Boeing began on Monday a test flight to determine whether the revamped 737 MAX is safe after fatal crashes grounded the jet worldwide last year.

The flight took off from an airfield near Seattle and flew through eastern Washington state before dipping down into Oregon and eventually returning back to the Seattle area.

Flight enthusiasts around the world followed in real time as the aircraft flew over central Washington and performed maneuvers such as stalls, based on airspeed and altitude data on FlightRadar24.

The Federal Aviation Authority (FAA) has approved the certification test flights after Boeing submitted safety fixes to the FAA for review.

The flight is a milestone toward ending a grounding imposed worldwide in March last year after the two crashes of Boeing's best-selling model killed 346 people.

(CGTN)