One Japanese inspector described the battery as like ‘burned stew’ US and Japanese experts on Friday probed the emergency landing that sparked the worldwide grounding of Boeing's Dreamliner, releasing a picture showing the blackened remains of the plane's battery. The risk of fire from overheating powerpacks has emerged as a major concern for Boeing's cutting-edge new planes since the incident on the domestic flight in Japan, prompting airlines to ground all 50 of the world's operational 787s.
The All Nippon Airways Dreamliner has remained on the tarmac at Takamatsu in southwest Japan since its pilots were forced to abort the flight on Wednesday because of a smoke alert apparently linked to the lithium-ion battery.
A team from the US National Transportation Safety Board, which includes members from the FAA and Boeing, has arrived in Takamatsu to take part in the Japanese investigation, a spokesman for the Japan Transport Safety Board said.
"We removed the battery yesterday and are today inspecting the plane and its components, alongside the US officials," said the spokesman, Mamoru Takahashi.
A picture released by the JTSB showed scorch marks on the blue casing of the battery, which also showed evidence of some kind of dark liquid that appeared to have leaked down the side.
The lid of the battery casing had bulged out of shape and become badly discoloured. Much of what looked like wiring around the eight cells of the battery -- the plane's main electrical power unit -- was disfigured.
A Japanese investigator who had seen the battery was reported as saying the overspill looked like burned stew.
"You know how stew in a pot would boil, spill over and harden, it was like that," he said, according to TV Asahi.
The batteries used for the Dreamliner's advancedelectronics are made by Japan's GS Yuasa, 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.
JTSB investigator Hideyo Kosugi said one theory being considered was that there may have been insufficient protection offered by the batteries' surrounding electrical system, which would also come under scrutiny.
"I'm sure that too much current or too-high voltage has gone to the battery," Kosugi told reporters.
A prolonged grounding could seriously compound problems for Boeing, which suffered a series of glitches over 10 days leading up to the ANA incident including another smoke alert on a Japan Airlines Dreamliner at Boston airport.
Hans Weber, an independent security and defence expert, said Boeing had been too optimistic about the benefits of its worldwide outsourcing strategy to build the 787.
"Boeing has admitted that it underestimated the level of management oversight and engineering support it needed to provide to its suppliers to make the highly distributed supply chain work," he told media in the United States.
"If Boeing had done a better job at that, it would not have experienced the technical problems it has, in my opinion."
The US firm is banking on strong global demand for an all-new design based on lightweight composite materials that is much more fuel-efficient than older aircraft. It has won orders for nearly 850 more 787s.
All of the 50 Dreamliners already flying -- in Chile, Ethiopia, India, Japan, Poland, Qatar and the United States -- have now been taken out of service after a global alert issued this week by the US Federal Aviation Administration.
Polish flag carrier LOT -- the only European operator of the 787 so far -- said it still expected to take delivery of three more planes before the end of March, provided any defects on the plane are eliminated.
But Australia's Qantas said it was cutting its request for Dreamliner planes by one, while noting it had planned to do so before the jets were grounded and that it still had 14 on order.
Source: AFP