flyhardmo, thanks, some interesting points.
The THS operation in manual flight is understood, but how does the AP involve the THS; AP command of autotrim would be logical to relieve the control system effort as discussed above.
It is assumed that the THS movement was due to the AP’s response to the change in pitching moment – opposing the overriding control input and/or the thrust increase, with possible further input due to configuration change. However, with FBW why would a stick input be used to control the aircraft (to oppose the AP) when the AP is engaged, cf Airbus.
If the override stick input has no control with AP engaged, then the THS change was probably due to thrust / configuration change, which leaves the potential for a residual out-of-trim condition when the AP disengages (disparity between stick position and control surface position) until “the control system transitions the control surface commands from those of the autopilot to those of the flight crew”, i.e. a period of readjustment with the pilot not totally in control, which is probably not significant … … unless there is a large change in pitching moment – woops.
Re the disconnect force; the description suggests that there is a ‘hole’ in the logic. If the crew override the AP following a down grade from a high integrity approach mode (cat 3), in circumstances where the AP does not disengage, then the overpower-disconnect logic changes / is non-existent.
Alternatively, (via Chris) do opposing stick inputs invalidate the overpower-disconnect logic; or does the disconnect description only relate to a jammed (blocked) stick, which may not apply with AP engaged.
What control forces (and movement) are fed back to the stick with AP engaged?