Boeing will start conducting certification test flights starting Monday on its controversial 373 Max aircraft, which has been grounded across the world since March 2019. Reuters reports that the three-day test flights near Seattle are the first step in getting the aircraft back in the sky after crashes killed 346 people in Ethiopia and Indonesia. The crew will run mid-air scenarios such as the steep-banking turns and other maneuvers similar to those that led to the fatal crashes. The planes will endeavor touch-and-go landings, mid-air flight plan changes and deliberately triggering the MCAS anti-stall system that is tied to the fatal crashes. After the test flights, the FAA will analyze data to assess whether the jet is airworthy. If the 737 Max passes the tests, the FAA would then approve new pilot training. The ungrounding of the once-popular aircraft is not expected before September 2020.