You may find the following NTSB accident reports interesting, they are similar to, but not necessarily what I would call “jammed controls”:
LAX04LA254 - While performing a maintenance check flight, the collective down lock engaged, which resulted in an uncontrolled descent and collision with terrain.
NYC97LA058 - When the pilot raised the collective, the helicopter lifted about 2 to 4 feet above the ground, and then began to roll left. The pilot attempted to correct for the left roll; however, the helicopter did not respond and the main rotor blades struck the ground.
The following 2 accidents are an apparent jamming of controls due to incorrect configuration of the helicopter hydraulic system:
CEN14IA329 - Immediately after takeoff, the helicopter started a counter-clockwise yaw. The pilot stated that the anti-torque pedals were locked in the neutral position and felt jammed.
CEN14FA193 - The pilot reported that the (antitorque) pedals felt jammed or locked in the neutral position.