EridanMan writes:

Minor Harmonic oscillations in flights are a natural byproduct of the
dynamic stability of modern aircraft. The Autopilot has no part in
it.

Do these oscillations cause control surfaces to move by themselves? Are they
asymmetrical?

When the oscillations are on the Longitudinal axis, they are called
phugoid oscillations, I'm not sure if there is a similar term for the
roll equivolents ...

Dutch roll and spiral come to mind, although they are not limited exclusively
to the roll axis.

No MX... it has nothing to do with the autopilot...

If the control surfaces are moving, either the pilot or the autopilot is
acting upon them. If the corrections are asymmetrical, this would tend to
exclude the hypothesis of harmonic oscillations. Also, roll harmonics often
extend over periods of minutes in large aircraft and would not be obvious just
by watching the wing outside the window.

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