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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

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_Submittal_to_FAA_Oct_2019.pdf 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_Technical_Advisory_Board_Final_Report.pdf 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.

WalterBright 1y ago
Thank you for your detailed reply. A tendency to nose up is not "instability". Recall that additional pilot training to anticipate and correct for it was the original solution to the characteristic. A pilot unaware of it may react incorrectly. I have no disagreement with the shortcomings of the MCAS design, but the concept of it was sound. As for pilot skill, recall there were 3 MCAS incidents. The first one porpoised a couple times, with the pilots recovering each time, and then another crew member in the jump seat turned off the stab trim. In the second incident, the crew restored trim 25 times and never thought to turn off the trim system, over a period of 11 minutes. This is plenty of time to remember what the runaway trim cutoff switch is for. There's no excuse here. In the third incident, the crew apparently did not read, understand and remember the Boeing Emergency Airworthiness directive sent to all MAX pilots after the first crash, with a simple 2 step procedure to save the airplane. There's no excuse for that. I just find it baffling that a pilot would not be keenly interested in the only crash of the airplane type he is flying, to ensure he wouldn't crash. The stab trim switch is a memory item, meaning it is supposed to be memorized by the crew. It's their job to remember it. As for the two pilots I talked to, one contacted me as a result of these HN discussions. The other I buttonholed at the airport during layover. The latter was quite confident in his flying skills, the former related that he and his colleagues all agreed on the pilot error aspect. There are pilots in my family, I have friends who are pilots, I worked at Boeing where my colleagues were pilots. None of them had any patience for pilots who could not follow emergency procedures properly. I don't either. A careless pilot has no business in a cockpit.
- unsnap_biceps 1y ago
  > In the second incident, the crew restored trim 25 times and never thought to turn off the trim system, over a period of 11 minutes. This is plenty of time to remember what the runaway trim cutoff switch is for. There's no excuse here. > ... > The stab trim switch is a memory item, meaning it is supposed to be memorized by the crew. It's their job to remember it. The runaway trim memory item was written in a way that was inconsistent with how MCAS runaway behaved. The steps were: > Firmly hold control column. Disengage autopilot if engaged. Disengage autothrottle if engaged. Use the control column and thrust levers to control airplane pitch attitude and airspeed. Use main electric stabilizer trim to reduce control column forces. > If the runaway stops after autopilot is disengaged, do not re-engage autopilot or autothrottle; end of procedure. > If the runaway continues after autopilot is disengaged, place both STAB TRIM cutout switches to CUTOUT. > If the runaway continues, grasp and hold stabilizer trim wheel. Historic runaway stab was generally consistant running, not a cycle like MCAS, so following the check list, you turn off the auto pilot, trim stops, you consider you completed the checklist. When it fires off again, it's not completely unreasonable to believe that it's not a runaway trim, as you completed the checklist as instructed. As for the third incident, the Boeing Emergency Airworthiness directive specifically said that this issue only happened under manual control. The crew kept engaging the autopilot and when it continued to happen on the autopilot, it's not unreasonable for them to believe it wasn't the same issue per the Boeing Emergency Airworthiness directive. Could they have done better? sure. Could they have saved the aircraft if they followed a different train of thought? yes. Was their train of thought unreasonable? According to the investigation, no, it was not. To many many other people who study this stuff, no one that I'm aware of places any blame on the crew and it feels wrong to continue to shit on their skills when from all indications, they did follow procedures as written and it wasn't enough.

WalterBright 1y ago

Thank you for your detailed reply. A tendency to nose up is not "instability". Recall that additional pilot training to anticipate and correct for it was the original solution to the characteristic. A pilot unaware of it may react incorrectly. I have no disagreement with the shortcomings of the MCAS design, but the concept of it was sound. As for pilot skill, recall there were 3 MCAS incidents. The first one porpoised a couple times, with the pilots recovering each time, and then another crew member in the jump seat turned off the stab trim. In the second incident, the crew restored trim 25 times and never thought to turn off the trim system, over a period of 11 minutes. This is plenty of time to remember what the runaway trim cutoff switch is for. There's no excuse here. In the third incident, the crew apparently did not read, understand and remember the Boeing Emergency Airworthiness directive sent to all MAX pilots after the first crash, with a simple 2 step procedure to save the airplane. There's no excuse for that. I just find it baffling that a pilot would not be keenly interested in the only crash of the airplane type he is flying, to ensure he wouldn't crash. The stab trim switch is a memory item, meaning it is supposed to be memorized by the crew. It's their job to remember it. As for the two pilots I talked to, one contacted me as a result of these HN discussions. The other I buttonholed at the airport during layover. The latter was quite confident in his flying skills, the former related that he and his colleagues all agreed on the pilot error aspect. There are pilots in my family, I have friends who are pilots, I worked at Boeing where my colleagues were pilots. None of them had any patience for pilots who could not follow emergency procedures properly. I don't either. A careless pilot has no business in a cockpit.

unsnap_biceps 1y ago
> In the second incident, the crew restored trim 25 times and never thought to turn off the trim system, over a period of 11 minutes. This is plenty of time to remember what the runaway trim cutoff switch is for. There's no excuse here. > ... > The stab trim switch is a memory item, meaning it is supposed to be memorized by the crew. It's their job to remember it. The runaway trim memory item was written in a way that was inconsistent with how MCAS runaway behaved. The steps were: > Firmly hold control column. Disengage autopilot if engaged. Disengage autothrottle if engaged. Use the control column and thrust levers to control airplane pitch attitude and airspeed. Use main electric stabilizer trim to reduce control column forces. > If the runaway stops after autopilot is disengaged, do not re-engage autopilot or autothrottle; end of procedure. > If the runaway continues after autopilot is disengaged, place both STAB TRIM cutout switches to CUTOUT. > If the runaway continues, grasp and hold stabilizer trim wheel. Historic runaway stab was generally consistant running, not a cycle like MCAS, so following the check list, you turn off the auto pilot, trim stops, you consider you completed the checklist. When it fires off again, it's not completely unreasonable to believe that it's not a runaway trim, as you completed the checklist as instructed. As for the third incident, the Boeing Emergency Airworthiness directive specifically said that this issue only happened under manual control. The crew kept engaging the autopilot and when it continued to happen on the autopilot, it's not unreasonable for them to believe it wasn't the same issue per the Boeing Emergency Airworthiness directive. Could they have done better? sure. Could they have saved the aircraft if they followed a different train of thought? yes. Was their train of thought unreasonable? According to the investigation, no, it was not. To many many other people who study this stuff, no one that I'm aware of places any blame on the crew and it feels wrong to continue to shit on their skills when from all indications, they did follow procedures as written and it wasn't enough.