Massachusetts Port Authority spokesman Richard Walsh said the Boeing 787 was towed back to the gate for evaluation early Tuesday afternoon after about 40 gallons of fuel spilled. He said the plane had 178 passengers and 11 crew members on board.
A JAL spokeswoman said the crew reported a "mechanical issue" before returning to the gate.
On Monday, a fire broke out in a battery pack in the belly of a different Japan Airlines plane, filling the cabin with smoke minutes after passengers disembarked.
The Federal Aviation Administration and National Transportation Safety Board are investigating the fire.
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