Dreamliner fault tests focus on damaged battery

Engineers and aviation officials from the US and Japan are to subject a damaged lithium-ion battery from an All Nippon Airways (ANA) Boeing 787 jet to detailed tests.

They are expected to produce a report on the mishaps in Japan within a week, as the investigation continues into the new Dreamliner planes grounded by international regulators after a series of incidents.

The ANA jet was forced to land in western Japan on Wednesday after instruments on board indicated a battery error. Representatives from the US National Transportation Safety Board, the Federal Aviation Administration (FAA) and Boeing, along with local officials and engineers from GS Yuasa Corp, the Japanese company that makes the Dreamliner's lithium-ion batteries, have now completed initial checks on the jet at Takamatsu airport. The battery will be sent to Tokyo for more detailed analysis, a Japanese safety official said today.

Analysts have estimated that keeping the 787s on the ground could cost ANA alone more than $1.1m (£690,000) a day. Other carriers who have done the same include Japan Airlines, Air India and United Airlines.

"The impact of this incident on the aviation industry is great. That's why we feel the importance of swiftly producing a comprehensive report, free from bias," Hideyo Kosugi, an inspector from the Japan Transport Safety Board told a news conference. "We hope to produce a report as soon as possible … within a week."

The international investigation is understood to be focusing on the high-powered batteries used in the new plane. The new Airbus A380 also uses lithium batteries – but far less extensively than the 787, which draws on two units. Before the incident in Japan, another Dreamliner suffered a battery fire in Boston.

Attention in the US is also turning to the relationship between the FAA and the manufacturers whose products it certifies. In the 787 case, The Wall Street Journal reported that, as is routine, when it came to the new battery systems in the jet, the body relied extensively on data generated by Boeing itself.