by throwaway5752 | 2025-06-06 04:33:09+00:00
I appreciate the civil and informed discussion. I appreciate your expertise and connections, but I think we will end up disagreeing.

I think interested parties should look at the JATR report (Joint Authorities Technical Review Observations, Findings, and Recommendations) -https://www.faa.gov/sites/faa.gov/files/2021-08/Final_JATR_S...

With respect to "unstable", I will quote the findings

"Observation O3.4-B: Extension of MCAS to the low-speed and 1g environment during the flight program was due to unacceptable stall characteristics with STS only. The possibility of a pitch-up tendency during approach to stall was identified for the flaps-up configuration prior to the implementation of MCAS"

Regarding flight crew expectations, this is dry, but I will quote it in its entirety, anyway,

"Recommendation R6.1: The FAA should ensure applicants improve adherence to failsafe design concept principles when designing or modifying systems. The FAA should encourage applicants not to design only for compliance, but also to follow basic principles to design for safety when developing or changing system functions. This should include elimination of hazards and use of design features, warnings, and procedures.

- Observation O6.1-A: Proper flight crew action was considered an adequate mitigation to risks such as erroneous activation of MCAS.

- Finding F6.1-A: The JATR team identified that the design process was not sufficient to identify all the potential MCAS hazards. As part of the single-channel speed trim system, the MCAS function did not include fault tolerant features, such as sensors voting or limits of authority, to limit failure effects consistent with the hazard classification.

- Finding F6.1-B: The use of pilot action as a primary mitigation means for MCAS hazards, before considering eliminating such hazards or providing design features or warnings to mitigate them, is not in accordance with Boeing’s process instructions for safe design in the conception of MCAS for the B737 MAX.

- Finding F6.1-C: The JATR team found that there was a missed opportunity to further improve the system design through the use of available fail-safe design principles and techniques presented in AC 25.1309-1A and in EASA AMC 25.1309 in the MCAS design"

and further, on flight crew expectations

"Finding F6.4-A: When all flight deck effects are considered, the introduction of the MCAS function invalidated aircraft-level assumptions for flight crew responses related to erroneous AOA failures under certain conditions. A complete workload assessment was not performed for validation of the erroneous AOA effects with the added MCAS functionality. The same assumptions for flight crew responses to erroneous AOA were carried over from previous programs without formal validation."

The Technical Advisory Board's report is also interesting - https://www.faa.gov/sites/faa.gov/files/2022-08/737_Technica...

The discussion around AOA DISAGREE conditions is educational regarding MCAS for others who might not be familar with the technical root cause. But I would specifically encourage you to read the Flight Controls and Flight Deck Interface Assessment and Training Evaluations. They don't avoid the issue of flight crew training and trim system awareness, but I they illustrate how workload created by the erroneous MCAS activation was contributing.

As for your pilot conversations, I will make two short points. First, pilots don't always suffer for a lack of self-confidence. Maybe it would have never happened to them, maybe not, and thankfully we will not get to find out. Second, passengers are owed a safe aircraft based on the full range of quality flight crews, with a wide margin for error. I do care if a highly skilled qualified crew would have avoided the accident, I care if the least-skilled qualified crew would have. And 610's captain had 5,176 hours on the 737 and 302's captain had 4,120 hours.