If the problem was 'just' MCAS the solution would be in place by now and the Max flying. If you take the view that MCAS was a Bandaid (sticking plaster) on an open wound then the issue is not how to get a bigger or better plaster, but what is neccessary to close the wound. To humble SLF, it seems the fundamental issue is not MCAS but the undesirable aerodynamic characteristics that required MCAS to meet the certification performance standard in the first place. However good the redesigned MCAS is, even with a third AOA probe and associated logic, those characteristics are still there. And if dealing with the failure case requires a procedure that a pilot (however well trained) cannot physically deliver (manual trim), then Boeing either have to play the 'it can't happen' card or make fundamental changes to the mechanical design of the aircraft.
My suspicion is Boeing are trying (and failing) to convince regulators that 'it can't happen' to avoid the massive delay and cost impact of mechanical design changes. And the FAA are more willing to be convinced than EASA, even though the latter (who cannot relish the prospect of a tit for tat certification war with the US) would like to be convinced. Unfortunately, there is no end to this yet in sight.
And once it is sorted, there is still the issue of the relationship between the FAA and Boeing and public confidence: what else did they miss, and have 'they' really fixed it? It will be an interesting test of the Xenophobia of Americans if (as Boeing and the FAA seem to accept) the Max is reintroduced to service in North America but not elsewhere.
By the way, regulatory capture is not just an issue for Americans, Boeing and the FAA: Grenfell Tower proved that beyond all reasonable doubt.
Last edited by SLF3; 23rd Sep 2019 at 12:12.
Reason: Spelling