Battery problems resurfaced on Boeing's 787 on Tuesday, after gas was discovered coming out of a battery on a plane parked at Tokyo's main international airport.
Boeing said the problem on a Japan Airlines 787 was discovered during scheduled maintenance. No passengers were on board on the flight. The company said it appears that a single battery cell "vented," or released gas.
Japan Airlines said a mechanic briefly saw white smoke rise from the area below the cockpit but there was no sign it burned.
The battery has been removed from the aircraft for further investigation at its maker, GS Yuasa. JAL spokesman Kentaro Nakamura said the cause was under investigation and may take some time. He said Boeing officials were expected to join the probe in Japan.
He said the latest incident was unfortunate but "it demonstrated that the safety measures taken last year have actually functioned."
Nakamura said JAL has no immediate plans to ground other 787s it operates.
The incident comes a year after a fire in a lithium ion battery aboard a Japan Airlines 787 parked at Boston's Logan International Airport. That was followed nine days later by another battery incident that forced an emergency landing in Japan by an All Nippon Airways 787.
Those problems prompted the FAA and other authorities to ground all 787s for more than three months. The planes began flying again after Boeing changed the battery system, adding a tougher box to hold the battery and measures to contain any short-circuit or fire.
Boeing said those changes appear to have worked as designed in the battery incident on Tuesday. It said it's working with Japan Airlines to get the plane flying again.
JAL said a mechanic saw from a cockpit window white smoke that lasted briefly and there was no sign that the battery caught fire.
Because the incident happened in Japan and involved a Japanese airline, Japanese authorities would take the lead in any investigation. If the Japan Transport Safety Board opens an investigation, the U.S. National Transportation Safety Board "would certainly participate," NTSB spokesman Peter Knudson said. The NTSB said the incident was reported to it as a "smoke event."
The NTSB expects to finish its investigation of the 787 fire in Boston by the end of March, and present findings at a public meeting this fall.
"Anything we can learn about the (latest) battery failure would be helpful" to the ongoing investigation, Knudson said.
The Federal Aviation Administration said it is working with Boeing and with the Civil Aviation Bureau of Japan to investigate the latest malfunction.
United Airlines is the only U.S. 787 operator. "Our 787s are operating normally, and we haven't experienced any issues with the batteries," spokeswoman Christen David said.
She declined to say whether United 787s were getting extra inspections, beyond the routine maintenance checks the airline gives all of its planes.
Boeing shares fell 69 cents, or a half-percent, to close at $140.01 on Tuesday.
AP transportation reporter Joan Lowy in Washington and AP writer Mari Yamaguchi in Tokyo contributed to this report.