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Dreamliner probe widens after excess battery voltage ruled out(Philips Transducer)
Federal Aviation Administration says released flammable chemicals and could have sparked a fire in the plane's electrical compartment.Philips Transducer National Transportation Safety Board's statement eliminated one possible answer that had been raised by Japanese investigators.

It also underscored the complexity of investigating a battery system that includes manufacturers across the world, and may point to a design problem with the battery that could take longer to fix than swapping out a faulty batch of batteries.

"Examination of the flight recorder data from the JAL B 787 airplane indicates that the APU (auxiliary power unit) battery did not exceed its designed voltage of 32 volts," the NTSB said in a statement issued early Sunday.

On Friday,Toshiba Transducer a Japanese safety official had told reporters that excessive electricity may have overheated the battery in the ANA owned Dreamliner that was forced to make the emergency landing at Japan's Takamatsu airport last week. investigators have already examined the lithium ion battery that powered the APU, where the battery fire started in the JAL plane, as well as several other components removed from the airplane, including wire bundles and battery management circuit boards, the NTSB statement said.

On Tuesday, investigators will convene in Tucson, Arizona to test and examine the charger for the battery, and download non volatile memory from the APU controller, with similar tests planned at the Phoenix facility where the APUs are built. Other components have been sent for download or examination to Boeing's Seattle facility and manufacturer facilities in Japan. investigation.

The NTSB's decision to travel to Securaplane's facility sparked fresh questions about the safety of the lithium ion batteries that remain at the heart of the investigation.

While the 787 is the most aggressive user of lithium ion battery technology in commercial aviation, the industry at large is testing it, and the FAA has approved its use in several different planes, each governed by "special conditions."

"Lithium ion batteries are significantly more susceptible to internal failures that can result in self sustaining increases in temperature and pressure," the FAA said in 2006, when it allowed Airbus to use lithium batteries for the emerging lighting system on its A380.

Securaplane, which first began working on the charger in 2004, suffered millions of dollars of damages in November 2006 after a lithium ion battery used in testing exploded and sparked a fire that burned an administrative building to the ground.

Boeing spokesman Marc Birtel said an investigation into the 2006 fire was later determined to have been caused by an improper test set up, not the battery design. He declined comment on the current 787 investigations.

After the fire, a former Securaplane employee named Michael Leon sued the company, alleging that he was fired for raising security concerns about charger and discrepancies between their assembly documents and the finished chargers.

Leon's suit was later dismissed. Federal Aviation Administration (FAA) on Sunday said it had investigated Leon's safety complaints in 2008 and 2009 but concluded his allegations focused on prototypes that were not ultimately used in the new lightweight airliner.

FAA spokeswoman Laura Brown said the reviews also found that Securaplane's production of a particular printed circuit board complied with FAA requirements. Thales has declined comment. No comment was immediately available from the French safety agency. statement in its probe.

The NTSB said the Japanese agency was participating in its investigation of the Boston incident, while NTSB officials were helping the agency with its investigation of the emergency landing in

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