On July 12, 2002, at 2030 Pacific daylight time, an Ayers S2R-T34, N4020Y, sustained a separated left main landing gear during the takeoff ground roll at the Newman Ranch Strip, 5 miles east of Firebaugh, California. After the landing gear separated from the airplane, the airplane veered off the runway. The airplane, owned and operated by Thiel Air Care under the provisions of 14 CFR Part 137, sustained substantial damage. The commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed for the local area aerial application flight that was originating at the time. No flight plan had been filed. In a written statement submitted by the pilot, he reported that approximately 200 feet into the takeoff roll, the left main gear collapsed. The left wing tip and the propeller struck the ground. This was followed by the airplane pivoting to the left and going into a ditch. As the airplane impacted the opposite side of the ditch, the right main gear was forced under the airplane. The airplane came to rest on its belly. The pilot shut the engine down manually. A Federal Aviation Administration airworthiness inspector from the Fresno, California, Flight Standards District Office examined the airplane. He reported that the ear that secures the left main gear strut to the fuselage structure had fractured and separated, allowing the left gear strut to separate from the fuselage. The inspector examined the 30-foot-wide airstrip in the area used by the pilot for the takeoff ground roll. He located a chuck hole in the asphalt pavement that was 15 feet long by 3 feet wide and that had a maximum depth of 3 inches. At the northern end of the chuck hole (closest to the airplane point of rest), a 2.5-inch-deep lip was noted in the hole wall. Marks and transfers consistent with the landing gear and the fuselage contact to the pavement were noted just beyond this chuck hole.