March 29, 2024

Safety Board Reports Little Progress in 787 Inquiry

The report reiterated statements by Deborah Hersman, the board’s chairwoman, who told reporters last month that the problems seemed to have originated in the battery, when one of the eight cells had a short circuit and the fire spread to the rest of the cells.

While the safety board plans to continue its investigation, it said it would also hold a hearing on the hazards of the new lithium-ion batteries next month.

Meanwhile, federal officials said Wednesday that the Federal Aviation Administration was close to approving tests of Boeing’s approach to fixing the batteries on its 787 jets, and the tests could begin next week.

Boeing officials said they had identified the most likely ways in which the batteries could fail. They contend that the changes would minimize the odds of future incidents and protect the plane and its passengers if a problem does arise.

The F.A.A. could still demand changes in Boeing’s proposed new battery design if problems develop in the laboratory and flight tests, which will take several weeks. But the decision to start the tests will be a major step in Boeing’s efforts to get the jets, which have been grounded since mid-January, back in the air.

The federal approvals are expected late this week or early next week, even though some battery specialists remain concerned that investigators have not found the precise cause of two incidents in which the jetliner’s new lithium-ion batteries emitted smoke or fire.

The plan is still subject to approval by Michael P. Huerta, the head of the F.A.A., and Ray LaHood, the transportation secretary, who will be briefed on it over the next several days.

Mr. LaHood said in January that the planes “won’t fly until we’re 1,000 percent sure they are safe to fly.” Department officials said Mr. LaHood and Mr. Huerta had been kept informed of the details of the proposal as it was created, and they are expected to sign off on it.

Under the plan, Boeing proposed adding insulation among the eight cells in the battery to minimize the risk of a short-circuit cascading through most or all of them. The company also proposed adding systems to monitor the temperature and activity in each cell. It would enclose the batteries in sturdier steel boxes to contain any fire, and it would create tubes to vent hazardous gases outside the plane.

The 787 is the first commercial airplane to use large lithium-ion batteries for major flight functions.

Boeing has delivered 50 787s to eight airlines, and officials said it could install new batteries in them quickly once a new design was approved. The company has much at stake with the plane, which is the first commercial jet to be built mostly out of lightweight composite materials. Boeing has orders for 800 more of the planes.

Aviation analysts said the plan would probably protect against the main problem that the safety board has identified, a short-circuit in one of the cells that can trigger a chemical reaction that leads the battery to overheat.

But investigators in Japan have suggested that something else may have caused the battery on an All Nippon Airways 787 to emit smoke on a flight on Jan. 16. They said the battery may have been hit by a surge of electrical current from another part of the plane.

Donald R. Sadoway, a professor of materials chemistry at the Massachusetts Institute of Technology, said the Japanese data suggested that temperatures might have shot much higher in that battery than in the one on the plane in Boston. If that is true, he said, Boeing and the F.A.A. might need to add more steps to the safety plan to guard against such possibilities.

The safety board is also looking into how the F.A.A. certified the plane and the batteries as safe in 2007 when Boeing’s design and testing then were clearly deficient.

Ms. Hersman said last month that Boeing’s original tests showed no indication the batteries could erupt in flame and concluded that they were likely to emit smoke less than once in every 10 million flight hours.

Once the planes were placed in service, though, the batteries overheated and emitted smoke twice, and caused one fire, after about 50,000 hours of commercial flights.

Raymond L. Conner, the president of Boeing’s commercial airplane division, said this week that industry and academic researchers had learned much since then about the volatile batteries. Other company officials said Boeing would also incorporate what it learned from the two recent incidents into its new tests.

Article source: http://www.nytimes.com/2013/03/08/business/safety-board-reports-little-progress-in-787-inquiry.html?partner=rss&emc=rss

Speak Your Mind