The Accident Investigation Bureau today issued a preliminary report on the accident of the Boeing 737 MAX 8 operating flight ET302 on 10 March 2019. Here is its Executive Summary:
On March 10, 2019, at 05:38 UTC, Ethiopian Airlines flight 302, Boeing 737-8(MAX), ET-AVJ, took off from Addis Ababa Bole Int. Airport 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 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 05:44 UTC 28 NM South East of Addis Ababa near Ejere village.
Boeing issued the following statement regarding the release today of the preliminary investigation report of Ethiopian Airlines Flight ET302 by the Ethiopian Accident Investigation Bureau (AIB). The Ethiopian Airlines statement has been published here earlier. The full preliminary report is available here (pdf).
“I’d like to reiterate our deepest sympathies are with the families and loved ones of those who lost their lives in the accident,” said Boeing Commercial Airplanes President and CEO Kevin McAllister. “We thank Ethiopia’s Accident Investigation Bureau for its hard work and continuing efforts. Understanding the circumstances that contributed to this accident is critical to ensuring a safe flight. We will carefully review the AIB’s preliminary report, and will take any and all additional steps necessary to enhance the safety of our aircraft.”
Safety is a core value for everyone at Boeing and the safety of its aeroplanes, its customers’ passengers and crews is always a top priority. Boeing’s technical experts continue to assist in this investigation and company-wide teams are working to address lessons from the Lion Air Flight 610 accident in October.
The preliminary report contains flight data recorder information indicating the aeroplane had an erroneous angle of attack sensor input that activated the Maneuvering Characteristics Augmentation System (MCAS) function during the flight, as it had during the Lion Air 610 flight.
To ensure unintended MCAS activation will not occur again, Boeing has developed and is planning to release a software update to MCAS and an associated comprehensive pilot training and supplementary education program for the 737 MAX.
As previously announced, the update adds additional layers of protection and will prevent erroneous data from causing MCAS activation. Flight crews will always have the ability to override MCAS and manually control the aeroplane.
Boeing continues to work with the U.S. Federal Aviation Administration and other regulatory agencies worldwide on the development and certification of the software update and training program.
Boeing also is continuing to work closely with the U.S. National Transportation Safety Board (NTSB) as technical advisors in support of the AIB investigation. As a party providing technical assistance under the direction of investigating authorities, Boeing is prevented by international protocol and NTSB regulations from disclosing any information relating to the investigation. In accordance with the international protocol, information about the investigation is provided only by investigating authorities in charge.