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NTSB: Boeing 787 battery shows short-circuiting

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Updated: February 26, 2013 6:34AM

The end to the grounding of Boeing’s 787 Dreamliner does not appear to be close at hand, according to an update Thursday from the National Transportation Safety Board.

In a new development, the NTSB investigation has turned up evidence showing a battery involved in a fire on a 787 plane in Boston experienced “thermal runaway,” a so-called uncontrolled chemical reaction that occurs at high temperatures. The battery also short-circuited, she said.

The agency’s investigation into what caused the battery-related fire helped prompt the global grounding of Chicago-based Boeing’s new next-generation jets, “is not something that we’re expecting will be solved overnight,” NTSB Chairman Deborah Hersman said at a news conference. “There is a lot of technical work and a lot of complex work to understand” what happened and why. “We are prepared to do the methodical diligent work that needs to be done to really get to the root cause of this,” she said.

With the grounding of Boeing’s 787 plane in its ninth day, Hersman noted one battery test alone takes a week.

Hersman said the investigation is looking at certification of the 787 and has not ruled out whether the problem is isolated to the batteries or involves other systems.

“This aircraft has been in the air for less than 100 hours and to see two battery events within two weeks in the early flights of this aircraft is not what we would expect,” Hersman said.

The investigation followed a fire on a Japan Airlines 787 last week while it was empty of passengers and parked in Boston and an emergency landing of an All Nippon Airways 787 in Japan last week after its pilots smelled something burning and received a cockpit warning of battery problems. The Federal Aviation Administration and NTSB are helping Japanese authorities with the ANA investigation while the U.S. is leading the Boston investigation. Both incidents led to the grounding of the planes.

The 787 is 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 designed to prevent fires and contain a fire should one occur.

“We have a team that is looking at system certification standards,” Hersman said. “They are looking at what those certification standards adhered to and then the question of were they appropriate.

“...These events should not happen as far as design of the aircraft,” she said of the battery problems. “There are multiple systems to protect against a battery event like this. Those systems did not work as intended. We need to understand why.”

United Airlines was the only U.S. carrier flying the planes. It has six Dreamliners and is slated to receive two more in the second half of the year. The NTSB said it has asked United if it experienced any battery related events with the planes. Thursday, United reiterated its continued confidence in the 787 and said it expects to take delivery of two more in the second half of the year, including one in July.

The 787 is the world’s first airliner made mostly from lightweight composite materials. It also relies on electronic systems rather than hydraulic or mechanical systems to a greater degree than any other airliner.

Securaplane, an Arizona company that won a contract to design a battery charger unit for the Boeing 787, had a fire in November 2006 that ignited when the battery used by an engineering technician exploded during testing, destroying the firm’s labs and production building, according to a summary of findings prepared by an administrative law judge who heard a whistleblower complaint filed by the technician, who went to court after he was fired.

The technician, Michael Leon, said he complained to his employer that the battery was damaged and unsafe and that there were discrepancies between the schematics and assembly documents used in building the battery charger. Administrative Law Judge William Dorsey, who heard Leon’s complaint at trial, said in his ruling that one possible cause of the fire was Leon’s misuse of the battery during testing.

The FAA investigated Leon’s complaints in 2008 and 2009, the FAA said in a statement. “The investigation determined that the battery charging units in the complaints were prototypes, and none are installed in Boeing 787 aircraft,” the statement said. “Securaplane’s production of a particular printed circuit board complied with FAA requirements.”

Contributing: AP

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