Boeing 787 Battery Fire: Thermal Runaway from a Short-Circuited Cell, Says NTSB

So that's for JAL's battery. No word yet on ANA's. There is no mention of multiple occasions of JAL and ANA exchanging batteries throughout last year.

From ABC News (2/7/2013):

The battery fire that grounded Boeing's Dreamliner back in January was started in one of eight battery cells that make up the lithium-ion battery used to power the plane when all other power sources fail, NTSB investigators said at a news conference today.

The single cell showed signs of short circuiting that led to thermal runaway -- a chemical reaction during which a rising temperature leads to increasingly higher temperatures, and spread to the rest of the battery, the board reported.

The NTSB has ruled out external short circuiting as a cause for the problems.

"Boeing has indicated that these tests that were conducted prior to certification showed no evidence of cell-to-cell propagation or fire in the battery," Deborah Hersman, chairwoman of the NTSB, said today in Washington. "However, our investigative findings with respect to the event battery show that when a short circuit did occur, it resulted in cell-to-cell propagation in a cascading manner and a fire."

...The certification tests by Boeing found that the likelihood of "smoke emission" from one cell and then a spread to other areas would occur in less than one out of every 10-million flight hours. The 787 currently has only 100 thousand flight hours, and already there have been two smoke events -- one resulting in a fire.

...But the NTSB said Boeing failed to mitigate the hazards and must review not only the battery problem but its testing that provided false conclusions.

(Full article at the link)

It looks like both Boeing and GS Yuasa have some explaining to do, but to say the "testing ... provided false conclusions" is a bit harsh. As Boeing says, in the article:

"We provided testing and analysis in support of the requirements of the FAA special conditions associated with the use of lithium ion batteries..."

In other words, Boeing provided exactly what the regulator wanted.

(Sound familiar?)

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NTSB Chief Deborah Hersman on Boeing 787 Battery Fire: Plane Batteries Not Necessarily Unsafe

She says NTSB still doesn't have answers why the lithium-ion batteries by Japan's GS Yuasa caught fire in ANA and JAL, but as long as there are safeguards in place we shouldn't worry too much.

(and nuclear reactors that melt down are not necessarily unsafe as long as there are safeguards in place...)

From AP (2/6/2013; emphasis is mine):

NTSB: Plane batteries not necessarily unsafe
NTSB chairman: Lithium batteries not necessarily unsafe in aviation but safeguards needed

WASHINGTON (AP) -- Despite a battery fire in one Boeing 787 Dreamliner and smoke in another, the type of batteries used to power the plane's electrical systems aren't necessarily unsafe — manufacturers just need to build in reliable safeguards, the nation's top aviation safety investigator said Wednesday.

National Transportation Safety Board Chairman Deborah Hersman said she doesn't want to "categorically" rule out the use of lithium ion batteries to power aircraft systems, even though it's clear that safeguards failed in the case of a Japan Airlines 787 that had a battery fire while parked at Boston's Logan International Airport last month.

"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," Hersman told reporters in an interview. 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, Hersman said.

The 787 is the first airliner to make extensive use of lithium batteries. Aircraft makers view lithium 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. Manufacturers are also looking to retrofit existing planes, replacing other types of batteries with lithium ion.

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.

..."What happens is that when an aircraft is certified it basically gets locked into the standards that were in existence at the time," Hersman said. Oftentimes, tougher standards will come along later, but aren't applied to already-approved aircraft designs. "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," she said.

Investigators have been working very closely with the FAA on a review the agency has under way of its sanctioning of the 787's certification for flight, Hersman said. The FAA awarded the certification in August 2011.

"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."

(Full article at the link)

From the article, the issue of safety seems to be just the matter of whether the certification is properly issued by the government bureaucrats. As long as that is properly done, the plane should be safe.

The parallel to things nuclear is obvious.

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Boeing 787 Battery Fire: Short Circuit and Thermal Runaway in One of 8 Battery Cells

From Flight Global (1/24/2013; emphasis is mine):

NTSB finds signs of short circuit, thermal runaway in JAL 787 battery failure

The Boeing 787 battery involved in the Japan Airlines incident on 7 January reveal signs of a short-circuit in one cell and thermal runaway that led to a fire, says the US National Transportation Safety Board.

The NTSB's first press conference 16 days after the JAL battery failure and fire in Boston also revealed that the investigation could still be far from discovering a root cause.

"It is really hard to tell how long the investigation will take," says Deborah Hersman, NTSB chairwoman.

"We have to understand why this battery resulted in a fire when there is so many protections designed into this system," she adds.

The short circuit was found in cell five of the eight-cell, 32V battery that starts the auxiliary power unit and is located in the aft electronic equipment bay in the 787.

But the NTSB has not yet been able to narrow down a set of possible root causes that it is ready to reveal to the public.

"We are seeing symptoms," she says. "We know there is something wrong here. The short circuit, the fire, these are all symptoms that something is wrong."

Hersman says a troubling complication of both the JAL 787 incident and the All Nippon Airways 787 battery event was the timing of the battery failures within 100 flight hours of service by both aircraft.

"We do not expect to see events like what we saw on the 787 in the battery system," Hersman says. "Two battery events in two weeks in the early flights of this aircraft are not what we expect."

The incidents prompted the FAA to order United Airlines to ground all six US-registered 787s on 16 January, an action that triggered a global grounding of the aircraft less than 15 months after it entered service with ANA in October 2011.

So far, the Japan Transport Safety Board and the NTSB have agreed that there is no evidence yet that either battery was over-charged when it failed, but they are continuing to examine the data. Hersman says, for example, that investigators are still considering if it was possible for one of the eight battery cells was over-charged, but not the overall battery.

Another critical part of the investigation is considering the certification process for the 787 batteries.

"These events should not happen as far as design of the airplane," Hersman says. "There are multiple systems to prevent a battery event like this. Those systems did not work. We need to understand why."

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Boeing 787 Dreamliner Battery Fire: NTSB Is Testing Each Battery Cell

NTSB's press release (1/20/2013; emphasis is mine):

NTSB Provides Third Investigative Update on Boeing 787 Battery Fire in Boston
January 20

WASHINGTON - The National Transportation Safety Board today released a third update on its investigation into the Jan. 7 fire aboard a Japan Airlines Boeing 787 at Logan International Airport in Boston.

The lithium-ion battery that powered the auxiliary power unit has been examined in the NTSB Materials Laboratory in Washington. The battery was x-rayed and CT scans were generated of the assembled battery. The investigative team has disassembled the APU battery into its eight individual cells for detailed examination and documentation. Three of the cells were selected for more detailed radiographic examination to view the interior of the cells prior to their disassembly. These cells are in the process now of being disassembled and the cell's internal components are being examined and documented.

Investigators have also examined several other components removed from the airplane, including wire bundles and battery management circuit boards. The team has developed test plans for the various components removed from the aircraft, including the battery management unit (for the APU battery), the APU controller, the battery charger and the start power unit. On Tuesday, the group will convene in Arizona to test and examine the battery charger and download nonvolatile memory from the APU controller. Several other components have been sent for download or examination to Boeing’s facility in Seattle and manufacturer’s facilities in Japan.

Finally, examination of the flight recorder data from the JAL B-787 airplane indicate that the APU battery did not exceed its designed voltage of 32 volts.

In accordance with international investigative treaties, the Japan Transport Safety Board and French Bureau d'Enquêtes et d'Analyses pour la sécurité de l'aviation civile have appointed accredited representatives to this investigation. Similarly, the NTSB has assigned an accredited representative to assist with the JTSB’s investigation of the Jan. 15 battery incident involving an All Nippon Airways B-787. Both investigations remain ongoing.

Further investigative updates on the JAL B-787 incident will be issued as events warrant. To be alerted to any updates or developments, please follow the NTSB on Twitter at www.twitter.com/ntsb.

NTSB Media Contact:
Office of Public Affairs
490 L'Enfant Plaza, SW
Washington, DC 20594
(202) 314-6100
Kelly Nantel
kelly.nantel@ntsb.gov

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