Boeing’s Fix for its Flaming Lithium Batteries: Is There A Fatal Flaw?

dubaiupsplanecrash“Boeing Co. is confident that proposed changes to the 787 Dreamliner will provide a permanent solution to battery problems that grounded its newest jet, a senior executive said Monday.” –Reuters, 11 March 2013

The reported changes include “adding ceramic insulation between the cells of the battery and a stronger stainless steel box with a venting tube to contain a fire and expel fumes from the aircraft.” –Reuters, Alwyn Scott and Tim Hepher and Peter Henderson, 5 Mar 2013

Why is Boeing confident? This is a mystery because, based on available published data, it does not appear that Boeing has positively determined the root cause of the battery fires. Furthermore, as for all safety-critical applications, the certainty of the cause should be determined beyond a reasonable doubt. This stringent requirement would be certified by a panel of independent experts of unquestioned expertise and integrity, who have no financial interest in the outcome of their review.

Without positive identification of the root cause, Boeing may be indulging in a logical fallacy that I have seen employed before, with very bad results. The fallacy is in trying to fix what is assumed to be the problem (e.g. inadequate thermal insulation between battery cells). But what if the assumption is wrong? If so, the “fix” could be ineffective, or even make things worse. For example, improving cell insulation will trap more heat within the cells, raising the cell temperature. If the true root cause is related to higher cell temperature, the added insulation could make cell failure more likely, not less.

There are many other troubling scenarios that can be hypothesized, and the only way to disprove them is to dig in and find the true root cause, beyond a reasonable doubt (including rigorous validation as discussed here: “Flying the Flaming Skies: Should You Trust the Boeing Dreamliner?“)

-Ed Walker

P.S. A good review of the genesis of the Boeing battery problem can be found here: “NTSB report shows Boeing’s battery analysis fell short,” Dominic Gates, Seattle Times

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Posted on March 11, 2013, in Batteries, Failure Analysis, Risk Assessment, Worst Case Analysis and tagged , , , , . Bookmark the permalink. Leave a comment.

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