@ NigelOnDraft...
So that I understand this "autotrim" feature that keeps coming back in many conversations...
Do I understand this feature correctly as a pitch trim that is activated automatically whenever an extended pitch input (up or down) is commanded through the sidestick?
In other words if I command a pitch up from the sidestick, it trims in a nose up to relieve back pressure on the elevator not unlike when you fly a conventional aircraft in manual when using the electric trim or basically the same way an aircraft on AP would trim itself?
If I'm correct in my assumption as stated above? If so what is the big deal behind this feature on the Airbus?
Assuming the THS is trimming a nose up attitude because you are pulling on the sidestick, wouldn't the reverse also be true… that with a nose down input the THS would trim nose down?
Assuming you are in cruise at FL370 in an Airbus 320 and all is working properly, you then encounter some mountain wave turbulence or something similar to it, what usually happens at first in an increase in speed with a tendency in an increase in altitude usually compensated by the AP.
In the above scenario in a very conventional aircraft with a basic AP without AT, if left unchecked and if the power is not reduced, the aircraft may overspeed but it should hold altitude. In an aircraft with AT, the FADECs should automatically reduce to a power setting as to avoid overspeed.
However it seems from reading on here that the Airbus might want to pitch up to avoid overspeeding, is this correct? At what point will the Airbus reduce power to keep it within the normal parameters?
Back to AF447 and the THS being full nose up. If the pilot would have just inputed a full nose down on the sidestick, wouldn’t the THS trimmed nose down too?