The European Union Aviation Safety Agency (EASA) said on Thursday it plans to begin flight tests of U.S. planemaker Boeing Co.’s 737 MAX plane in Vancouver, Canada, in the week starting Sept. 7.The test flights will start more than two months after the U.S. regulator, the Federal Aviation Administration (FAA), and Boeing completed certification test flights on the 737 MAX, a move viewed as a key milestone toward its return to service.

The jets have been grounded since March 2019 after two fatal crashes in five months killed 346 people.

“While Boeing still has some final actions to close off, EASA judges the overall maturity of the re-design process is now sufficient to proceed to flight tests,” the agency said.

EASA has been working with the FAA and Boeing to schedule the flight tests, a process which was hindered by COVID-19 travel restrictions between Europe and the United States.

Meanwhile, pilots from Boeing and Canada’s transportation watchdog Transport Canada started flight tests of the 737 MAX jetliner on Wednesday, according to one industry source and FlightAware data.

Once the countries complete their flights tests, the Joint Operational Evaluation Board, which includes regulators from Canada, Europe and Brazil, will run simulator exercises to evaluate proposed changes to pilot training.

If reviews of the 737 MAX’s safety upgrades and accompanying training protocols do not raise new concerns, the FAA will issue an order rescinding the grounding of the plane.

Boeing told analysts in late July that 737 MAX deliveries would resume in the fourth quarter, a timeline that raises the prospect that the aircraft’s U.S. return to service could slip into 2021.

The U.S. jet manufacturer’s shares were up 0.6% at $172.90 in premarket trading.

(Reporting by Ankit Ajmera in Bengaluru; Editing by Sriraj Kalluvila and Arun Koyyur)

Photo: A Boeing 737 MAX airplane sits with dozens of others crowding a parking area adjacent to Boeing Field Thursday, Aug. 15, 2019, in Seattle. (AP Photo/Elaine Thompson)