Boeing achieved a major milestone on Tuesday as the Federal Aviation Administration approved its plan to test fixes for the battery problems that have grounded its 787 jets since mid-January.þþBoeing’s new battery design includes better protection in case a battery overheats. The F.A.A. could still demand changes if problems develop in the laboratory and flight tests. While Boeing hopes to begin fitting its redesigned batteries in the grounded 787 fleet by mid- to late April and resume commercial flights quickly after that, government officials are not sure the process will move that fast.þþStill, the decision to start the tests is a big step in Boeing’s efforts to put the innovative jets back in the air. The 50 787s delivered to airlines have been grounded since mid-January after two planes developed battery problems — one battery ignited while the plane was parked in Boston and another forced an emergency landing in Japan when it began to smoke.þþSince then, Boeing engineers have scrambled to insulate the eight cells in each battery, build a sturdier battery case and create a smoke-venting system to quell concerns about the battery’s safety and persuade regulators to lift the grounding order.þþFederal and industry officials said the new plan included fiberglass-like insulation between the battery’s cells to keep a short circuit in one cell from cascading to the others. They said the batteries would be enclosed in stainless steel boxes, more resistant to higher temperatures than the earlier aluminum ones. Boeing also plans to create tubes made of titanium to vent any hazardous gases outside the plane.þþAdding insulation would space the cells farther apart to keep the plane’s vibrations from bringing them into contact. Boeing would also add systems to monitor the temperature and activity in each cell.þþBut the new plan, which calls for 20 tests that would place the battery under stress, could also sharpen a debate among some safety experts over how certain Boeing and the F.A.A. can be that the changes will eliminate the risk of smoke or fire in the batteries. Investigators in the United States and Japan have not been able to determine the precise cause of the battery problems.þþ“This comprehensive series of tests will show us whether the proposed battery improvements will work as designed,” said Ray LaHood, the transportation secretary. “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.”þþThe National Transportation Safety Board has found that in the Boston episode, a short circuit in one cell caused the battery to overheat and burst into flame on Jan. 7.þþBut investigators in Japan have raised the possibility that a battery on another 787 nine days later started smoldering because it might have been hit by a surge of electrical current from another part of the plane.þþJay F. Whitacre, an associate professor of materials science and engineering at Carnegie Mellon University, said Boeing’s approach was technically reasonable even if the cause of the battery fire was not known. Boeing’s system, he said, was designed to contain any failure of a single cell and prevent it from spreading to the rest of the plane.þþ“They are taking a systemic approach, and not a find-the-problem approach,” he said. “They also recognize that figuring out what went wrong is a very complicated question, like a crime scene investigation. Meanwhile, they are focused on getting the planes back in the air.”þþBut not everyone was comfortable with this approach.þþ“I think the real issue here is to develop a robust storage system that is immune to fire,” said Donald R. Sadoway, a materials chemistry professor at M.I.T. “I am not hearing anything about how to make that battery fire-resistant.”þþThe long-awaited announcement by the F.A.A. helped propel Boeing’s stock on Tuesday to $84.16, a five-year high. The confidence of investors was also buoyed by earlier reports of a $15 billion order by Ryanair for 170 single-aisle 737s and Boeing’s decision to move forward with a new version of its best-selling twin-aisle 777.þþThe certification plan requires a series of tests that must be passed before the 787 can return to service. The plan establishes specific pass-fail criteria, defines what should be measured, prescribes test methods and specifies the test setup and design. F.A.A. engineers will be present for the testing and involved in all aspects of the process.þþFederal and industry officials said the tests would subject the battery to the most extreme conditions it was likely to face and determine if the case could withstand a battery explosion. The tests will include bursts of power to put stress on the battery and check its flammability as well as how it performs in hot weather.þþThe F.A.A. has also approved limited test flights for two aircraft. One plane will test the old battery, while the other will test how the new system performs under normal flight conditions. The flight tests will begin within a week.þþThe agency will approve the redesign only if the company successfully completes all required tests and analyses.þþThe F.A.A. said it was continuing a review of the 787’s design, production and manufacturing.þþ“We are confident the plan we approved today includes all the right elements to conduct a comprehensive evaluation of the battery system redesign,” said Michael P. Huerta, the F.A.A. administrator. “Today’s announcement starts a testing process, which will demonstrate whether the proposed fix will work as designed.”þþMr. LaHood said in January that the planes “won’t fly until we’re 1,000 percent sure they are safe to fly.”þþBoeing officials said they thought they had identified the most likely ways in which the batteries could fail. They contend that the changes will virtually eliminate the chances of future troubles and protect the plane and its passengers if a problem does arise.þþBoeing said it would also require its Japanese battery maker, GS Yuasa, to improve its quality control procedures to guard against possible manufacturing defects.þþAviation analysts said the plan would probably protect against the main problem that the safety board identified, a short circuit in one cell that can set off a chemical reaction, causing the battery to overheat.þþBut some battery experts said they would feel more comfortable if a precise cause were found and the problems that happened on the two flights in January could be replicated in a lab.þþ“The tests have to be comprehensive insofar that they capture the conditions that started these fires,” Professor Sadoway said. “How is it that Boeing managed to log more than 50,000 flight hours on the 787 and didn’t manage to turn up any of the problems we are seeing today?”þþApproval of the changes is a highly political process. Mr. Huerta and Mr. LaHood are trying to balance safety concerns with the interest at Boeing and in the airline industry in getting the planes flying again.þþBoeing said the new test plans were based partly on guidelines from the RTCA, an advisory group that provides recommendations on ways to meet regulatory requirements. The guidelines were published in 2008, about six months after the F.A.A. approved Boeing’s original battery plans.þþPerceptions of the traveling public also loom large as Boeing tries to restore confidence in the 787, known as the Dreamliner for its use of new technologies that reduce fuel costs by 20 percent.þþ“It is not inappropriate to test that containment case,” said George W. Hamlin, an aviation consultant, “but until we know more why the fire occurred, simply proving the containment mechanism works doesn’t necessarily imply the airplane should be flying immediately. It’s necessary but not sufficient.”
Source: NY Times
