The original 737 wasn't broken-by-design in the way the Max is. The Max _requires_ software kludges to paper over its deliberate mistakes; that's very different from just having a few bugs to work out in a fundamentally sound design.
> MCAS was devised to fulfill an airworthiness certification condition in 14 CFR 25.173 and 14 CFR 25.175. In high angle-of-attack (AoA) flight configuration, it is required that stick force/g (the stick force necessary to produce (hold) an incremental normal acceleration of 1g) and stick movement/g (ditto mutatis mutandis) must increase (or at least not decrease) with an increase in AoA (thanks to Clive Leyman for this formulation). I understand that in flight test, in which “wind-up turns” were conducted (a turn with increasing angle of bank; an increasing angle of bank means ceteris paribus increasing AoA), this condition was not fulfilled.
-- https://abnormaldistribution.org/index.php/2019/04/30/ieee-s...
And also to stop the plane dropping out of the sky!
@HPsquared “.. The plane is perfectly stable without MCAS ..”
NO, no, no it isn't .. doesn't matter how many different ways you re-arrange the word salad. MCAS is a software kludge to compensate for an unstable airframe
The implementation is certainly not "elegant". It's like this random batch job that triggers when some conditions are satisfied and does its own thing without regard for anything else, sure. Not integrated with the auto-pilot, does not display anything in the panel.
We have plenty of aircraft (even though most are military) which are aerodynamically unstable, and require fly-by-wire software to even be flyable. We don't think those are kludges. That's not too far from what Boeing has to do.
It could have been either a fancier fly-by-wire software in the Airbus philosophy that wouldn't let pilots exceed parameters(retrofitting it might have been a challenge, and possibly even more dangerous). Or it could be this non-elegant solution that behaves like an old-school stick pusher. Both could have worked.
The problem is that they did this while trusting a single sensor. And not informed anyone.
Airbus had a crash because their fly by wire averaged the input from both yokes vs doing what Boeing does which is to allow both to feel that the other is pushing on the yoke and the pilots where not trained to understand that.
An interesting question is going to be as to what happens elsewhere in the world; I'd be intrigued to see if Boeing ends up certifying the 737 MAX with MCAS as an optional feature with additional difference training required, as some things mentioned suggest that it's not implausible that this will happen.