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Investigators still do not know exactly why there was a battery fire on a Japan Airlines Boeing 787 jet back in January. On the concluding day of a National Transportation Safety Board hearing, officials did conclude that the original tests of the battery were in adequate.
NPR's Wendy Kaufman reports.
WENDY KAUFMAN, BYLINE: The worldwide fleet of Boeing 787s - that has been grounded for three months - will soon be returning to passenger service.
Those jets will have newly designed batteries - housed in a fire proof containment box. There are other safety enhancements too. And one can't help but wonder if some of those features should have been incorporated into Boeing's earlier design of the battery.
But it's not that simple. As NTSB chairman Deborah Hersman noted, the battery failure on the JAL jet - and a second serious battery failure that same month - came as a surprise.
DEBORAH HERSMAN: Those events were not expected by the operators, by Boeing; they were not expected or anticipated by the regulator.
KAUFMAN: Boeing never conducted a test that produced the kinds of failures that occurred on those two jets. And that leads Hersman to conclude...
HERSMAN: We know that those test conditions weren't conservative enough.
KAUFMAN: Boeing's made assumptions about how the battery would behave that don't seem to hold up. But those assumptions drove some of the testing that Boeing did.
In approving the batteries, the FAA relied in large part on Boeing's own data and test results. The agency doesn't have the resources to do their own comprehensive analysis. Still, FAA officials like Steve Boyd insist the agency's fundamental approach to airplane safety is sound.
STEVE BOYD: We try to build whole families of requirements that trap the safety issues.
KAUFMAN: The one thing we cannot do, he said is wait until we know everything about a new technology before we adopt it.
Hersman wouldn't quarrel with that, but suggested that the FAA should have required that Boeing retest its battery using industry standards that came out after regulators had approved the 787 testing requirements. But Boyd told Hersman those tests weren't required then and shouldn't be required now.
BOYD: That typically wouldn't be done only if we identified an unsafe condition.
HERSMAN: Have you identified any unsafe conditions where you would want to modify the expectations for lithium ion battery performance?
KAUFMAN: His answer was, no.
That exchange goes to a central question for the NTSB: Are FAA standards and its certification process flexible enough to adapt to new information and changing technologies?
Insuring flexibility will likely be one of the recommendations that stem from this investigation.
Wendy Kaufman, NPR News, Washington. Transcript provided by NPR, Copyright NPR.