Satellite transponders on aircraft record the position, altitude, direction, and speed every eight seconds. The Boeing officials showed Bahrami and his team a graphic that superimposed these traces from the flight in Ethiopia over the Lion Air plane’s last moments. It was a match. In addition, a piece of the plane had been recovered that showed the flaps were in an “up” position—a precondition for MCAS to fire. There was nothing more to say; Bahrami walked out of his office and told his boss they needed to ground the fleet.
