Overcharged batteries likely to blame in Boeing 787 fires

It's likely that burning lithium ion batteries on two Boeing 787 Dreamliners were caused by overcharging, aviation safety and battery experts have said, pointing to developments in the investigation of the Boeing incidents as well as a battery fire in a business jet more than a year ago.

An investigator in Japan, where a 787 made an emergency landing earlier this week, said Friday the charred insides of the plane's lithium ion battery show the battery received voltage in excess of its design limits.

The similarity of the burned battery from the All Nippon Airways flight to the burned battery in a Japan Airlines 787 that caught fire Jan. 7 while the jet was parked at Boston's Logan International Airport suggests a common cause, Japan transport ministry investigator Hideyo Kosugi said.

"If we compare data from the latest case here and that in the U.S., we can pretty much figure out what happened," Kosugi said.

In the case of the 787 in Boston, the battery in the plane's auxiliary power unit had recently received a large demand on its power and was in the process of charging when the fire ignited, a source familiar with the investigation of the 787 fire in Boston told The Associated Press. The plane had landed a short time earlier and was empty of passengers, although a cleaning crew was working in the plane.

The source spoke on condition of anonymity because he wasn't authorized to speak publicly.

Info: cbc.ca