Some power pilots are quite surprised to learn that glider pilots don't require the services of an accredited engineer to
1) Remove and replace the wings.
2) Remove and replace the elevator
3) Attach all controls, and confirm that they have been properly installed with another person to double check it has been properly done by walking round the glider and resisting the pilot's control imput, holding the ailerons, the airbrakes, the elevator, and the rudder, ( though that is usually left installed during road transport.)
It is important that THESE CHECKS MUST NOT BE INTERRUPTED BY ANYONE OR ANYTHING.
We do this every time we take that beautiful bird out of its box.
A bit sad that all this sort of thing with your standard spam can has to be done by a firm of engineers - and that any pilot with a sense of self-preservation has to double - nay, treble his inspection after such maintenance to make sure they haven't screwed up!
May I recommend, if somebody can name the source, the video of an amazing circuit flown by a Russian airliner, recently reassembled from cannibalised parts, in which the ailerons were installed wrong way round.....they eventually worked out the problem and got it back on the ground in one piece.
Now my personal experience of difficulty with control function was a flight to 18,000 feet in wave. It had rained the night before, the glider had been left outside, rigged, and the aileron tape, at altitude, froze quite solid! So my turns to stay in the wave system were done with rudder alone, quite gingerly, and of course the problem solved when we got lower, and warmer.
There have been a number of cases when a glider elevator has been jammed, usually because some numpty has dropped his camera into the declevity, or in one case a paraplegic passenger's wooden seat cushion jammed full aft movement of the stick. The highly experienced instructor did not express alarm - you NEVER express alarm to a passenger! but their approach was seen to be rather faster than normal.....no harm done. It was his fault for not doing a proper full and free control check before taking off.
So the moral of this narrative is - thoroughly inspect the controls before flying, and if something alarming happens when you are aloft, KEEP CALM AND CARRY ON!
Of course, however, we do wear parachutes.....