Not a flight control failure per se but another 'loose'
item jamming a control. Years ago a friend of mine
purchased a used Diamant HBV. He had let me fly it
on several occasions and one day I was flying in especially
turbulent air (lots of rotor). The release knob, wood
and slightly larger than a golf ball, was on a cable
that, for some reason, was very long and there was
probably a foot of slack between the release 'ball'
and the end of the tube that the cable came out of.
Sometime during the flight that 'ball' and cable managed
to wrap itself around the base of the spoiler handle
rather tightly. I did not notice this until in the
pattern to land (800ft AGL) and was unable to pull
the spoiler handle out of the detent (yes, I had 'coasted'
down to that altitude without using the spoilers).
Being in an almost completely prone position and flying
with a side stick (on the right, spoiler handle and
release knob on the left) it was not going to be a
simple matter to untanlge the release cable/knob from
the spoiler handle in the time I had available. I
made a no-spoilers landing which was a non-event, especially
with a 7500ft runway available.

Needless to say, the release cable-to-ball slack was
remedied before the next flight.

JLH