Dreamliner Inquiry Questions Safety Approval - lithium ion cell
S. top accident investigators say the US government should reconsider its safety approval for lithium-ion batteries used in Boeing's 787 aircraft.
The findings released on Thursday raised doubts about whether the plane's failure could be resolved quickly.
The National Transportation Safety Commission is investigating a battery fire last month on the 787 "Dreamliner" of Japan Airlines, which stopped at Boston Logan International Airport.
NTSB Chairman Deborah Hersman said the results so far contradict some of the government-approved assumptions about battery safety.
On the same day that the findings were released, the FAA said it would allow Boeing to conduct a test flight at its 787 to collect data on the performance of the aircraft's battery while flying in the air.
It is not clear when these test flights will begin.
The investigation of NTSB found that the fire was caused by multiple short-
One of the eight batteries.
Produced an uncontrolled chemical reaction called "heat out of control"
MS Hersman said the circuit was connected to other units and caused a fire.
Hersman said the finding was inconsistent with what Boeing told the FAA when it flew the FAA certified technology advanced aircraft. MS.
Boeing said the test showed
The circuit will be included in a unit to prevent heat from getting out of control and fire, she said.
"The assumptions used to prove the battery must be reconsidered," MS Hersman said . ".
The Boeing test also showed that the battery could cause only one smoke in 10 million flight hours, she said.
But nine days later, after the Boston fire, there was another smoking battery on an air carrier plane that had to land urgently.
Hersman added that the flight time of the 787 fleet was less than 100,000 hours. MS
The plane that caught fire in Boston was delivered to Japan Airlines less than three weeks before the fire and recorded only 169 flight hours on 22 flights.
The commission's findings appear to raise doubts about the thoroughness of the FAA's safety certification of 78 7 batteries.
FAA relies to some extent on the expertise of the manufacturer's engineers, especially in the case of cutting
Edge plane like 787.
There are also questions about whether Boeing can solve the problem by adding some quick safeguards.
After the Boston fire, U. S. Transportation Secretary Ray LaHood and FAA director Michael Hurta ordered a review of the design, certification, manufacturing and assembly of 78 7.
The review is still in progress.
FAA officials have ordered the only 787.
United Airlines with six airlinesto ground them.
Aviation authorities in other countries quickly followed suit, with a total of 50 aircraft grounded in seven airlines in six countries.