Japan Airlines Co (JAL) said on Sunday that a Boeing Co 787 Dreamliner jet undergoing checks in Tokyo following a fuel leak at Boston airport last week had leaked fuel during tests earlier in the day.
An open valve on the aircraft caused fuel to leak from a nozzle on the left wing used to remove fuel, a company spokeswoman said. The jet is out of service after spilling about 40 gallons of fuel onto the airport taxiway in Boston due to a separate valve-related problem.
In Boston, a different valve on the plane opened, causing fuel to flow from the centre tank to the left main tank. When that tank filled up, it overflowed into a surge tank and out through a vent.
The causes of both the incidents are unknown, the JAL spokeswoman added.
There is no timetable for the plane to return to service.
On Friday, the U.S. government ordered a wide-ranging review of Boeing's 787 Dreamliner, citing concern over a fire and other problems, but insisted the passenger jet was still safe to fly.
JAL and local rival All Nippon Airways Co fly 24 of the 49 Dreamliners delivered to end-December.