On November 28, 1999, about 1000 Eastern Standard Time, a Stinson 108, N89F, was substantially damaged during landing at the Grove City Airport (29D), Grove City, Pennsylvania. The certificated flight instructor (CFI) and student pilot/owner received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the instructional flight conducted under 14 CFR Part 91. The CFI stated that he and the student pilot departed 29D about 0900, for a "local training flight." An hour later they returned to the airport to make a full stop landing on Runway 28, a 4,500 foot long, 75 foot wide asphalt runway. According to the CFI, "there was no apparent cross wind drift" and the student pilot was "tracking well on the approach." At the point of touchdown, the airplane "sharply, and suddenly veered to the left." The CFI stated that they then lost directional control of the airplane. The airplane traveled off the side of the runway, impacted the opposite side of a 15 foot deep ravine, and came to rest 200 feet from the centerline. The CFI reported there were no brake pedals on the right side of the airplane, and the parking brake knob was located on the "far left panel," which was blocked by the student pilot. The student pilot reported that this was his second flight in the accident airplane. He stated that he and the CFI had flown for about an hour when they returned to the airport for a full-stop landing. The student pilot reported there was "little wind" on the day of the accident, and his landing on Runway 28 was "perfect." During the landing rollout, the CFI said, "I got it" and the student pilot then relinquished the controls to him. Immediately after the CFI took over, the airplane veered off the runway and impacted a ditch, at 40-50 mph. A Federal Aviation Administration (FAA) Inspector examined the airplane while it was in the ravine. He stated the fuselage and instrument panel were buckled, one propeller blade was bent backwards 45 degrees, and the engine mounts and firewall were damaged. The FAA Inspector further examined the airplane after it was removed from the ravine, and reported no pre-impact mechanical deficiencies. The CFI reported 2,113 hours of total flight experience, and about 400 hours of total tailwheel experience, 5 hours of which were in the make and model of the accident airplane. The student pilot reported 3 hours of total flight experience, all of which were in the accident airplane. The winds at an airport 19 miles away, at 0955, were from 260 degrees at 4 knots.