4 ms·

> the aircraft will tend past a certain angle of attack to start nosing into a stall, rather than away from one. Virtually all aircraft will do that, including

> the aircraft will tend past a certain angle of attack to start nosing into a stall, rather than away from one. Virtually all aircraft will do that, including the original 737. Different aircraft do this at different points; provided the pilot is trained for the aircraft, it's not a fundamental problem. The problem for the MAX is they wanted pilots to be able to treat it like an airplane it wasn't.

throwanem 6y ago
https://www.law.cornell.edu/cfr/text/14/25.203 https://www.law.cornell.edu/cfr/text/14/25.203 seems to say otherwise - specifically, that you shouldn't be able to stall a certifiable aircraft unless you maintain a positive (ie nose-up, pulling back) control force "up to and throughout the stall". If that were true of the 737 MAX without MCAS, then MCAS wouldn't need to exist. All you'd need to do to avoid a stall would be to stop pulling back on the yoke, and let the aircraft settle on its own. Stick shakers exist to warn the pilot that they need to stop pulling, and the 737 MAX has one. But evidently the stick shaker isn't enough, because the 737 MAX also has MCAS, which operates to actively deflect the nose back down as the aircraft approaches stall. That shouldn't be necessary. That's the thing that other airframes, including prior marks of the 737, do not do. In those airframes, you don't need to push the nose down to get away from a stall. You only need to stop pulling the nose up. MCAS exists to try to replicate this behavior in the 737 MAX, but that MCAS needs to exist for that purpose is enough to demonstrate that the 737 MAX does not behave that way by default. I agree that the falsely shared type certification, and the consequent lack of training on the MAX's type-unique and dangerous stall behavior without MCAS, is a problem. Where we disagree is that I don't consider acceptable a design that exhibits that behavior at all in the absence of an active control system that can fail or be turned off. Neither do the relevant regulations for certification - I linked them above; they make no mention of an exception for an airframe with something equivalent to MCAS - and neither, historically, has the FAA. Not, at least, until the 737 MAX was itself type-certified, and the way that process played out is itself highly suggestive of significant corruption, in the form of regulatory capture if nothing else.

throwanem 6y ago

https://www.law.cornell.edu/cfr/text/14/25.203 https://www.law.cornell.edu/cfr/text/14/25.203 seems to say otherwise - specifically, that you shouldn't be able to stall a certifiable aircraft unless you maintain a positive (ie nose-up, pulling back) control force "up to and throughout the stall". If that were true of the 737 MAX without MCAS, then MCAS wouldn't need to exist. All you'd need to do to avoid a stall would be to stop pulling back on the yoke, and let the aircraft settle on its own. Stick shakers exist to warn the pilot that they need to stop pulling, and the 737 MAX has one. But evidently the stick shaker isn't enough, because the 737 MAX also has MCAS, which operates to actively deflect the nose back down as the aircraft approaches stall. That shouldn't be necessary. That's the thing that other airframes, including prior marks of the 737, do not do. In those airframes, you don't need to push the nose down to get away from a stall. You only need to stop pulling the nose up. MCAS exists to try to replicate this behavior in the 737 MAX, but that MCAS needs to exist for that purpose is enough to demonstrate that the 737 MAX does not behave that way by default. I agree that the falsely shared type certification, and the consequent lack of training on the MAX's type-unique and dangerous stall behavior without MCAS, is a problem. Where we disagree is that I don't consider acceptable a design that exhibits that behavior at all in the absence of an active control system that can fail or be turned off. Neither do the relevant regulations for certification - I linked them above; they make no mention of an exception for an airframe with something equivalent to MCAS - and neither, historically, has the FAA. Not, at least, until the 737 MAX was itself type-certified, and the way that process played out is itself highly suggestive of significant corruption, in the form of regulatory capture if nothing else.