TOKYO/SEATTLE Jan 16 Investigators in Japan are
studying x-ray images of a lithium-ion battery from when it left
the factory, hoping these may shed some light on why it appeared
to overheat on a Boeing 787 Dreamliner jet earlier this week.
They will be looking for possible anomalies in the battery,
which is made by Japanese firm GS Yuasa, and hope this
could also help them resolve two similar battery incidents on
separate 787 planes a year ago.
The battery damaged on a Japan Airlines (JAL)
Dreamliner this week could provide more clues to investigators
if it has survived in better condition than the ones scorched in
incidents on a JAL 787 in Boston last year and on an ANA
Holdings 787 in Japan just a few days later.
GS Yuasa scans the eight-cell batteries with an x-ray-like
system before they are shipped, and the images are checked for a
list of potential problems to ensure the batteries are not
flawed, said John Goglia, a former National Transportation
Safety Board (NTSB) member.
Those images will be used as a basis for looking for other
problems that could have caused the 787 batteries to erupt.
"They'll now go back and examine those to see if there's
anything they missed," Goglia said.
GS Yuasa declined to comment on whether it was looking at
x-rays of the battery cells.
JAL took the 787, one of 13 in its fleet, out of service on
Tuesday after workers preparing the plane for flight spotted
white smoke outside the aircraft. Warning lights indicated a
fault with the battery and its charger, which engineers later
found had leaked liquid from one cell.
No passengers were aboard, but the incident has reignited
concerns over the state-of-the-art 787's safety and reliability,
coming a year after two lithium-ion batteries overheated on
Dreamliners, prompting regulators to ground the global fleet for
more than three months while Boeing revamped the battery,
charger and containment system to improve safety.
Batteries on the 787 are now housed in a redesigned metal
containment box, with insulated separators and special valves to
vent hot gases directly outside the plane.
The Japan Civil Aviation Bureau (JCAB) is heading the search
for what went wrong with the power pack in this week's incident.
GS Yuasa, Boeing and JAL are also involved, as are investigators
from the NTSB in the United States and the Japan Transport
Safety Board (JTSB). Those two agencies have yet to figure out
the cause of last year's battery issues.
The JTSB has no jurisdiction over Tuesday's battery
incident, as it hasn't been logged as an accident, but the
agency hopes to gather fresh data to help its investigation into
last year's ANA incident, a JTSB official told Reuters.
The NTSB said it was sending aircraft systems investigator
Mike Bauer to Japan to assist the JCAB.
In the past year, the global fleet of 787s has more than
doubled to 115 planes operated by 16 carriers. ANA is the
world's leading operator with 24 Dreamliners.
Goglia said engineers, maintenance people and Boeing
employees have told him the latest battery rupture appears so
far to be a single event, rather than a problem that is likely
to repeat itself. He noted Boeing has not issued a service
bulletin to airlines recommending action.
"If they find something in the review process that's a
concern, they would issue a bulletin, but so far there's no
indication of what the root cause of the failure was," he said.
"If they don't know what's wrong, they don't know how to fix
Investigators also are likely to look for a voltage spike or
other abnormality in the data that is gathered by sensors in the
battery system, said Michel Merluzeau, managing partner at G2
Solutions, an aerospace and defense consulting firm in Kirkland,
He and Goglia both noted the containment system had worked
as planned, by stopping the problem from affecting other cells
of the battery, and not damaging the plane.
"I think it's a vindication of the fix," Merluzeau said.
The battery is used to "bring the airplane to life" by
powering its systems before the plane's own gas-powered
generator is started, according to Boeing. The 787 is built with
carbon-fiber composite materials and a powerful electrical
system to reduce weight and improve fuel efficiency.