The Boeing 737 MAX

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On 30 August 2011 Boeing launched the 737 MAX as a derivative of the existing 737. Certification as a change to the existing type, and pilot transition by differences training without simulator time, both rested on that founding decision. In March 2016 a redesign increased the authority of the flight-control software MCAS at low speed. Lion Air Flight 610 crashed on 29 October 2018 and Ethiopian Airlines Flight 302 on 10 March 2019. Together the 2 crashes killed 346 people.

What the investigations documented. The Joint Authorities Technical Review found that the changed-product certification process was followed and worked for discrete changes, but did not adequately address cumulative effects or how changes interacted across the whole aircraft. The US House Committee on Transportation and Infrastructure found that the FAA officials who approved removing references to MCAS from the flight crew manual did not learn of the redesign until after the first crash. The investigations set out many findings across design, certification, training, maintenance and oversight. This page does not reduce the findings to a single cause.

The Kettei reading. Separately from those findings, the article reads the reports with the decision as the unit of analysis, rather than the outcome. Rules and review mechanisms existed. What the record does not show is a person accountable for the founding derivative assumption, with a written trigger on it and a declared link to the MCAS design and the training commitment. That is an interpretation, offered as a question for any organisation, and it is not a finding of the inquiries. It does not claim that Kettei would have prevented the accidents. A trigger creates an obligation to review; whether a review is honest and acted on depends on the people in the room.