NTSB’s 787 Findings May Lead to Boeing Battery Redesign
Evidence is mounting that Boeing Co. may have to redesign the battery on its grounded 787 Dreamliner as U.S. National Transportation Safety Board experts pursue the cause of a Boston jet fire last month.
NTSB Chairman Deborah Hersman yesterday said U.S. regulators’ assumptions in certifying the 787’s lithium-ion batteries “must be reconsidered” after investigators found a short-circuit in one cell set off a chain reaction that destroyed the unit.
What’s known so far suggests Boeing will have to come up with a new design, John Hansman, an aeronautics professor at the Massachusetts Institute of Technology, said in an interview.
“They weren’t supposed to have a fire, and they had a fire, so something went wrong,” Hansman said. “By doing it this way, the NTSB has forced Boeing to do something significant, to prove that they’re doing something different with the battery.”
The U.S. Federal Aviation Administration yesterday said Boeing can conduct test flights to speed efforts toward resolving the battery faults.
Investigators and Boeing are probing the causes of a fire in a Japan Airlines Co. Dreamliner in Boston and a cockpit battery warning, along with the smell of smoke, that spurred an emergency landing in Japan by an All Nippon Airways Co. 787. Those incidents triggered orders by the FAA and foreign regulators starting Jan. 16 that grounded all 50 Dreamliners in service worldwide.
The safety board is “basically calling out the very premise upon which the system was certified,” said Carter Leake, a BB&T Capital Markets analyst in Richmond, Virginia, who is also a former pilot and previously worked for Canadian planemaker Bombardier Inc.
“Getting to a root cause to me seems to be a non-event until we find out what the FAA plans to do with regards to its original certification,” he said. “So I think it’s a very difficult situation that’s opening up here. I think the share gain is a misread of the dynamics here.”
Boeing rose $1.14 yesterday to $77.43, the highest closing price since Jan. 4, the last day of trading before the Boston fire.
That Jan. 7 incident started when a short-circuit in one of the battery’s eight cells set off uncontrolled overheating that spread to the rest of the battery, Hersman said. Boeing had said its pre-certification tests showed no sign such a cascading failure was possible, she said.
Boeing had told the FAA the lithium-ion batteries would produce smoke less than once in 10 million flight hours, Hersman said. Fire or smoke in two planes after fewer than 100,000 flight hours by the 787 raise questions about assumptions used to certify the battery’s safety, she said.
NTSB investigators are looking at possible causes of the initial short-circuit, including the recharging process, contamination in folds within the cell, the battery design and the manufacturing process, Hersman said.
Investigators ruled out mechanical damage and external short-circuiting as a cause of the Boston fire, Hersman said. All battery damage occurred after the short-circuiting began, she said.
The lithium battery packs are an essential component in the design of the Dreamliner, which entered service in 2011. The 787, developed to conserve fuel, uses five times more electricity than similar jets and its fuselage and wings are made from composite materials that are lighter than aluminum.
Because FAA regulations didn’t cover aspects of the new design, the plane was certified with “special conditions” that allowed use of the lithium-ion batteries, Hersman said.
Boeing received regulators’ permission to use the batteries in 2007, three years after the FAA barred passenger planes from carrying non-rechargeable versions of that type of battery as cargo because of fire concerns.
Boeing’s chief engineer, Mike Sinnett, said Jan. 9 that the batteries were designed so that failure of one cell wouldn’t cascade to the others, and that the plane would be safe even if it did. He said there had been no issues with the battery cells over 1.3 million operating hours.
The FAA hasn’t finished its probe of the Dreamliner’s certification and manufacturing processes or reached conclusions about what changes may be needed, U.S. Transportation Secretary Ray LaHood and FAA Administrator Michael Huerta said in a joint statement yesterday.
“We are working diligently with Boeing to figure out the problem and to find a solution,” Huerta said in prepared remarks for a speech yesterday in Salt Lake City. “Our goal is to get this done as quickly as possible, but we must be confident that the problems are corrected before we can move forward.”
The test flights authorized by the FAA yesterday will be subject to restrictions, including that they be conducted over unpopulated areas. Boeing, whose widebody-jet factory is just north of Seattle, said the flights will be above the U.S. Northwest using the fifth of six test jets that were built.
“We are working collaboratively to address questions about our testing and compliance with certification standards, and we will not hesitate to make changes that lead to improved testing processes and products,” Marc Birtel, a spokesman at Boeing’s commercial headquarters in Seattle, said yesterday in a statement.
The agency allowed Boeing to make one ferry flight with a Dreamliner yesterday, under the condition that only the crew would be on board, that special checks of the battery and system would be performed, and that the aircraft would land immediately if there were any indications of a battery fault.
The plane landed in Everett, Washington, after an “uneventful” flight, said Birtel, the Boeing spokesman. No tests were conducted on that trip.
Redesigning the battery wouldn’t necessarily leave the 787 fleet grounded for months, said Hans Weber, chief executive officer of Tecop International Inc., a San Diego-based aerospace consulting company.
While investigating rudder anomolies on the Boeing 737 after two crashes in the mid-1990s, the planemaker and the FAA agreed on temporary fixes that kept the plane flying, Weber said.
“Sometimes it takes years before they find the answer, but that doesn’t mean the fleet has to remain grounded,” Weber said.
To contact the editor responsible for this story: Bernard Kohn at firstname.lastname@example.org