways to cancel 335 flights this week.