Ethiopian Airlines flight ET302 crashed shortly after takeoff from Addis Ababa on March 10th 2019, it was operated with a Boeing B737 Max 8.
Ethiopian Airlines flight ET302 was bound to Nairobi, Kenya Jomo Kenyatta Int. Airport. Shortly after takeoff, the Angle of Attack sensor recorded value became erroneous and the left stick shaker activated and remained active until near the end of the flight.
In addition, the airspeed and altitude values from the left air data system began deviating from the corresponding right side values.
Due to flight control problems, the Captain of Ethiopian Airlines flight ET302 was unable to maintain the flight path and requested to return back to the departure airport.
The crew lost control of the aircraft which crashed at 5: 44 UTC 28 NM South East of Addis Ababa near Ejere village.
INITIAL FINDINGS : On the basis of the initial information gathered during the course of the investigation, the following facts have been determined:
- The Aircraft possessed a valid certificate of airworthiness;
- The crew obtained the license and qualifications to conduct the flight;
- The takeoff roll appeared normal, including normal values of left and right angle-of-attack (AOA).
Shortly after liftoff, the value of the left angle of attack sensor deviated from the right one and reached 74.5 degrees while the right angle of attack sensor value was 15.3 degrees;
- the stick shaker activated and remained active until near the end of the flight.
- After autopilot engagement, there were small amplitude roll oscillations accompanied by lateral acceleration, rudder oscillations and slight heading changes; these oscillations also continued after the autopilot disengaged.
- After the autopilot disengaged, the DFDR recorded an automatic aircraft nose down (AND) trim command four times without pilot’s input. As a result, three motions of the stabilizer trim were recorded. The FDR data also indicated that the crew utilized the electric manual
trim to counter the automatic AND input.
- The crew performed runaway stabilizer checklist and put the STAB TRIM CUTOUT switch to cutout position and confirmed that the manual trim operation was not working.