B787 - Batteriet var ikke overladet, noe som fører til ytterligere systemsjekk

NTSB Finding Adds Wrinkle to 787 Battery Probe

AIN AIR TRANSPORT PERSPECTIVE » JANUARY 21, 2013

by  GREGORY POLEK

Excess voltage did not cause the APU battery on a Japan Air Lines Boeing 787 to catch fire, according to the NTSB. (Photo: NTSB)

January 21, 2013, 12:55 PM

Data from the flight recorder retrieved from theJapan Air Lines Boeing 787 that caught fire on January 7 while parked at Boston Logan International Airport shows that the airplane’sAPU battery did not charge beyond its design limit of 32 volts, according to the U.S. National Transportation Safety Board. Investigators have disassembled the lithium-ion battery in question, an eight-cell unit made by Japan’s GSYuasa, in an effort to help determine the cause of the first of two separate battery failures that led to the grounding of all 50 Dreamliners Boeing has delivered to seven airlines around the world. Japanese authorities have yet to determine whether or not the battery failure that forced an emergency landing of an All Nippon Airways 787 in western Japan last Wednesday had overcharged as widely reported. That incident prompted both ANA and JAL to ground their 787s, and preceded a mandated suspension of Dreamliner service in the U.S. and around the globe.

NTSB investigators have also examined several other components removed from the JALairplane, including wire bundles and battery management circuit boards. The team has developed test plans for the various components removed from the aircraft, including the APU battery management unit, the APU controller, the battery charger and the start power unit. The group plans to convene on Tuesday in Arizona to test and examine the battery charger and download nonvolatile memory from the APU controller. The board has also sent several other components for download or examination to Boeing in Seattle and Yuasa facilities in Japan.