On August 24, 1996, at 1554 hours Pacific daylight time a Katana DA20-A1, N474B, taxied into two parked aircraft in a non-movement area at the South Lake Tahoe, California, airport. The aircraft sustained substantial damage; however, neither the private pilot nor his passenger was injured. The aircraft was rented from American Aviation Flight Schools, Inc., for a personal flight when the accident occurred. The flight originated at the Sonoma County Airport, Santa Rosa, California, about 1138 with a stopover in South Lake Tahoe. Instrument flight conditions prevailed and a VFR flight plan was on file. The pilot reported that when he attempted a right turn from parking, his right hydraulic brake did not produce the braking action he expected. During the attempt, the aircraft turned wide and struck the spinner of a Cessna 182, N3161S, with its left wing tip. As it continued in the turn, the aircraft next struck the propeller of a Piper PA-24-250, N7604P, with the landing light located on the leading edge of its left wing. After the second impact, the aircraft yawed about 90 degrees to the left until its spinner struck the left wing of the Piper. After the accident, the pilot measured the displacement from the taxiway centerline to the spinner of the parked Piper as 22 feet 6 inches. The wing span of the accident aircraft was reported by the pilot to be about 35 feet. According to the operator, the aircraft had undergone an annual and a 100-hour inspection the day before the accident. The pilot stated that he believed he was the first person to rent the aircraft after the completion of the inspection. On August 30, 1996, an FAA airworthiness inspector examined the Katana's brake system. He reported that the brakes operated properly. He also noted that the Katana requires the use of differential braking to steer the aircraft during ground taxi operations. The pilot was issued a private pilot certificate on August 19, 1996.