In the first battery incident on Jan. 7, it took firefighters 40 minutes to put out a blaze centered in an auxiliary power unit of a Japan Airlines 787. The plane was empty of passengers shortly after landing at Boston's Logan International Airport.
The two incidents resulted in the release of flammable electrolytes, heat damage and smoke, the FAA confirmed. The release of battery fluid is especially concerning, safety experts said. The fluid is extremely corrosive, which means it can quickly damage electrical wiring and components. The 787 relies far more than any other airliner in operation on electronics to function rather than hydraulic or mechanical systems.
The electrolyte fluid also conducts electricity, so as it spreads it can short circuits, interfere with electrical signals and make control of the plane impossible for pilots and ignite fires. And its corrosiveness raises concern about whether a leak might weaken a key support structure of the plane, even though the 787 is the first airliner to be made primarily from lightweight composite materials that are less susceptible to corrosion than aluminum, safety experts said.
"Anytime you have leakage of battery fluid it's a very serious situation," said Kevin Hiatt, president and CEO of the Flight Safety Foundation in Alexandria, Va., which promotes global airline safety.
The fluid leak identified in the Japanese airline plane was a "very significant finding," said John Goglia, an expert on aircraft maintenance and a former National Transportation Safety Board member.
"There are all kinds of possibilities," Goglia said. "They need to go in and take a look at it. I guarantee you everybody's doing that."
The 787 is the first airliner to make extensive use of lithium-ion batteries to help power its energy-hungry electrical systems. The batteries charge faster and can be better molded to space-saving shapes compared with other airplane batteries.