A top US air safety regulator said Wednesday he was pleased with a 737 MAX test flight he piloted, but that more work was needed to recertify the jet.

"I like what I saw on the flight," said Federal Aviation Administrator Steve Dickson, who called the flight part of the agency's due diligence.

Dickson has "some observations I'm going to share," he said. "That will be incorporated into the process going forward."

The test flight marked the latest landmark in the MAX's torturous path to returning to work after it was grounded in March 2019 following two crashes that killed 346 people.

The crashes have badly dented Boeing's reputation and that of the FAA, which had long been considered the "gold standard" among international bodies.

A Boeing 737 MAX airliner piloted by Federal Aviation Administration (FAA) Administrator Steve Dickson lands following an evaluation flight in Seattle, Washington
A Boeing 737 MAX airliner piloted by Federal Aviation Administration (FAA) Administrator Steve Dickson lands following an evaluation flight in Seattle, Washington AFP / Jason Redmond

A withering congressional report released earlier this month slammed both Boeing and the FAA, pointing in particular to failures to sufficiently vet the Maneuvering Characteristics Augmentation System (MCAS), an anti-stall system that has been seen as a central factor in both crashes.

Dickson participated in a simulator training session on the MAX prior to undertaking a two-hour test flight of the plane that included two landings and checks on the MCAS.

The MAX "responded well," Dickson said. "The training prepared me to be very comfortable."

Next steps in the process include reviewing public comments on a proposed airworthiness directive and finalizing the pilot training regime.

The FAA flight comes after European Union air safety chief Patrick Ky said last week that the MAX could receive certification to fly again in Europe "by the end of the year."