US and Japanese aviation safety officials finished an initial investigation of a badly damaged battery from a Boeing Co 787 Dreamliner jet on Friday as Boeing said it was halting deliveries until the battery concerns were resolved.
Boeing said it would continue building the carbon-composite 787, but deliveries were on hold until the US Federal Aviation Administration approved and implemented a plan to ensure the safety of potentially flammable lithium-ion batteries that prompted a widespread grounding of the new airplane this week.
In Washington, US Transportation Secretary Ray LaHood, said the 787 would not fly until regulators were “1,000 percent sure” it was safe.
A week earlier, LaHood said he would not hesitate to travel on a Dreamliner.
Officials from the US Federal Aviation Administration (FAA), US National Transportation Safety Board and Boeing joined Japanese authorities looking into what caused warning lights to go off this week on an All Nippon Airways Co domestic flight, prompting the aircraft to make an emergency landing at Takamatsu airport in western Japan.
The incident prompted regulators in the US and around the world to ground the 50 Dreamliners in service.
The jet has been flying safely for 15 months, carrying more than 1 million passengers, but it has run into problems in recent weeks, including problems with fuel leaks.
The biggest safety concerns centered on its lithium-ion batteries, which are lighter than conventional batteries, pack more energy and are faster to recharge, but are also potentially flammable.
When the FAA announced the grounding of all six US-operated 787s on Wednesday, the agency said airlines would have to show the batteries were safe and in compliance with its rules. It said both battery failures released flammable chemicals, heat damage and smoke — all of which could damage critical systems on the plane and spark a fire in the electrical compartment.
A Japanese safety official at Takamatsu airport told reporters that excessive electricity may have overheated the battery and caused liquid to spill out.
Pictures released by investigators of the battery showed a burnt-out blue metal box with clear signs of liquid seepage.
GS Yuasa Corp, the Japanese firm that makes batteries for the Dreamliner, said it sent three engineers to Takamatsu to help the investigation.
At a news conference, the Japan Transport Safety Board (JTSB) said the charred battery and the systems around it would be sent to Tokyo for more checks.
It said there were similarities with an earlier battery fire on a Japan Airlines Co 787 parked at Boston’s Logan International Airport.
“This information will go to Boeing and the FAA. They will assess it” before allowing the 787 to fly again in Japan, JTSB inspector Hideyo Kosugi said. He said the JTSB aimed to issue a report within a week but the US review might take longer.
LaHood said on Friday he could not predict when the 787 would resume flight.
The US investigation into that incident is focused on the Japanese-made batteries, with no indication the APU — built by United Technologies Corp’s Pratt & Whitney — was involved, said a person familiar with the government probe, who was not authorized to speak publicly.