After nearly a month of waiting for approval, the Federal Aviation Administration, on Tuesday, upon a comprehensive review of Boeing's plan, has given the aircraft maker FAA authorization to go ahead with their certification plan for the 787 Dreamliner's lithium-ion battery system and start air testing.

Boeing's plans call for redesigning the eight-cell batteries to minimize the risk of a short-circuit, which caused a fire in a Dreamliner parked in Boston on Jan. 7.

Though, the FAA gave their blessing, the catch is that Boeing can only do limited test flights for only two aircraft, which will have redesigned batteries and enclosures. Testing will cover each plane's two batteries and other systems.

"This comprehensive series of tests will show us whether the proposed battery improvements will work as designed," Transportation Secretary Ray LaHood said. "We won't allow the plane to return to service unless we're satisfied that the new design ensures the safety of the aircraft and its passengers," according to USA Today.

Boeing will also better insulate each battery's eight cells, will add a new fireproof shell to surround the battery and install a venting system for smoke if there is a fire. 

"We are confident the plan we approved today includes all the right elements to conduct a comprehensive evaluation of the battery system redesign," FAA Administrator Michael Huerta said. "Today's announcement starts a testing process which will demonstrate whether the proposed fix will work as designed," reported USA Today.

Boeing CEO Jim McNerney called FAA's approval a critical and welcome milestone toward getting the fleet flying again.

"Our top priority is the integrity of our products and the safety of the passengers and crews who fly on them," McNerney said, according to USA Today.

The issues of the Lithium-ion batteries, which caused two fires, one, in an Air Nippon Airways' Dreamliner, at Boston's Logan Airport, caused the FAA to ground all Dreamliners, which, in turned, cost Boeing and the airlines with Dreamliners in their fleet to lose massive amounts of money, both in sales and customer revenue.

In an effort to recoup some of that lost revenue, Air Nippon Airways, even though no action has been taken yet, has threatened Boeing with a lawsuit.

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