The pilot, who is an approved AUF instructor, was conducting a solo test flight, following complaints by a student that directional control was more difficult than normal. During the takeoff run a rudder lever arm collapsed, directional control was lost, and the aircraft collided with a fence. It was likely that the directional control problems originally reported were related to the rudder lever arm being bent. The reason for the bending was not established, but the lever had evidently been weakened to the point where it failed during the attempted takeoff.
