yanrair, in another thread,
post #1216 I wrote:
No doubt, a statistical analysis of the chances of these accidents being attributable to random crew error vs random aircraft error is so monumentally in favour of an aircraft malfunction, given the natural experiment that had been performed since 1967, the airworthiness authorities felt they had no choice but to had to act. They simply could could afford a third accident, without a monumental blow to public & pilot confidence, not just in the aircraft, but the entire system of aircraft certification.
Boeing unwittingly performed a very large scale statistical study. Given Boeing's aim was to change as little as possible in the MAX, virtually everything was constant with the exception of the MCAS software (engines and other changes have not been implicated in the accidents). Exactly as you state, same crew, same training, even the same problems & vulnerabilities with the AoA sensor (same part number, willing to be corrected).
That single change has been the software.
So at first blush it is the so we can attribute the MAX accidents to that piece of software. If crews cannot handle that single software change, either the software was wrong, or the industry failed to sufficiently prepare the crews for the design expectations. How many millions of 737 departures have there been since 1967? As far as I can determine, not a single of the
172 hull loss on the 737 has been attributed to a runaway trim prior to the MAX. Two in a very short space of time for the MAX? That is why airworthiness authorities had to act.
The primary blame is the aircraft, secondary to the industry and its race to the bottom minimal investment in pilot training. The cornerstone of the sales pitch for the MAX was a single hour of home ipad study for each pilot, ie no cost at all to most operators.