Methods for altitude changes

Just go look it up! writes:

Hmm... Is it a true statement though? The King autopilots (and the
S-Tec range AFAIK) both are designed such that they use pitch servos
to reposition the control surface (elevator or stabilator) to affect
a change (climb, descent) and have inbuilt feedback generators to tell
the trim servo to actuate such that it removes the load from the
surface at its new position. That seems to be at least two systems
who's basic design incorporates a methodology to actively relieve
control pressures.

Relieving control pressure is still not the purpose of the autopilot, though.
It merely uses that as a means to an end.

If autopilots were really intended to relieve control pressures, then they
would not hold altitude or heading. Instead, they would act to keep the
controls in whatever position you last put them in, irrespective of altitude
or heading. I don't know of any autopilot that does that. The closest
approach is the control-wheel steering feature of some AFDS systems on large
transport aircraft, but apparently pilots don't use those features very often,
and it's still based on maintaining something other than control pressures.

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