The assumption of a loss of control of the Boeing 737 MAX has not been sufficiently taken into account in the design and certification of the MCAS anti-stall system of the aircraft, say the Indonesian authorities in their final report on the Lion Air accident in October 2018.
The disaster of October 29, 2018, which killed 189 people, was followed less than five months later by another accident involving a 737 MAX in Ethiopia (157 dead), which led to the immobilization of this type of device last March.
In the final report on the Lion Air accident, the Indonesian National Committee for Safety in Transport (KNKT) makes several recommendations to Boeing, the Indonesian airline and the US Civil Aviation Authority ( FAA).
A copy of the report was available to Reuters before it was published during the day.
“In the design and certification of the MCAS, the possibility of a loss of control of the device was not adequately considered,” reads the document.
The agency also points out that the lack of information on MCAS in textbooks has made it difficult for pilots to diagnose problems.
In a statement, the aircraft manufacturer said he took good note of the KNKT recommendations. Boeing has made changes to its anti-stall system in recent months, but these have not yet been validated by the FAA. The Seattle group hopes the 737 MAX will come back online before the end of the year in the United States.
According to the KNKT, an angle of attack sensor providing data to the MCAS system has been misaligned by a company in Florida and the agency strongly suspects that it has not been tested when it was installed on aircraft. Lion Air.
The Indonesian company should also have immobilized its 737 MAX following problems observed in previous flights.
The report also points to communication failures within the crew and flaws in the manual control of the aircraft.
Finally, he believes that the FAA has delegated much of its authority to Boeing during the MCAS certification process.
The role of the FAA has already been called into question by the Joint Authorities Technical Review (JATR), a committee of experts from nine countries, in a report published on October 11.