FCeng84, thanks for the very useful aerodynamics lessons. Joining others, we may be jumping ahead somewhat in our assumptions about the Ethiopian and indeed Lion crash but I personally believe that having now turned-over the MCAS stone the issue must be addressed, regardless of it's (non) role in recent accidents. Some (random) questions/observations:
Before the pilot world knew about MCAS, how would an MCAS failure have been manifested? Should it have been an 'MEL' Item? In other words, if it was not visible/known to pilots, how would anyone have known the system was working? Consequently, was it just looked upon as a sticking plaster necessary to get over a certification requirement and something that didn't need to be monitored or even in place for real world operations? I'm reminded of VW diesel engines and emission tests.
What was the rationale behind only using a single data source to the MCAS?
I think it has already been addressed but, does the flight regime mean that MCAS will activate at/before/about the same time as the stick shaker?
How did Boeing come to the conclusion that a 5 second pause after pilot trim inputs was the MCAS reset period?