Lithium Batteries Are Not Necessarily Unsafe, Safety Board Says

The chairwoman of the National Transportation Safety Board, Deborah Hersman, said she did not want to ”categorically” rule out the use of lithium-ion batteries to power aircraft systems.

Then, referring to the battery fire last month on a Japan Airlines 787 parked at Logan Airport in Boston, Ms. Hersman said, ”Obviously what we saw in the 787 battery fire in Boston shows us there were some risks that were not mitigated, that were not addressed.” The fire was “not what we would have expected to see in a brand-new battery in a brand-new airplane,” she said.

The board is still weeks away from determining the cause of the Jan. 7 battery fire, Ms. Hersman added.

The 787 is the first airliner to make extensive use of lithium-ion batteries. Aircraft makers see the batteries, which are lighter and can store more energy than other types of batteries of an equivalent size, as an important way to save on fuel costs. The Airbus A350, expected to be ready next year, will also make extensive use of lithium-ion batteries. But lithium batteries are more likely to short-circuit and start a fire than other batteries if they are damaged, if there is a manufacturing flaw or if they are exposed to excessive heat.

Investigators are also looking into the special conditions the Federal Aviation Administration imposed on Boeing in 2007 to use the lithium-ion batteries, she said.

“What happens is that when an aircraft is certified it basically gets locked into the standards that were in existence at the time,” Ms. Hersman said. “Those are issues we do look at regularly in our investigations and it is something I’m sure we will be focusing on with the battery.”

Investigators have been working with the F.A.A. on a review of the 787’s certification for flight, Ms. Hersman said.

“We are evaluating assessments that were made, whether or not those assessments were accurate, whether they were complied with and whether more needs to be done,” she said. “I think that is important before this airplane is back in the air, to really understand what the risks are and that they’re mitigated effectively.”

Nine days after the battery fire in Boston, another battery overheated on an All Nippon Airways 787, leading to an emergency landing in Japan. The same day, F.A.A. officials ordered American carriers with 787s — there was only one, United Airlines, with six planes — to ground the planes. Aviation authorities in other countries quickly followed suit. In all, 50 planes operated by seven airlines in six countries are grounded.

Article source: http://www.nytimes.com/2013/02/07/business/lithium-batteries-are-not-necessarily-unsafe-safety-board-says.html?partner=rss&emc=rss