On March 23, 2001, about 1550 hours mountain standard time, a Cessna 305A, N5188G, owned and operated by the front seated pilot, ground looped during landing rollout on runway 04 at the Winslow-Lindbergh Regional Airport, Winslow, Arizona. Visual meteorological conditions prevailed and no flight plan was filed. The airplane was substantially damaged. Neither the front seated pilot nor the rear seated certified flight instructor was injured. The instructional flight was performed under 14 CFR Part 91, and it originated from Needles, California, about 1.4 hours earlier. The certified flight instructor (CFI) reported that the front seated student held a private pilot certificate, but he had not received an endorsement to fly conventional gear airplanes. The private pilot had just purchased the airplane. He was in the process of flying the airplane to his Annapolis, Maryland, home with the aid of the CFI. Regarding the accident, the CFI reported that the private pilot's landing was normal. However, seconds after touchdown the airplane started turning slowly to the left. The CFI applied rudder pressure for the correction, but was unable to move the right rudder more than 3 or 4 inches. The left turn continued, and the CFI stated that he shouted for the pilot to "get off the controls." The CFI subsequently reported that he pushed "very hard" on the right rudder and applied heavy braking in an effort to stop the turn to the left. However, "the right rudder would not move regardless of the effort or force applied. The turn to the left continued to accelerate. The right wing tip touched the ground and the right wheel separated from the strut at the axle." The CFI discussed with his student the sequence of events that led up to the accident, and he made several observations regarding the student's physical appearance. In pertinent part, the CFI reported that his student has a large physical stature; his shoe size is 14. The CFI and student agreed that during the landing rollout, the student's left foot had slipped off the rudder pedal. It had become jammed between the top portion of the pedal and the console. This resulted in restricting the rudder pedal's movement and the CFI's inability to take corrective action to preclude the loss of control.