But John Hansman, an aeronautics professor at MIT, said turning the MCAS system back on after disabling it would be a logical step for the pilots to take. If pilots find that the plane is repeatedly pointing the nose down, Boeing procedures say they should flip two switches to the left of their knees that would cut electrical power to motors that control a horizontal stabilizer on the tail. MCAS points the nose down by moving the stabilizer with the motors. After disabling the stabilizer, the pilots would have had to control it by turning a wheel manually to point the nose up.

Source: Los Angeles Times April 04, 2019 13:42 UTC