US NTSB investigation updates on Japan Airlines Boeing 787 fire at Boston

The National Transportation Safety Board released the fourth update on its on-going investigation into the January 7th fire aboard a Japan Airlines (JAL) Boeing 787, registration JA829J, at Logan International Airport in Boston, USA. The fire occurred after the airplane had landed and no passengers or crew were on-board.

The burnt APU battery unit

The agency has still not found anything untoward and is unable to determine a cause for the auxiliary power unit (APU) battery fire.

In Arizona, investigators have completed testing of the APU start power unit at Securaplane in Tucson and the APU controller at UTC Aerospace Systems in Phoenix. Both units operated normally with no significant findings.

On the left is a photo of the burned auxiliary power unit battery from the JAL Boeing 787. The dimensions of the battery are 19×13.2×10.2 inches and it weighs approximately 63 pounds when new.

JA829J was delivered to JAL on December 20, 2012. At the time of the battery fire, the aircraft had logged 169 flight hours with 22 cycles. The auxiliary power unit battery was manufactured by GS Yuasa in September 2012.

NTSB investigators have continued disassembling the internal components of the APU battery in its Materials Laboratory in Washington, and disassembly of the last of eight cells has begun. Examinations of the cell elements with a scanning-electron microscope and energy-dispersive spectroscopy are ongoing.

A cursory comparative exam has been conducted on the undamaged main battery. No obvious anomalies were found. More detailed examination will be conducted as the main battery undergoes a thorough tear down and test sequence series of non-destructive examinations.

NTSB Investigator Mike Bauer inside the Boeing 787 under investigation at Boston’s Logan Airport

In addition to the activities at the NTSB lab, members of the investigative team continue working in Seattle, and Japan.

Two additional NTSB investigators were sent to Seattle to take part in FAA’s comprehensive review. One of the investigators will focus on testing efforts associated with Boeing’s root cause corrective action efforts, which FAA is helping to lead. The other will take part in the FAA’s ongoing review of the battery and battery system special conditions compliance documentation.

In Japan, the NTSB-led team completed component examination of the JAL APU battery monitoring unit at Kanto Aircraft Instrument Company, Ltd., in Fujisawa, Kanagawa, Japan. The team cleaned and examined both battery monitoring unit circuit boards, which were housed in the APU battery case. The circuit boards were damaged, which limited the information that could be obtained from tests, however the team found no significant discoveries.

Additional information on the NTSB’s investigation of the Japan Airlines B-787 battery fire in Boston can be found at the NTSB incident website.

About Devesh Agarwal

A electronics and automotive product management, marketing and branding expert, he was awarded a silver medal at the Lockheed Martin innovation competition 2010. He is ranked 6th on Mashable's list of aviation pros on Twitter and in addition to Bangalore Aviation, he has contributed to leading publications like Aviation Week, Conde Nast Traveller India, The Economic Times, and The Mint (a Wall Street Journal content partner). He remains a frequent flier and shares the good, the bad, and the ugly about the Indian aviation industry without fear or favour.

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