Says Planemaker Did Not Inform Investigators About What It Intended To Say

The NTSB is reportedly unhappy with Boeing officials over the planemaker's March 15 briefing held in Japan outlining plans to get the airplane flying again.

In a letter dated Thursday, NTSB General Counsel David Tochen told Boeing officials that the plans discussed at the briefing were "inconsistent with our expectations" about the potential fix, and that Boeing did not inform the board what it intended to tell investors and others in Japan.

Bloomberg News reports that comments from Boeing executives appeared to be inconsistent with the public positions taken by the NTSB on the issue. In particular, Mike Sinnett, the chief project engineer for the Dreamliner said there had been no "thermal runaway" in the battery cells as defined by Boeing. The NTSB's report said that the battery fire aboard the JAL 787 in Boston was caused by "thermal runaway."

Sinnett also said there had been no fire inside the battery case, but NTSB spokesman Peter Knudson said that a fire hadn't been ruled out.

The board also took exception to Sinnett's depiction of what happened after the battery fire as the airplane responding to such a condition consistent with its design. He said the damage was limited to the battery and the function of the battery, but "the airplane was not a risk." He admitted that the battery failed, but "the airplane responded exactly as we had designed and intended.”

In January, NTSB chair Deborah A.P. Hersman said that “One of these events alone is serious; two of them in close proximity, especially in an airplane model with only about 100,000 flight hours, underscores the importance of getting to the root cause of these incidents.”

The FAA has signed off on Boeing's plan to re-test the battery system. DOT Secretary Ray LaHood said earlier this month that “(t)his comprehensive series of tests will show us whether the proposed battery improvements will work as designed. We won’t allow the plane to return to service unless we’re satisfied that the new design ensures the safety of the aircraft and its passengers.”

The battery system improvements include a redesign of the internal battery components to minimize initiation of a short circuit within the battery, better insulation of the cells and the addition of a new containment and venting system.

(Image of new battery enclosure provided by Boeing)

FMI: www.boeing.com, www.ntsb.gov