The theory suspected by U.S. aviation officials is that a bird strike caused erroneous input to set off the plane’s autopilot system, Maneuvering Characteristics Augmentation System (MCAS), a source familiar with the situation told CNBC.
Boeing last month revealed that faulty sensors on the aircraft were behind the fatal crash in March that reportedly killed everyone on board.
An initial report determined the aircraft had a faulty “angle of attack” sensor, which tracks lift to prevent stalling, Boeing said in a statement at the time. The plane’s pilots were unsuccessful in their attempts to readjust the angle.
But results from an early investigation into the incident uncovered “no evidence of any foreign object damage” on the sensor, Ethiopian Airlines has said, according to CNBC.
Fox Business’ Joe Williams and Ken Martin contributed to this report.