On December 11, 1998, at 1600 hours mountain standard time, a Piper PA-28R-200, N9320N, veered off the right side of runway 6R and struck a ditch on the landing rollout at Ryan Field, Tucson, Arizona. The airplane, operated under 14 CFR Part 91, sustained substantial damage. The flight instructor and the private pilot/owner were not injured. Visual meteorological conditions existed for the local instructional flight that had originated at 1530. No flight plan was filed. In the instructor's written statement he reported that the purpose of the flight was to conduct a proficiency check for the private pilot. He stated that he was demonstrating a soft field landing. The instructor reported that the airplane was in a nose-high configuration and he was not applying brakes (as brakes are not available on the right side of this model) on the landing rollout. He stated that he felt a "sudden abrupt veering to the right - unable to get longitudinal control (no brakes on right side of arrow)." The airplane veered off the runway, the gear collapsed, and they exited the airplane without injury. No mechanical anomalies were noted with the airplane or engine by the instructor pilot. In a subsequent interview with a Federal Aviation Administration (FAA) inspector, the instructor and son of the pilot reported that the pilot had lost control of the airplane after landing, and that the instructor was not quick enough to respond to the situation. The instructor felt that the pilot panicked and continued to apply incorrect inputs into the steering and brakes to control the airplane. An FAA inspector reviewed the maintenance logbook and found no discrepancies. He further examined the landing gear and braking system, and found no abnormalities that may have contributed to the accident.