* NTSB will provide some details of probe on Thursday
* Agency thoroughly testing battery that caught fire on jet
* Boeing wants to conduct new test flights
By Doug Palmer
WASHINGTON, Feb 6 The National Transportation
Safety Board is "probably weeks away" from completing its probe
into battery problems on the Boeing 787 Dreamliner, but
will share its latest information on the jet on Thursday, agency
head Deborah Hersman said.
Hersman, who is considered a top candidate to be the next
U.S. transportation secretary, said the agency was doing an
exhaustive examination of a lithium-ion battery that caught fire
in one of the planes and led to the grounding of the Dreamliner.
"We're running through the macro level to the microscopic
level on this battery," she told reporters at a Wednesday
breakfast briefing. "We are going to have some information
tomorrow, but I think we are probably weeks away from being able
to tell people here's what exactly happened and what needs to
All 50 Dreamliners in service have been grounded since Jan.
16 while the NTSB, U.S. Federal Aviation Administration and
other aviation regulators around the world investigate the
battery failures. No root cause has been identified.
The NTSB is looking at both the possible causes of the fire
and the FAA certification process for the Dreamliner.
Hersman said that at Thursday's briefing, "We will talk
about special conditions that were put into effect at the time
when the Dreamliner was certified."
Fire risk on planes has always been a major concern,
especially given the amount of fuel they carry and the heat
generated by jet engines. U.S. aviation standards require planes
to have numerous on-board fire-suppression systems.
The FAA in 2007 granted the Dreamliner special conditions and
said its contain-and-vent system was sufficient to control the
build-up of explosive or toxic gases, except in situations
considered "extremely remote."
That decision has come under scrutiny after the lithium-ion
batteries in two 787 planes failed within days of each other,
sparking a fire in one jet in Boston and generating warnings and
an acrid smell that prompted the pilots of the second plane to
make an emergency landing in Japan.
REQUEST TO CONDUCT TEST FLIGHTS
The NTSB is conducting the U.S. probe with help from Boeing,
battery maker GS Yuasa Corp of Japan, the FAA and
battery experts from other U.S. federal agencies. None of the
agencies have identified what caused the battery failures on the
Boeing this week asked the FAA for permission to conduct new
test flights of the 787, suggesting it is making progress in
finding a solution to the battery problems, but the government
agency has not yet announced a decision.
"In essence what happens when an aircraft is certified, it
basically gets locked into the standards that are in existence
at the time. So the question ... is whether or not as time goes
on through the life of the aircraft, do they fly with new
standards?" Hersman said.
Hersman declined to comment on a report that she was the
White House's top choice to be the next transportation
secretary, saying she was focused on her current job.
Asked what was the most worrisome thing the NTSB had
uncovered so far in its investigation, Hersman referred back to
a finding made public two weeks ago.
"There were short circuits in cells of the battery and there
was thermal runaway in the battery, multiple cells where we saw
uncontrolled chemical chain reactions," she said. "Those
features are not what we expected to see in a brand new battery
and a brand new airplane."
Hersman said the NTSB has been looking at the risks of
lithium-ion batteries for some time and has recommended
strategies to reduce potential hazards.
There will always be advances in technology, but the safety
side of that is "to make sure you've done the right risk
assessment, that you understand what the failure modes are and
that you've mitigated any potential risks," she said.
"I would not want to categorically say that these batteries
are not safe," Hersman said. "Any new technology, any new
design, there are going to be some inherent risks. The important
thing is to mitigate them."