Boeing engineers and federal regulators appear to have vastly underestimated the possibility of a lithium-ion battery fire before the 787 Dreamliner was certified.
An interim report released last week by the National Transportation Safety Board said Boeing engineers believed an incident like the Jan. 7 fire on a Japan Airlines plane at Boston's Logan International Airport had a probability of happening just once in a billion flight hours. So far, the 787 fleet has logged approximately 52,000 hours and has already had two incidents in which batteries were burned.
A fire captain who responded to the Boston fire "reported that the battery was hissing loudly and that liquid was flowing down the sides of the battery case," the NTSB said in its 48-page report. "He heard a 'pop' sound," and smoke began pouring out of the electronics equipment bay. The captain "received a burn on his neck when the battery, in his words, 'exploded.'"
As Bert22306 said, "The Chevy Volt and laptop PC batteries, all examples of Li-Ion batteries, have all suffered from these same symptoms" so obviously the probability of an event is not one in a billion flight hours. Furthermore, aircraft cycle through atmospheric pressure changes, operate in high vibration situations, and have much less tolerance for failure. Why is it that electric car and computer users have a more intuitive grasp of battery failure rates than the battery engineers?
There is a March7 Interim Rport on the NTSB website.
In the news, Boeing plans a raft of modifications to the battery pack and wants to get flying asap. As I understand, the root cause has not been found. This is surely unacceptable. At least one example from aviation history (The Comet) where the root cause of a failure was not understood, "fixes" were implemented, but the plane failed again.
I could imagine that the main problem is not to find a technical solution, but to get a new regulatory approval. I do not believe that Boeing can simply replace the battery type and the authorities say: okay, you can fly again.
Still absolutely no new information. For that matter, no information, since we have never been given anything other than the unlikeliest of fault conditions, all of which have been disproven (such as excessive load and incorrectly designed charging cycles).
We should know tonight at 9 PM EDT what the design fix is. Perhaps that will shed some light.
The Chevy Volt and laptop PC batteries, all examples of Li-Ion batteries, have all suffered from these same symptoms. One would think that an aswer would have been more forthcoming, no?
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