A Japan Airlines Boeing 787-8 experienced a fuel leak while preparing for take-off at Boston Logan International Airport, a day after another of its 787s had a fire on board while parked at the same airport.
The aircraft, with registration JA824J, was taxiing before take-off on 8 January when it was instructed to make a ground turn back at 13:31 local time.
A fuel valve was found to be open and this led to fuel flowing into the aircraft's left wing surge tank, thus causing a fuel leak, says a JAL spokeswoman.
"The valve was eventually deactivated and the aircraft was able to depart again," she adds.
The aircraft took off at 16:03 local time, after a four-hour delay, to Tokyo Narita airport.
The exact cause of the incident is still being investigated, and it has not yet been determined whether further checks need to be done on the airline's fleet of seven 787s, says the spokeswoman.
JAL had already conducted additional inspections on its 787s after one of its aircraft's lithium ion batteries located in the aft electrical bay exploded while it was parked on 7 January. The explosion caused a secondary fire that had to be extinguished by firefighters at the airport. The US National Transportation Safety Board is still investigating the incident.