NTSB Updates Dreamliner Probe, Moves Beyond Batteries

By Paul Riegler on 2 February 2013
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NTSB investigators and Boeing engineers in Seattle

NTSB investigators and Boeing engineers in Seattle

The National Transportation Safety Board and Japanese authorities announced on Friday that they had not found enough evidence in the remains of the two Boeing 787 Dreamliner batteries they are testing to make a determination as to what caused them to over heat. As a result, they are expanding the current probe to include other electrical components.  Testing of the two batteries will continue and one test scheduled for next week will involve shorting out the batteries cells to see if the problem is in the actual cells.

Earlier in the week, both United Airlines and All Nippon Airways, the first operator of the Dreamliner, said that they had had to replace multiple batteries on their 787s because they were wearing out sooner than expected.  United, which received six Dreamliners in September of last year, has replaced three batteries thus far; ANA, which has 17 Dreamliners in its fleet, has replaced ten in the period from May to December.  All three of United’s batteries and half of ANA’s had low power levels upon replacement.

Investigators will try to locate and examine the batteries that were replaced, including other batteries from other airlines where similar replacements took place, to look for clues that could shed light on the problems that led to the January 16, 2013 worldwide grounding of all 50 Dreamliners that were in service.

The NTSB also said it was sending an investigator to France to test components that connect the battery to the airplane’s wiring.  In late January, investigators inspected GS Yuasa’s manufacturing plants in Arizona and Japan.  The battery charger and a controller are made in Arizona, while the battery’s monitoring unit (as well as the battery itself) is made in Japan.  It is also reaching out to others with greater expertise in the area of lithium-ion batteries, including the Naval Surface Warfare Center.

In its seventh report on the situation, the NTSB said it was still performing tests on the battery that had ignited on a Japan Airlines 787 that was at Boston’s Logan International Airport on January 7.  That fire, which occurred when the aircraft was parked and with no passengers on board, followed by a fire on an ANA Dreamliner on January 16, led to the decision to ground the fleetThe Boeing 787 Dreamliner is the first commercial aircraft to use large lithium-ion batteries and it uses five times the amount of electricity in flight as older aircraft, something that contributes to the airplane’s greater fuel efficiency.  If Boeing were required to redesign the batteries, the grounding could last for many months since the more powerful lithium-ion batteries are integral to the aircraft’s design and cannot be replaced but less powerful ones

 

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