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I think it's not just that question and this is what I dislike about the whole discussion. It's all about Boeing and no one is also asking "if proper procedure

I think it's not just that question and this is what I dislike about the whole discussion. It's all about Boeing and no one is also asking "if proper procedure was performed for runaway stab trim (again, a generalized memory item) would the plane have crashed? And it does seem the sentiment is to hell with anyone suggesting pilots and airlines involved share part of the blame despite evidence. I could also ask, would the plane have crashed if it WASNT a max and another stab trim system failed? It's both. We need to look at everything otherwise we will end up solving only 1 part of the issue. Edit: To address something you mentioned about root cause (in aviation it's almost never a single root cause and I will give an example that shows such cases here). Let's look at another situation: Assume P&W designs an engine model a plane uses. The plane they are used in has in-air engine fire procedures that must be performed in order to mitigate disaster regardless of the engine model used. Now imagine the new engine design causes more engine fires. If pilots don't manage the problem appropriately when it occurs, what is the root cause? The poor engine design? Improper training from the pilot? In my opinion it's, again, both. Poor training coupled with higher chance of system issues.

im_down_w_otp 7y ago
The pilots and the airlines didn't design, build, and release a semi-autonomous system which isn't resilient to erroneous data, despite the failure case for that problem being catastrophic. If an Automotive OEM released a vehicle with an adaptive cruise control system that refused to disable itself except by the human driver intervening through power cycling the vehicle, while driving, it's difficult to put much warranted blame on the driver. The OEM sold a potentially catastrophically faulty system, irrespective of that the fault can sometimes be managed into a fail-safe condition by the driver. The reason people put the blame on Boeing is because the system implementation didn't fail, the design did.
- CorvusCrypto 7y ago
  It doesn't refuse to disable. People are mixing this up with overriding control inputs. It is still possible to take MCAS out if the control loop using stab trim cutout. However when left active it does override pilot inputs. Think of it as the alpha authority that exists on airbuses. However if you follow proper stab trim runaway procedures you cutout stab trim taking MCAS out which restores pilot authority. Again this procedure should be second nature to 737 pilots of any submodel. In your example, if there were adaptive cruise control, I would turn off cruise control by hitting the button. Same options are present here. However it does mean that braking or acceleration would be overriden until that happens. But the real analogy is if all drivers had to be trained that you turn off cruise control in runaway. If you don't do that, well then you will crash and it's from system failure AND improper general procedure
  - im_down_w_otp 7y ago
    The example analog I chose is actually a thing, and hitting the button does nothing. The problem is in the design. Despite the fact that it's possible to defeat the failure in some instances (assuming it hopefully doesn't manifest itself too close to the disaster envelope to start with), the failure case 1) never should have happened and 2) shouldn't require unintuitive remediation. It's bad design and bad functional-safety analysis. Neither of which fall to the fleet operator or system operator.
    - CorvusCrypto 7y ago
      Yes I agree. And I'm pleading that everyone also recognise the other aspects of these.incidents such as improper basic procedure. It's all of the above. Edit: And remember at the end of the day, these airlines and pilots agreed to fly the plane. Even in the wake of the LionAir incident. At the end of the day, the pilots choose to fly and can say no if they aren't comfortable. And if the answer to this is that there is pressure from airlines to keep flying? We just found another major issue and danger in aviation Edit2: should clarify actually that I agree it's a bad design. Not about the procedures being "unintuitive". If the pilots think the corrective procedures are unintuitive they shouldn't fly any 737 since stab trim systems exist on all 737s and require the same corrective procedure in runaway stab trim.
      - cmurf 7y ago
        Are you a pilot? If so what are your qualifications? Have you read the ET302 preliminary report? In particular have you read page 25, section 2 "Initial findings" last bullet which I quote: The crew performed runaway stabilizer checklist and put the stab trim cutout switch to cutout position and confirmed that the manual trim operation was not working. How can you read that, and say multiple times in this thread "improper procedure"? On what basis? You have no idea how much mental discipline it's taking me, as a pilot, to refrain from ad hominem attack. Your arguments are that bad, they are that willfully contrary to the available facts.
        7y ago

im_down_w_otp 7y ago

The pilots and the airlines didn't design, build, and release a semi-autonomous system which isn't resilient to erroneous data, despite the failure case for that problem being catastrophic. If an Automotive OEM released a vehicle with an adaptive cruise control system that refused to disable itself except by the human driver intervening through power cycling the vehicle, while driving, it's difficult to put much warranted blame on the driver. The OEM sold a potentially catastrophically faulty system, irrespective of that the fault can sometimes be managed into a fail-safe condition by the driver. The reason people put the blame on Boeing is because the system implementation didn't fail, the design did.

CorvusCrypto 7y ago
It doesn't refuse to disable. People are mixing this up with overriding control inputs. It is still possible to take MCAS out if the control loop using stab trim cutout. However when left active it does override pilot inputs. Think of it as the alpha authority that exists on airbuses. However if you follow proper stab trim runaway procedures you cutout stab trim taking MCAS out which restores pilot authority. Again this procedure should be second nature to 737 pilots of any submodel. In your example, if there were adaptive cruise control, I would turn off cruise control by hitting the button. Same options are present here. However it does mean that braking or acceleration would be overriden until that happens. But the real analogy is if all drivers had to be trained that you turn off cruise control in runaway. If you don't do that, well then you will crash and it's from system failure AND improper general procedure
- im_down_w_otp 7y ago
  The example analog I chose is actually a thing, and hitting the button does nothing. The problem is in the design. Despite the fact that it's possible to defeat the failure in some instances (assuming it hopefully doesn't manifest itself too close to the disaster envelope to start with), the failure case 1) never should have happened and 2) shouldn't require unintuitive remediation. It's bad design and bad functional-safety analysis. Neither of which fall to the fleet operator or system operator.
  - CorvusCrypto 7y ago
    Yes I agree. And I'm pleading that everyone also recognise the other aspects of these.incidents such as improper basic procedure. It's all of the above. Edit: And remember at the end of the day, these airlines and pilots agreed to fly the plane. Even in the wake of the LionAir incident. At the end of the day, the pilots choose to fly and can say no if they aren't comfortable. And if the answer to this is that there is pressure from airlines to keep flying? We just found another major issue and danger in aviation Edit2: should clarify actually that I agree it's a bad design. Not about the procedures being "unintuitive". If the pilots think the corrective procedures are unintuitive they shouldn't fly any 737 since stab trim systems exist on all 737s and require the same corrective procedure in runaway stab trim.
    - cmurf 7y ago
      Are you a pilot? If so what are your qualifications? Have you read the ET302 preliminary report? In particular have you read page 25, section 2 "Initial findings" last bullet which I quote: The crew performed runaway stabilizer checklist and put the stab trim cutout switch to cutout position and confirmed that the manual trim operation was not working. How can you read that, and say multiple times in this thread "improper procedure"? On what basis? You have no idea how much mental discipline it's taking me, as a pilot, to refrain from ad hominem attack. Your arguments are that bad, they are that willfully contrary to the available facts.
      - 7y ago