U.S. Federal Aviation Administrator Steve Dickson said on Thursday international air safety regulators were likely to agree on the design fixes needed to return the Boeing 737 Max aircraft to service.

Dickson, the U.S. regulator who has responsibility for approving a return to service by the grounded 737 Max, said he wouldn't put a timeframe on its return but that it would become easier to predict after its certification flight, which he said could come in the next few weeks.

The 737 Max was grounded in March 2019 after two fatal crashes that killed 346 people.