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NTSB issues 787 battery probe update

By Hpanchal on February 1, 2013

The NTSB issued its seventh update Friday on its investigation into the Jan. 7 fire aboard a Japan Airlines Boeing 787 at Logan International Airport in Boston.

The auxiliary power unit battery, manufactured by GS Yuasa, was the original battery delivered with the airplane on December 20, 2012. It is comprised of eight individual cells. All eight cells came from the same manufacturing lot in July 2012. The battery was assembled in September 2012 and installed on the aircraft on October 15, 2012. It was first charged on October 19, 2012.

In the photo above, NTSB investigators and Boeing engineers in Seattle examine the type of lithium ion battery used on the Boeing 787 to start the auxillary power unit and to provide backup power for flight critical systems.

Examination and testing of an exemplar battery got underway earlier this week at the Carderock Division of the Naval Surface Warfare Center laboratories in West Bethesda, MD. The tests consisted of electrical measurements, mass measurements, and infrared thermal imaging of each cell, with no anomalies noted. The cells are currently undergoing CT scanning to examine their internal condition. In addition, on Thursday, a battery expert from the Department of Energy joined the investigative team to lend his expertise to the ongoing testing and validation work.

An investigative group continued to interpret data from the two digital flight data recorders on the aircraft, and is examining recorded signals to determine if they might yield additional information about the performance of the battery and the operation of the charging system.

Next week, the NTSB battery testing team will initiate a non-invasive "soft short" test of all cells of the exemplar battery. This test will reveal the presence of any high resistance, small or "soft" shorts within a cell. Also, an NTSB investigator will travel to France with the battery contactor from the JAL event battery, for examination at the manufacturer. The battery contactor connects a wiring bundle from the airplane to the battery.

Investigators are continuing their work in Washington and Japan and the team in Seattle continues to observe the FAA-led review of the certification process for the 787 battery system. The flow of information from these observations helps to inform NTSB investigative activity in the US and around the world.

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