TOKYO, Jan. 14 (UPI) -- Japan Airlines said smoke was seen in one of its Boeing 787 Dreamliner jets during a preflight check at Tokyo airport, causing the plane to be grounded.
The incident Tuesday at Tokyo's Narita International Airport comes about a year after the Dreamliner jets were grounded around the world due to battery problems, which subsequently led to Boeing to make modifications in the planes' battery system.
Kyodo News quoted JAL that the maintenance crew at the Tokyo airport found white smoke coming out of the lower part of the fuselage Tuesday afternoon before the plane was due to depart for Bangkok.
The airline later said a venting valve for one of the eight lithium-ion battery cells, which was one of the modifications made by the aircraft maker last year, had been activated. The valve is designed to release pressure in the battery cells when they overheat, the report said.
It was not immediately known what caused the incident, but Kyodo quoted Boeing as saying: "Improvements to 787 battery system appear to have worked as designed." The message said the company is working with JAL to return the plane to service. JAL has 12 other Dreamliners.
The Wall Street Journal quoted Boeing as saying it had informed other airlines with 787 planes but had not asked them to take any action. The report said United Continental Holdings, the only U.S. airline operating the aircraft, was flying their Dreamliners normally Tuesday.
The report quoted a spokeswoman for the U.S. Federal Aviation Administration that the agency was working with Boeing and the Japan Civil Aviation Bureau in looking into the incident. Separately, the U.S. National Transportation Safety Board expressed readiness to assist Japanese officials.
Hans Weber, president of consulting firm Tecop International Inc., told the Journal the latest incident was unlikely to result in any new major regulatory step as the earlier modifications by Boeing seem to have taken care of the battery problem.
The Journal quoted a JAL spokesman that the airline Wednesday was working to replace the battery and that the plane may be allowed to resume service if no problems are found.
Separately, All Nippon Airways, the other Japanese carrier with 23 Dreamliners, was operating the planes normally.
CNN said Boeing has spent hundreds of millions dollars in designing the 787 Dreamliner, which is lighter and more efficient.