Originally Posted by
fgrieu
Since normal activation of MCAS is a normal event, and essentially undistinguishable from an autotrim, it would not have been reported.
There is no such thing as "normal activation" of MCAS, which (by definition) was intended "to provide consistent handling qualities in unusual flight conditions".
Nor is it "undistinguishable from autotrim" - the latter can be arrested by the control column microswitches, MCAS can't.
Also, I guess that MCAS was intentionally tested (and activated) at least in Boeing test flights, and perhaps in certification flights, which would make the statement demonstrably false.
The OP was clearly referring to deployment of MCAS in revenue service, not during certification. There have been no documented instances of the former, other than on the accident aircraft.