I think many of those on Pprune are not only interested in the WHAT but also the WHY. Why did Boeing design it this way and communicate it this way.
A real life option of what might have happened in the WHY field is that during design and test they stumbled on some issues in the envelope with respect to stall in certain regimes. As a designer/manufacturer, WHATEVER you run into, you don't want to 'break the Type Certificate'. Breaking the TC is not only very costly but will also cause substantial delay. (I change the sequence of the items compared to what A Squared posted earlier in a reply to Silverstrata - changed it because it is meaningful). So they generated a number of possible solutions. They selected the 'MCAS' solution for implementation which did not require breaking the TC. What we don't know, next to knowing surprising little about MCAS at this stage, is how it was tested and under what assumptions and rules. And if anyone rang a bell (would surprise me if not, but ..).
A proper solution requires proper communication to all stakeholders, so not only to pilots, trainers but also to maintainers. It is hard to understand why that communication was not up to the expected level. Especially as a number of consequences of the MCAS design decision will appear counter-intuitive to quite a few people.
In another 737 case I was surprised that 737's did not have a certain well proven system. The published reason for that was documented as being to stop short from breaking the TC. Will try to dig up that information.
When there are answers on the issues above, it would not surprise me if there will be other questions that will zoom in on the history of the envelope issue. Was it there before the MAX, and how much margin was there for earlier solutions.
Last edited by A0283; 14th Nov 2018 at 11:25.