Boeing Co.'s 787 Dreamliner won U.S. regulators' approval to return to service with a redesigned lithium-ion battery, more than three months into the government's longest grounding of a commercial model in the jet age.
Airlines will get instructions next week on how to modify their planes, along with the final directive allowing 787s to fly, the Federal Aviation Administration said Friday.
The Dreamliner's eight current operators will be able to restart flights as batteries are replaced and pilots recertified. Chicago-based Boeing also will be able to resume deliveries.
Neither the FAA nor the National Transportation Safety Board has determined what caused the battery faults that sparked a Jan. 7 fire on a Japan Airlines 787 in Boston and forced an emergency landing by an ANA jet in Japan nine days later.
The revised battery includes more protection around cells to contain overheating, a steel case to prevent any fire from spreading and a tube that vents fumes outside the fuselage.
"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," FAA Administrator Michael Huerta said in a statement.