Originally Posted by
Ian W
The major problem that the 'train in the simulator' group will face is that the failure mode of the Lion Air and Ethiopia crashes no longer exists. If a single AOA vane fails it will not cause MCAS to operate. If MCAS operates it will be for a legitimate high AOA and it will only operate once not repeatedly. So there is no failure mode that can exist with the new software where MCAS will operate as it did before. I would imagine that 737 pilots would be able to cope with a single nose down trim when they are legitimately at high AOA as it will keep the stick back pressure linear. Once the aircraft returns to normal AOA everything is back to normal.
So everyone goes out and buys new simulators to find that there is no MCAS failure mode to simulate. Simulator salesmen will like it - the beancounters not so much - the regulators will be holding the stable door firmly shut despite there being no horse
The root cause problem has not been eliminated, the hope is that it has been made less likely. We do not know why three sensors so far have failed at least Boeing is not telling us. We cannot assume that the failures are random and independent. If for example some console maintenance procedure happens to offset the AOA sensor by exactly twenty degrees then Murphy’s law dictates that at some time that procedure will be performed on both left and right consoles and you will still get a bogus high AoA that both sensors will agree upon.