Is the NTSB chairman jumping the gun?

The Japan Airlines Boeing 787 lithium ion battery that caught fire in Boston Jan. 7 experienced “a thermal runaway” and “short circuits,” the US National Transportation Safety Board (NTSB) reported.

NTSB chairman Deborah Hersman, briefing reporters in Washington DC on Thursday, said no cause for the fire has been determined, and indicated NTSB may still need some time to find the root cause.
She described thermal runaway as “uncontrolled chemical reactions” within the battery’s cells. The battery is used to start the aircraft’s auxiliary power unit (APU). “The APU battery was spilling molten electrolytes,” she said.

Hersman expressed serious concern about the JAL 787 fire and what she characterized as the All Nippon Airways 787 “smoke event” that occurred Jan. 16. The ANA incident, which led to an emergency landing, is also linked to a damaged lithium ion battery.

Having two battery failures causing fire and/or smoke aboard a new aircraft type within such a short period “is an unprecedented event. We are very concerned,” she commented. “This is a very serious air safety concern.”

Hersman said, “The expectation in aviation is never to experience a fire aboard an aircraft … The significance of these two events cannot be overstated … These events should not happen as far as the design of the aircraft. There are multiple systems that are in place to prevent [a battery failure from escalating to a serious event]. Those systems did not work.”

She emphasized that FAA, not NTSB, will decide if and when to lift the worldwide grounding of Dreamliners. But she indicated NTSB’s investigation into the JAL 787 fire may take some time.

“We have to understand why this battery failure resulted in a fire when there were so many protections designed into the system,” she said. “There’s a lot more work to do … We are conducting a forensic investigation … It is really very hard at this point to tell how long the investigation will take. What I can tell you is that we have all hands on deck … This is not something we’re expecting will be resolved overnight … We are prepared to do the methodical work that gets to the root cause of this. We have not yet identified the sequence of events that initiated the short circuits or the thermal runaway.”

(Aaron Karp - ATWOnline News)