Originally Posted by
hec7or
So, in the event of an AoA sensor failure a "system" induced stab trim runaway occurs...which admittedly does have memory items.
Unfortunately this MCAS intervention is not a classic "runaway stabiliser", it stops for 5 seconds after trim application, then activates again. You could see how a crew dealing with an unreliable airspeed could end up with the MCAS progressively ratcheting in forward trim, sporadically counteracted by pilot back trim, or even holding a significant backstick force against the MCAS.
Imagine dealing with what you believe is the "bigger problem" (UA) and the elevator & trim act in a unexpected manner (due to the undocumented MCAS), that is what this crew probably faced. Would any of us have recognised
we actually had a flight control system problem?
Ultimately, is is possible that the actual cause of this accident will turn out to be an undocumented flight control issue.