Trim
Nigel@2677: "An Airbus is slightly different.............it is not "trimming" as such, but aligning THS and Elevator to retain full elevator control."
But "full Elevator control" at an AOA (and airspeed, temperature, pressure etc) presumed by the computer to be correct, along with previous pilot inputs. I thought that was exactly what happened in the case where excessive (and unnoticed?) FCC-directed the THS trim to alter to the point where elevator authority was insufficient.
If the above is incorrect, are you saying that the FCC will correctly notice and interpret unusual variations/combinations in AOA, OAT, pressure, and airspeed over a time period that varies from nearly instantaneous to several seconds, and during that time correctly interpret that a sensor set is beginning to disagree? If you are, the system is pretty smart. But if the system can't interpret all those inputs and correctly categorize them as this or that type of situation where action A is the best, the pilot has lost 5 or 10 or 20 seconds while the computer thought, then annunciated, and then the pilot began to redirect his attention from wherever it was.
I'm getting back to the time involved in the FCC process here. Explanations by posters about the FCC logic chain haven't mentioned time. The system must ignore (or filter) instantaneous changes as either transitory or anomolous, so that means that a certain number of samples over time must be taken for all sensory inputs. Can someone knowledgeable speak to the amount(s) of time the system consumes before it acts in various ways?
RE AOA: Because AOA failure seems to have recurred, do not (or could not) the sensor be mechanically exercised to confirm its movement is free? This need not necessarily involve actual movement but could be forced applied to a pressure transducer. Or is this already built in?