An incident Monday “appears to have involved the venting of a single battery cell” on a 787 operated by Japan Airlines while it was undergoing routine maintenance in Narita, Japan, according to news release from Boeing.
The planemaker and airline are investigating the incident. No cause was immediately apparent.
Nearly a year ago, the 787 was grounded worldwide after experiencing smoke and overheating produced by lithium-ion batteries, including a Japan Airlines plane on the ground in Boston.
No one was aboard the jet Monday at Tokyo’s Narita airport as it was prepared for a flight to Bangkok, and JAL put another 787 on that trip, said Seiji Takaramoto, a spokesman for the carrier.
A JAL mechanic discovered smoke from under the fuselage, and an inspection found a safety valve on one of eight battery cells had opened and vented liquid, Takaramoto said. The other seven cells were intact, Takaramoto said. Cockpit instruments showed a possible fault in a main battery and a main battery charger, he said.
Lithium-ion batteries on Dreamliners melted down twice in January 2013, spurring regulators to order the planes parked worldwide while Chicago-based Boeing crafted a fix. The Federal Aviation Administration cleared the way for Dreamliner flights to resume three months later.
The redesign included new components to minimize potential of a short-circuit, battery insulation between cells to halt the spread of fire and a new heat-resistant case and venting system. The battery enclosure was intended to ensure that fire can’t develop inside, while the voltage range of the batteries, made by Kyoto, Japan-based GS Yuasa Corp., was also limited.
“The improvements made to the 787 battery system last year appear to have worked as designed,” according to Boeing’s statement Tuesday. “Since certification of the enhanced 787 battery system in 2013, and the return to service of the 787 fleet, this is the first indication of a battery cell failure.”
No cause for the 2013 failures was ever found. The fixes were designed to head off every possible way the batteries can fail, FAA Administrator Michael Huerta told Congress in February.