Boeing 787 aircraft grounded after battery problem in Japan
Japan Airlines has grounded a Boeing 787 Dreamliner aircraft after detecting smoke or gases that may have come from faults with the main battery.
The problem was discovered during routine maintenance, and is a reminder of the battery faults that grounded all 787s for three months last year.
The airline said engineers noticed smoke, and then warning lights flashed signalling a battery fault.
Boeing said it was aware of the issue and is working with Japan Airlines.
The aircraft maker said that early indications suggested that a single battery cell had released gases, and that the warning system had operated as planned.
No passengers were on board.
The company's shares price initially fell 1.5%, but eased backed later.
Any 787 battery problem is a sensitive issue. The worldwide fleet of Dreamliners was grounded last year while investigators looked into why two batteries on separate aircraft overheated in less than two weeks.
Boeing redesigned the battery system, although the precise cause of the problem was never conclusively proved.
Richard Westcott, the BBC's transport correspondent, said: "Boeing says it appears that one cell within the lithium ion battery had gone wrong. The number of cells is highly significant.
"There are eight in total for each battery, and if the chemicals spread from one to the next it can potentially start a fire.
"Boeing never did solve the battery problem that grounded the entire Dreamliner fleet last year. Instead, Boeing put in a raft of safety measures to contain any future issues."
There are 115 Dreamliners currently in service with 16 airlines.