Dreamliner battery charger eyed in jet probe

• Investigation could take days%2C weeks
• Planes are grounded until battery problems are resolved
• Experts are confident the problems will be found%2C fixed

WASHINGTON — Federal investigators plan to test the battery charger and other electronics from Boeing's 787 Dreamliner on Tuesday in an effort to track down what went wrong with the batteries in the grounded aircraft.

Investigators from the National Transportation Safety Board (NTSB) plan the tests at the Tucson headquarters of the charger's manufacturer, Securaplane Technologies. Investigators also have wire bundles and battery-management circuit boards to test from a plane that caught fire Jan. 7 in Boston.

"They need to make sure they account for all of these unforeseen things that can happen," says Prashant Kumta, a battery expert and engineering professor at the University of Pittsburgh.

Oliver McGee, an aerospace engineer who is a former deputy assistant secretary of Transportation, says technology in the plane includes millions of miles of wires and millions of lines of computer code, and involves numerous contractors.

"You have to put the puzzle back together again," says McGee, who urges patience on the investigation.

The testing comes nearly a week after regulators grounded 50 Dreamliners worldwide Jan. 16. The groundings followed the Boston fire aboard a Japanese Airlines plane and an emergency landing Jan. 16 in Japan of an All Nippon Airways flight because of a smoldering battery.

In another vein, investigators from the Federal Aviation Administration and from Japan's Civil Aviation Bureau visited the battery manufacturer, GS Yuasa in Japan, on Monday.

Tatsuyuki Shimazu, the chief air worthiness engineer at the Japanese bureau's Aviation Safety Department, says they are collecting information about how the batteries are made, so "whether there is a problem or not has not yet been determined."

Boeing, which has nearly 850 Dreamliners on order and is cooperating with the investigation, has halted deliveries until the electrical problems are resolved.

Airlines have already canceled hundreds of flights through Jan. 29, suggesting they expect the problem to take at least that long to fix.

Richard Aboulafia, vice president for analysis at the Teal Group, a consultant for commercial and military aircraft companies, says if the problem lasts more than a couple of weeks, it will create questions about how airlines can serve their routes. But he says Boeing is doing what it can to find and fix the problem.

"It's a big concern," Aboulafia says. "You don't want your new flagship aircraft taken offline."

Lithium-ion batteries are popular because they are smaller and charge faster than other batteries. But Kumta, the battery expert, says the concern is that the batteries, which are filled with a flammable liquid called an electrolyte, can explode or cause a fire when overheated or ruptured.

The Boston battery could have had charging problems even though NTSB found that it never received more than the 32 volts it was designed for, Kumta says. That's because the charger is supposed to let the battery run down before recharging, just like a cellphone or laptop is supposed to run down before plugging it back in. If the charger didn't match the battery's needs precisely, Kumta says, it could cause problems.

In addition, battery experts have questioned whether enough testing was done on batteries to mimic the temperature and pressure of flight. The battery would essentially seek to burst open in flight if not pressurized or built for different pressure at altitude, according to battery experts.

"With all of these, there might be a slight miscalculation or misjudgment," Kumta says.

He is confident, however, that any problem with the battery could be fixed.

"You learn from experience," Kumta says. "It's a new application, and people have to learn from it."

Contributing: The Associated Press