To get its 787 Dreamliner flying again, Boeing Co. is testing the plane’s volatile battery system to a rigorous standard that the company itself helped develop – but that it never used on the jet.
Boeing’s decision has thrust an arcane standard known as RTCA to the centre of the debate over whether Boeing and the U.S. Federal Aviation Administration (FAA) were rigorous enough when they originally set standards for the 787 battery system in October 2007. The debate could have broad implications for the future use of lithium-ion batteries on aircraft.
A committee co-chaired by Boeing published safety guidelines in March 2008 for using lithium-ion batteries on aircraft to minimize the risk of fire. But because they arrived five months after the FAA had approved a set of special conditions for the fire safety of the Dreamliner battery system, Boeing did not have to meet the more stringent guidelines. The FAA never required it, and Boeing did not choose to use them.
Last week, Boeing decided to shift to the tougher RTCA standard for a revamped 787 battery system. The move came after regulators grounded Dreamliners worldwide in January following a battery fire on a Japan Airlines Co. 787 at Boston’s Logan Airport and a battery meltdown on an All Nippon Airways Co. flight in Japan.
Some battery industry experts voiced surprise that Boeing did not apply the RTCA standard when it was published in 2008. Even though the tests were not required, they would have served as a check on Boeing’s design assumptions and possibly prevented the battery from overheating in January, they said.
John Goglia, a former board member of the National Transportation Safety Board (NTSB), said he sees the use of the RTCA standard “as an admission that they didn’t do a good job in the beginning.”
“It is going to be part of the final NTSB report,” he added. “It will be at least mentioned in there.”
The NTSB last month questioned the assumptions Boeing and the FAA made when certifying the battery system in 2007. The safety agency plans to hold a hearing on the issue next month and is expected to recommend changes to FAA procedures after completing its investigation into the battery failures.
Boeing spokesman Marc Birtel said Boeing did not use the RTCA standard earlier because it came “after we had completed our certification plans and begun our testing efforts.”
Under the special conditions, the Dreamliner passed “a rigorous test program and an extensive certification program conducted by the U.S. Federal Aviation Administration,” he said.
The RTCA test will be used on an extensive new battery system Boeing unveiled on Friday. It adds safeguards to prevent fire, keep fumes from entering the cabin and ensure the jet’s ability to fly and land are never compromised.
Boeing said it already is about one-third through testing with the tougher RTCA regimen, known as “DO-311” and is likely to finish “within a week or two.”
Asked why Boeing had not used the RTCA standard, a senior Boeing engineer on Friday suggested the standard was too broad.
The RTCA standard “covered a wide range of lithium-ion batteries and it contained roughly 104 requirements,” said Ron Hinderberger, vice-president of 787-8 engineering. “Some of those requirements went beyond the requirements that were established in the special condition.”
The FAA did not respond to questions on why it did not apply the standard earlier or Boeing’s decision to use it now. The FAA adopted the standard in April 2011.
Richard Lukso, the former head of Securaplane Technologies, the Arizona company that supplied the charging unit for the 787 battery, said Boeing should have asked its battery subcontractor, GS Yuasa Corp. of Japan, to use the RTCA standard. GS Yuasa declined to comment.
“It was (Boeing’s) responsibility to request that test,” Mr. Lukso said.
The RTCA, formed in 1935 as the Radio Technical Commission for Aeronautics, is a private, not-for-profit industry group whose policy recommendations are often used by the FAA. Its battery committee – whose members included employees from Boeing’s battery maker GS Yuasa, the battery system maker Thales SA of France and the FAA – drafted a 68-page document to set “minimum operational performance standards” for rechargeable lithium-ion batteries used as power sources on planes.
These guidelines “are generic in nature,” the committee said, “and serve only as a baseline for the design and test of specific battery systems and equipment pairings.”
The document included clearer and more specific tests than the FAA set, along with tougher standards. For example, the 787 special conditions say Boeing’s battery system must prevent “explosive or toxic gases” from accumulating in “hazardous quantities” in the airplane in any situation that is not “extremely remote.” In FAA parlance, “extremely remote” means once in 10 million flight hours.
But the DO-311 standards say the tests must show the chances are “extremely improbable” – FAA code for one in a billion flight hours.
Boeing’s tests, which included puncturing the battery with a nail and subjecting it to heat, predicted the chance of a fire was less than one in 10 million flight hours. But when the plane was in use, two batteries overheated and emitted smoke and fumes after less than 100,000 hours, according to the NTSB.
Mr. Lukso, who left SecuraPlane to start his own lithium-ion battery business, acknowledged that the RTCA standards are tough. At his new company, he spent $6-million and several years without successfully building a battery that could pass the test now in front of Boeing.
Another battery maker, EaglePicher Technologies, of Joplin, Miss., passed tests modelled on DO-311, but used a less volatile chemistry than Boeing, known as lithium-iron phosphate.
“To successfully pass the containment (test), we needed iron phosphate,” Ron Nowlin, general manager of aerospace systems for EaglePicher, said in an interview earlier this year.