Japan probe suspects excess voltage in Boeing 787 battery

[indian_foxhound]

TOKYO – The burned insides of a battery in the Boeing 787 at the center of a worldwide
grounding of the aircraft indicate it operated at a
voltage above its design limit, a Japanese
investigator said Friday, as U.S. officials joined
Japan's probe into the incident. The All Nippon Airways plane made an
emergency landing Wednesday morning in
western Japan after its pilots smelled something
burning and received a cockpit warning of
battery problems. Nearly all 50 of the 787s in use
around the world have since been grounded. Photos provided by the Japan Transport Safety
Board of the lithium ion battery that was located
beneath the 787's cockpit show a blackened
mass of wires and other components within a
distorted blue casing. Japan transport ministry investigator Hideyo
Kosugi said the state of the battery indicated
"voltage exceeding the design limit was applied"
to it. He said the similarity of the burned insides of the
battery from the ANA flight to the battery in a
Japan Airlines 787 that caught fire Jan. 7 while
the jet was parked at Boston's Logan
International Airport suggested a common cause. "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. The 787 relies more than any other modern
airliner on electrical signals to help power nearly
everything the plane does. It's also the first
Boeing plane to use rechargeable lithium-ion
batteries for its main electrical system. Such
batteries are prone to overheating and have additional safeguards installed that are meant to
control the problem and prevent fires. GS Yuasa Corp., the maker of the lithium-ion
batteries used in the 787s, said Thursday it was
helping with the investigation but that the cause
of the problem was unclear. It said the problem
could be the battery, the power source or the
electronics system. U.S. safety officials and Boeing inspectors joined
the Japan Transport Safety Board investigation
Friday. The American investigators -- one each from the
Federal Aviation Administration and the National
Transportation Safety Board and two from
Boeing Co. -- inspected the ANA jet on the tarmac
at Takamatsu airport in western Japan. An initial inspection by Japanese officials of the
787 found that a flammable battery fluid known
as electrolyte had leaked from the plane's main
lithium-ion battery beneath the cockpit. It also
found burn marks around the battery. Aviation authorities in Japan have directed ANA,
which owns 17 of the planes, and Japan Airlines,
with seven, not to fly the jets until questions over
their safety have been resolved. The 787, known as the Dreamliner, is Boeing's
newest jet, and the company is counting heavily
on its success. Since its launch after delays of
more than three years, the plane has been
plagued by a series of problems. The FAA has required U.S. carriers to stop flying
787s until the batteries are demonstrated to be
safe. United Airlines has six of the jets and is the
only U.S. carrier flying the model. Aviation authorities in other countries usually
follow the lead of the country where the
manufacturer is based.

 

[indian_foxhound]

burnt battery of boeing 787