The Federal Aviation Administration announced Friday that it has formally approved Boeing's design for modifications to the 787 Dreamliner battery system, clearing the way to end the plane's three-month grounding.
Boeing Co. said it will immediately begin modifying the 50 already-delivered 787s around the world and that regular deliveries will resume soon.
FAA spokeswoman Laura Brown said the agency hasn't changed the Dreamliner's ETOPS, or extended operations, certification, which means the 787 keeps its regulatory approval to fly up to three hours away from the nearest airport.
In a statement, Boeing CEO Jim McNerney said the decision "clears the way for us and the airlines to begin the process of returning the 787 to flight with continued confidence in (its) safety and reliability."
Despite the unprecedented setback of the grounding, McNerney said "the promise of the 787 and the benefits it provides to airlines and their passengers remain fully intact."
Government officials insisted that Boeing's new battery design ensures the safety of the airplane. Transportation Secretary Ray LaHood said the safety of the traveling public remains "our No. 1 priority." And FAA chief Michael Huerta said he reached the decision to approve the fix only after "a team of FAA certification specialists observed rigorous tests we required Boeing to perform and devoted weeks to reviewing detailed analysis of the design changes."
Boeing engineers "spent more than 100,000 hours developing test plans, building test rigs, conducting tests and analyzing the results to ensure the proposed solutions met all requirements," the jetmaker said in a statement.
The redesigned battery "made a great airplane even better," said Boeing Commercial Airplanes CEO Ray Conner.
The FAA will issue instructions to airlines next week detailing the Boeing-designed modifications and will publish in the Federal Register the final directive that will allow the modified 787s to return to passenger service.
The modifications include a steel containment box and a titanium tube connecting the box and the fuselage skin that will suck any gases, including oxygen, out of the box and prevent a fire. Boeing also has added electrical and thermal insulation around the eight cells of the battery to minimize short circuits and prevent any overheating within one cell from spreading to the others.
The FAA said it will have teams of inspectors ready at locations where the 787s are being modified. Any return to service of the modified 787 will take place only after the FAA accepts the work.
As the certifying authority, the FAA also will work with other regulatory authorities around the world as they finalize their own acceptance procedures.