"Does anyone have any first or second hand knowledge of a jammed control event"
About 5 years ago, I was working in a hangar and we received a report that one of our aircraft (AW139) which was on a test flight had a control problem and the pilot had issued a Pan call.
The aircraft carried out a run on landing on the airport runway and shut down immediately on landing.
The pilot reported that when flying, he was unable to move the cyclic aft to reduce speed, hence the need for the run on landing and I believe he shut the engines down as soon as the aircraft touched the ground (but I may be wrong on this).
The reason for the jam was due to one incorrectly positioned P-clip just aft of the mixing unit in the cabin roof.
An engine control cable cable had been replaced the previous day and when refitted, the P-clip in question was refitted 180 degrees out which resulted in the pitch rod running just below the P-clip rather than to the side of it.
Although a control check had been carried out both in the hangar and by the pilot on the preflight, no issue was found. However, once the cyclic was fully forward with the collective raised, the locknut on the end of the rod end was able to slip over the P-clip but due to the shape, it wouldn't slip over again when the cyclic was moved forward.
We were very lucky that it was a very experienced pilot at the controls.