MechEngr
What Boeing expected to happen with MCAS did happen.
I don't think Boeing expected the full sequence of events - which is what brought down the aircraft. If it had, the AoA sensor would have carried a "catastrophic" label, which originally it did not.
At this point, who knew about MCAS? Some people in Boeing and the South American airline that had less than half a dozen lines about it in its pilot's handbook. I found this entry quite by chance and introduced it into the gargantuan PPRuNe pair of threads. Basically, the world did not know about MCAS until some time after the first crash. It might be said that Boeing was backwards in coming forwards with that vital information.
The day before the Lion Air crash. Nearly textbook execution of trim problem handling, almost exactly the way the failure mode team expected. Same initial flight deviations, but no one died, nor did any appear to express they felt they might. The pilots wrote it up as annoying.
With respect, that must be an all-time simplification. There may have been a very different outcome if the other skipper hadn't been there. Just the psychological lightening of load by having him input his
observations and thoughts - indeed, to the point of going for his own company's notes. All this must have been of considerable benefit. Yes, they were, in some manner, controlling the aircraft before settling into what must be one of the most illegal flights of the century. Then the write up. Annoying? I know what was annoying - the deaths that might have been avoided if the first captain had not been covering his own hind quarters while minimising a serious disruption of major symptoms. 'How can I write this up to justify carrying on? I know, we'll call the totally uncalled for movement of 47 feet of major flying control as . . . Annoying."
How did the exact same plane with the exact same problem go from controllable to uncontrolled in less than 24 hours? Training and attitude.
When was that almost new AoA sensor changed for an older refurbished unit from Florida? The first
crash had a Sensor with the vane wildly misaligned with its shaft.
The level of chaos on that flight-deck can be compared with the previous day's flight, but I suggest the second flight, the first fatal, was a scenario that had Sully saying, 'That could have claimed me'.
That no one called for grounding the fleet after Lion Air is enough to tell me that no one thought MCAS was a problem.
As I say, Boeing was backwards in coming forward. How long was it before most of the operators in the world even knew what MCAS was? By my count, we're up to two separate instances of silence being deadly.