Well, I could be wrong. I remember reading in what I considered an authoritative source that MCAS was needed to preserve the type cert, not to comply with the FARs. But I can't find the reference right now.
If it's true that the Max can't be certified at all without MCAS that would be a whole nuther kettle of fish.
The specific issue seems to be the sentence: "No abnormal nose-up pitching may occur." The 737 MAX engines cause abnormal nose-up pitching at high enough AoA, if their pitch up moment is not compensated somehow.
Here is the page that first led me to that section:
I haven't read that there is an abnormal pitch up, which would directly contradict (a).
Nevertheless, I have a very serious problem about any kind of computer compensating for the lack of either static or dynamic stability as required in FAR 25. Those stability requirements are there to ensure an intrinsic aerodynamic behavior of the airplane. The instant your augmentation fails for any reason, including electrical failure, now your airplane is legally not airworthy and your pilots are legally not certified to fly it, because their training is predicated on that augmentation always being available.
That is why I think the central issue is not a violation of airworthiness standards regulations. If that were true, it seems like that would be known already, and there'd be hell to pay. Clear cut and dried.
Whereas it's a more complicated matter when it comes to type certifications. There are many nuances including the little detail that the FAA gets to decide the conditions under which a (new) aircraft type certificate is required (or not), and what kind of mitigations are required (or not). Only if the aircraft gets a new type certificate, is a pilot required to have a type rating and the commensurate training and currency requirements that go with it. I still think that's what all of this (being the problem with the airplane and the on-going delays) is about, and negotiating this with all the other civil air authorities.
I bet Brazil and EU regulators have resisted a sweep it under the carpet approach. And I also bet that somewhat recently the regulators, even at FAA, got to a point where they decided they needed to see the NTSB report. Otherwise, they could plausibly roll out a "fix" that doesn't adequately fix the problem per NTSB. And if that happened, while I could see FAA paper over it these days, I'd expect other civil aircraft authorities say no. And plausibly reground the airplane until it does get a proper fix.
> That is why I think the central issue is not a violation of airworthiness standards regulations. If that were true, it seems like that would be known already, and there'd be hell to pay. Clear cut and dried.
The airworthiness regulations are tested in flight, so if Boeing flight tested a 737 MAX with MCAS active and it passed, there would be no violation. The regulations do not say the airplane has to pass the flight test with no automated compensation systems active.
> it's a more complicated matter when it comes to type certifications
Yes, the judgment of when a new variant is different enough that it requires a new type certification is not cut and dried. That might come into play if the FAA's judgment of whether the 737 MAX with MCAS should have required a new type certification were the question; but it isn't. The question is what it would take to make the 737 MAX without MCAS qualify to fly. At this point I don't think anyone believes that will happen without a new type certification for the 737 MAX; the question is whether even with a new type certification it will be possible to convince the FAA that the plane qualifies to fly.
If it's true that the Max can't be certified at all without MCAS that would be a whole nuther kettle of fish.