On August 5, 2002, at 0620 Pacific daylight time, an Aero Commander S2R-T34, collided with terrain while making a turn during an aerial application flight near Los Banos, California. The airplane was operated by Vance Aircraft Salvage, Inc., under the provisions of 14 CFR Part 137. The commercial pilot, the sole occupant, was not injured. The airplane sustained substantial damage. Visual meteorological conditions prevailed at the time, and no flight plan had been filed for the local area aerial application flight that originated from a nearby private farm airstrip at 0610. The pilot reported that he had just made his first north-to-south pass over the field to which he was applying chemicals. He then reported pulling up and entering a left turn over hilly terrain along the farm's southern edge in an effort to make a second pass over the field. The combination of the climbing turn and low airspeed was enough to stall the left wing. Shortly thereafter, the left wing contacted terrain. The pilot reported weather the morning of the accident as being clear with light northwest winds at 1-3 knots. No mechanical malfunctions or failures were noted by the pilot prior to the mishap.