The US Federal Aviation Administrator (FAA) Steve Dickson has cleared the way for the Boeing 737 Max plane to fly again after two years on the ground in the wake of two deadly accidents, the FAA said in a statement.

“FAA Administrator Steve Dickson today signed an order [PDF] that paves the way for the Boeing 737 MAX to return to commercial service. Administrator Dickson’s action followed a full safety review process [PDF] and methodical that took 20 months to complete”

After two fatal accidents involving the 737 MAX, a Lion Air accident in Indonesia in October 2018 and the Ethiopian Airlines accident in March 2019, the FAA and other regulators around the world grounded the aircraft and manufacturer Boeing suspended production of the aircraft.

Accident investigations revealed errors in the operation of the aircraft’s piloting system, failures in Boeing’s standard safety procedures, and cover-ups by company officials.

“In addition to rescinding the order that grounded the aircraft, the FAA today issued an Airworthiness Directive specifying the design changes that must be made before the aircraft returns to service, issued a Continued Airworthiness Notification to the International Community ( CANIC) and published the MAX training requirements,” according to the FAA statement adding that “these actions do not allow the MAX to immediately return to the skies.”

The FAA must approve 737 MAX pilot training program reviews for each the U.S. airline operating the MAX and will retain its authority to issue airworthability certificates and airworthability export certificates for all new 737 MAX aircraft manufactured since the FAA issued the grounding order.

Airlines that have parked their MAX jets must also take the necessary maintenance steps to prepare them to fly again, the FAA said.