The officials said Boeing has narrowed down the ways the lithium-ion batteries on the jetliners could fail, and believes that adding insulation between the cells of the batteries and making other changes would provide enough assurance that they would be safe to use.
Raymond L. Conner, the president of Boeing’s commercial airplane division, plans to propose the fixes in a Friday meeting with Michael P. Huerta, the head of the Federal Aviation Administration. Mr. Huerta is not expected to approve the changes immediately, but the meeting is likely to start a high-level discussion on the standards Boeing needs to meet as it tests the fixes and seeks to get the planes flying again.
Boeing’s plan could be a pivotal moment in the history of the innovative fuel-efficient planes. Mr. Huerta and regulators around the world grounded the planes in mid-January after a battery caught fire on one jet parked at the Boston airport and smoke forced another 787 to make an emergency landing in Japan.
Investigators have not determined what caused those problems. But Boeing’s engineers have worked closely with the F.A.A. and outside experts to identify ways in which the batteries could have failed, and Boeing is now asking the government to sign off on a calculation that they have now come up with a safer design.
Given the risks in moving ahead, federal officials said, the F.A.A. has insisted behind the scenes that Boeing needed to come up with changes to prevent failures at the same time as it proposed further steps to wall off problems with the batteries and vent any smoke or fire outside the planes.
Boeing officials said they had also hoped to make all the fixes at once rather than dividing them into temporary and longer-term changes. By delaying some changes, Boeing could have been exposed to more problems.
As a result, one big change under Boeing’s plan would be to redesign the batteries to place insulation inside and around each of the eight cells to minimize the risk that a short circuit or fire in one of the cells could spread to the others, as investigators have said occurred on the battery that caught fire in Boston on Jan. 7. Boeing might also adjust how tightly the batteries are packed.
Boeing would make other changes within the batteries to reduce the chance that vibrations, swelling or moisture could cause problems, industry officials said. Boeing has already been testing some of the changes. The plane maker believes it could rebuild the batteries by next month on the 50 jets that have been delivered to airlines. But federal officials are likely to move more slowly and demand more tests and assurances, and the final decision could rest with Mr. Huerta’s supervisors at the Transportation Department.
Federal officials said that if the fixes check out, the jets could start flying again by April. Boeing will also have to win back the confidence of the flying public.
Besides taking more steps to prevent short circuits from occurring, Boeing’s plan would enclose the battery within a sturdier metal container and create tubes to vent any hazardous materials outside the plane. It would add systems to monitor the activity inside each cell instead of just the battery as a whole.
Industry officials said there is enough space in the electronics bay to expand the container and add the vent tubes.
Until now, regulators have focused on the need to pin down the cause of the battery problems. But investigators, now weeks into their work, have been able to find only limited clues in the charred remains of the batteries in the Boston and Japan incidents.
The lithium-ion batteries weigh less but provide more energy than conventional batteries, and the 787s make greater use of them than other planes. The stakes are substantial for Boeing, which will have to pay penalties to some of the airlines that have been unable to use them. Boeing also cannot deliver more of the planes while they are grounded.
The company has orders for 800 additional planes. The jets rely as well on lightweight carbon composites and more efficient engines.
Boeing awarded the contract for the batteries to GS Yuasa, a Japanese firm, in 2005, and it won approval from the F.A.A. to use the batteries in 2007. Concerned about fires with smaller lithium-ion batteries in cellphones and laptops, the agency placed special conditions on Boeing’s use of the batteries that required containment and venting measures that have proved inadequate.
Advances in research have contributed to a better understanding of the risks since then. But Boeing, which was consumed with problems with other parts that delayed the introduction of the 787s by several years, did not significantly update the battery designs before it began delivering the planes in 2011. So Boeing’s plan to fix the problems also amounts to a belated incorporation of what has been learned about how to handle the risks.
Article source: http://www.nytimes.com/2013/02/21/business/boeing-to-propose-battery-fixes-to-faa.html?partner=rss&emc=rss