On April 23, 1996, at 0825 hours mountain standard time, a Bellanca 7KCAB, N333JS, collided with a back hoe after landing on runway 12 at the Avra Valley airport, Tucson, Arizona. The airplane sustained substantial damage and the certificated private pilot and passenger were not injured. The airplane was being operated as a personal flight. The flight originated from the La Cholla Airpark in Tucson about 0755 hours. Visual meteorological conditions prevailed at the time. The pilot indicated he entered the downwind leg of the airport traffic pattern and noted the windsock was indicating calm winds. He completed the normal rectangular traffic pattern with no indications of the wind conditions changing. He also stated that a gust of wind from the west raised the right wing, allowing the airplane to drift left as it touched down. The pilot immediately applied right aileron and rudder. The wings returned to level and the airplane continued to drift left towards the left shoulder of the runway. He added power and then removed it when he saw a back hoe adjacent to the runway in his path. He was attempting to steer the airplane clear with the rudder pedals when the left wing collided with the back hoe. The pilot stated that the back hoe was parked with the engine running unattended about 20 to 30 feet from the runway's edge. The pilot remained with the airplane for several hours after the accident. During that period he noted the windsock would indicate calm winds with periodic shifting gusts above 15 miles per hour.