Crew members of the Ethiopian Airlines jetliner that crashed shortly after takeoff last month followed procedures prescribed by the aircraft's manufacturer, according to a report released Thursday.
The preliminary report, released by the Ethiopian government, concluded the crew was unable to regain control of the American-made Boeing 737 Max 8, despite following recommended procedures.
The report is based on information from the recorders of the aircraft. It reinforces uncertainty about the reliability of the system that controls the Boeing jetliner, which has been grounded worldwide for nearly a month.
The plane was grounded after the Ethiopian Airlines flight crashed into a field outside Addis Ababa just minutes after takeoff on March 10, killing all 157 people on board. The Max 8 had been under scrutiny since October, when 189 people were killed when a Lion Air flight crashed off the coast of Indonesia under similar circumstances.
The focus of the investigation is the plane's flight-control system, which can automatically lower the plane's nose to avert an aerodynamic stall. Boeing is working on a software fix, which needs approval from the U.S. Federal Aviation Administration (FAA) and other regulators.
Boeing, which has declined to comment until it has reviewed the report, is also being investigated by the U.S. Justice Department, the U.S. Transportation Department and U.S. congressional committees. Investigators are scrutinizing the role of the FAA, which approved the plane for service in 2017 and refused to ground it after the first crash in October.
The FAA was subjected to tough questioning about its oversight of Boeing at a congressional hearing last week. The FAA said it expected Boeing to submit the proposed software fix "over the coming weeks."