January 20, 2013 6:59 pm

Battery finding may delay Dreamliner

An ANA Dreamliner is examined at Tokyo's Haneda airport on January 16 following safety concerns©Reuters

The resumption of Boeing 787 Dreamliner flights could be further delayed after a top US investigator ruled out excessive voltage as the cause of a battery fire that led to the grounding of the aircraft around the world.

The National Transportation Safety Board said in a statement on Sunday that flight recorder data from the Japan Airlines Dreamliner which suffered a battery fire on January 7 indicated that the lithium ion battery “did not exceed its designed voltage”.

That contradicts preliminary findings from Japanese authorities on Friday, which suggested that excessive electricity in the battery of an All Nippon Airways 787 had been the cause of its emergency landing there last week.

A faulty batch of batteries might have meant a quick fix and a swift return to the skies. But if regulators discover more fundamental problems with the Dreamliner’s electrical power system, requiring an extensive redesign, the grounding could last several months.

That could force Boeing to curb its ambitious plans to double 787 production to 10 per month by the end of the year. In light of the incidents, the company has already halted deliveries of the aircraft, which arrived three years behind schedule in 2011.

The lithium-ion batteries are part of the aircraft’s innovative electrical power system, which has helped make it the world’s most technologically advanced jet. The Federal Aviation Administration, the top US regulator, said the grounding could only be lifted once Boeing “demonstrate[s] to the FAA that the batteries are safe”.

Because of similar burn marks inside the batteries found in both incidents, investigators and commentary have focused on the lithium-ion technology, supplied by Japan’s GS Yuasa Corporation.

Boeing has released multiple statements since the first incident reaffirming its confidence in the 787’s safety and its continued co-operation with investigators.

The NTSB said the lithium-ion battery had been X-rayed and put through a CT-scan before being disassembled into its eight individual cells for more detailed evaluation. Investigators also examined wire bundles and battery management circuit boards as well as other components.

Investigators will conduct further tests on Tuesday and at a later date, officials will also head to a facility run by Pratt & Whitney in Phoenix, Arizona, for more evaluations, according to a Reuters report. Several components have also been sent for tests to Boeing and to manufacturers in Japan.

Hideyo Kosugi, a Japan Transport Safety Board investigator, told Reuters on Sunday that his agency would take the US statement into account as it began its probe.

“The NTSB’s investigation started earlier. We still haven’t taken X-rays or CT-scans of the battery . . . as the third party organisation where the Japanese investigation would take place still has not been chosen,” he said.

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