Source: Wall St. Journal
Authors: Jon Ostrower and Jack Nicas

United Airlines found improperly installed wiring on one of its Boeing Co. BA 787s, as operators of the new jet inspected their fleets after Monday's electrical fire on a Japan Airlines Co. Dreamliner in Boston, according to a person with knowledge of the U.S. carrier's actions.

United examined electrical components associated with the auxiliary power system, or APU, inside a small compartment underneath the cabin of the Dreamliner, an area known as the aft electrical-equipment bay, the person familiar with the inspections said.

The person said United found an improperly installed bundle of wires that connect to the APU battery, equipment that JAL and fire officials said ignited the blaze on the Dreamliner parked at Boston's Logan International Airport after passengers had deplaned.

The scrutiny of the Dreamliner after a succession of teething troubles intensified Tuesday when the 787 used for JAL's planned return flight from Boston to Tokyo was forced to return to the airport gate because of a fuel leak.

Boeing has said it is working with JAL after Monday's incident, but didn't respond to a request for comment about the issue discovered at United.

"We continue to work with Boeing on the reliability of our 787s." said Christen David, a spokesman for the unit of United Continental Holdings Inc..

A Boston airport official said the 787 used by JAL on Tuesday—a different jet from the one that caught fire—was taxiing toward the runway to take off for Tokyo when it started leaking fuel out of its left wing.

Matthew Brelis, a spokesman for the Massachusetts Airport Authority said the plane stopped and the fuel leak ceased at about 12:25 p.m. local time.

Airport crews were on the taxiway Tuesday afternoon cleaning up the spill, which Mr. Brelis estimated to be 40 gallons of jet fuel. The plane, which was still full of passengers, was to be towed back to the gate for evaluation, Mr. Brelis said.

The Federal Aviation Administration ordered mandatory inspections of 787s in early December, after concerns about leakage in fuel lines and engine attachments that were assembled improperly in the factory.