NTSB, Boeing address 787 fire; United finds wiring error

Here are new developments regarding Boeing 787 problems since this morning's blog post:

• Boeing Co. and the National Transportation Safety Board confirm that the fire that broke out yesterday on a Japan Airlines 787 has been traced to the battery used to start the aircraft's auxiliary power unit.

In its initial report released Tuesday, the NTSB said the battery sustained "severe fire damage."

"Thermal damage to the surrounding structure and components is confined to the area immediately near the APU battery rack (within about 20 inches) in the aft electronics bay," NTSB writes.

The NTSB has three investigators looking into the incident. The Federal Aviation Administration, Boeing, Japan Airlines and a representative of the Japan Transport Safety Board also are investigating.

In a statement released Tuesday, Boeing says it would be premature to discuss details. However, the company said it does not think previous incidents involving 787 electrical components are related to this latest one.

"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 in an emailed statement.

• The Wall Street Journal reports that United Airlines has found wiring problems on one of its 787s.

The airline found an improperly installed bundle of wires that connect to the APU battery, an unnamed source told the Journal.

• Also this morning, another Japan Airlines 787 had trouble in Boston. About 40 gallons of fuel leaked from the plane prior to takeoff, after it left the gate. The jet was towed back to the gate for evaluation.

The FAA previously instructed airlines to inspect 787s for fuel leaks.

• The price of a share of Boeing stock fell again Tuesday, by $2 to $74.13. That's 2.6 percent. Yesterday after the fire was first reported, the stock fell 2 percent.