The path has been cleared for Boeing 787 Dreamliners to resume service within weeks.
The US Federal Aviation Administration approved a set of fixes to the 787 batteries put forward by Boeing, which requires it to “conduct extensive testing and analysis”.
The regulator also gave the green light to limited test flights for two aircraft to test upgrades to the lithium ion batteries.
The Financial Times reported a person familiar with the situation saying that the company was seeking a return to commercial flights within three to four weeks.
All 50 Dreamliners in operation have been grounded and orders delayed following a fire in a battery on a Japan Airlines 787 in Boston on January 7 and an emergency landing by an All Nippon Airways aircraft in Japan shortly afterwards when a battery started producing smoke.
US transportation secretary Ray LaHood said: “This comprehensive series of tests will show us whether the proposed battery improvements will work as designed.”
But he added: “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.”
Boeing chief executive Jim McNerney said the approval from the FAA is a “critical and welcome milestone towards getting the fleet flying again and continuing to deliver on the promise of the 787”.
The FAA confirmed: “The certification plan is the first step in the process to evaluate the 787’s return to flight and requires Boeing to conduct extensive testing and analysis to demonstrate compliance with the applicable safety regulations and special conditions.”