A Japan Airlines Boeing 787 that was to fly to Tokyo was grounded in Boston on Tuesday following a fuel spill, one day after another plane of the same type suffered a fire, government officials said.
"Japan Airlines flight 7 was leaking fuel" as it was taxiing before taking off, said Matthew Brelis, a spokesman for Massport, the local airport authority. Around 40 gallons of fuel spilled, according to Brelis.
Since the incident around midday, the spill has been stopped and the tarmac cleaned up, Brelis added.
The plane is currently being analyzed and the reasons for the problem are not yet known, said a spokesperson for JAL.
After the aircraft returned to the gate, passengers disembarked the aircraft, said the JAL spokeswoman.
It was the second incident involving a Boeing 787 in two days.
On Monday, a smoky fire broke out on another JAL aircraft of the same model after it landed in Boston from Japan.
A Boeing statement said it would be "premature" to discuss Monday's incident prior to a complete investigation.
The National Transportation Safety Board, which rushed three inspectors and a technical team to the sight, opened an official investigation into the Monday incident. The NTSB said the fire was the result of an electrical problem.
The two incidents come as Boeing accelerates production of its mid-sized, long-range Boeing 787 Dreamliner despite other recent incidents involving the plane.
The Boeing statement said Monday's incident was not analogous to the earlier cases.
"Nothing that we've seen in this case indicates a relationship to any previous 787 power system events, which involved power panel faults elsewhere in the aft electrical equipment bay," Boeing said.
JAL, along with fellow Japanese firm All Nippon Airways, is one of Boeing's most important clients, with 45 orders for the 787.