One week after Federal Aviation Administration officials grounded Boeing's newest jet, the world's entire 787 Dreamliner fleet remains parked. FAA Administrator Michael Huerta said Tuesday he couldn't speculate on when a review of the plane would be complete.

Investigators in the U.S. and Japan remain perplexed as to why batteries on two planes suffered serious failures. Now Boeing, its flagship jet and the certification process for the 787 are under intense scrutiny.

Everyone working on the 787 knew that lithium-ion batteries, which pack an enormous amount of power into a small package, require special care. While the batteries have a history of fires, Boeing and government regulators thought they had the battery issues under control.

But earlier this month, a battery on a brand-new Japan Air Lines 787 caught fire. Less than 48 hours later, a battery on an All Nippon Airways 787 overheated and sustained major damage, forcing the pilot to make an emergency landing.

An Outsourced Plane

John Goglia, a former member of the National Transportation Safety Board, says investigators must look at several things as they try to assess the source of the plane's problems.

First, he says, is determining if there is a design or manufacturing defect in the batteries themselves. In the case of the two problem batteries, it appears they may have come from the same production batch.

Goglia says investigators are looking at other parts of the electrical system as well.

"They're looking at the battery charger, the circuitry and the protections the charging system has, and they're looking at the electronics system in general of the airplane," he says, "because it could be possible that additional current was coming in from another source on the airplane."

Boeing outsourced the design, engineering and production of the Dreamliner to an unprecedented degree — 65 percent of the plane is not made by Boeing. The batteries were made by a Japanese company, as part of the electrical system supplied by a French firm.

"It's always a difficult challenge to ensure that subcontractors are implementing the same high standards for quality assurance and quality control in their individual components," says attorney Kenneth Quinn, former chief counsel for the FAA.

Relying On Manufacturers For Testing

There's another quality issue under new scrutiny: the FAA's certification process itself. While there is no evidence that the recent 787 incidents can be linked to insufficient oversight, the problems have left some asking precisely how the approval process works.

The FAA is responsible for certifying new planes, but the agency is chronically understaffed and, to some extent, lacking expertise in some of the latest technologies. That leaves the agency heavily reliant on manufacturers like Boeing.

"The thing that people don't understand is the FAA does not generate any of the data for any airplane that's certificated," explains John McGraw, a former deputy director of flight standards at the FAA. "It's all generated by the manufacturer."

McGraw, now an aviation consultant, says that certain Boeing employees are allowed to sign off on some performance tests on behalf of the FAA.

While the idea of delegating certain tests to manufacturers has been around for decades, the companies have been given more authority since 2005. But much of that delegated responsibility, McGraw says, is relatively routine work.

"The more cutting-edge, latest technology, systems and items are reserved for the FAA to actually get involved with," he says.

The Dreamliner's battery falls into that category. Overall, the FAA says its technical experts logged some 200,000 hours testing and reviewing the plane's design.

The FAA is now conducting a high-level review of the 787's electrical system — and its own role in certifying the new jet.

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