On October 13, 2004, approximately 1650 central daylight time, an Air Tractor AT-301 single engine, tailwheel-equipped, agricultural airplane, N8886S, was substantially damaged following a loss of control during landing near Coahoma, Texas. The commercial pilot, the sole occupant, was not injured. The airplane was registered to and operated by ANF Air Service Incorporated of Garwood, Texas. Visual meteorological conditions prevailed and a company flight plan was filed for the 14 Code of Federal Regulations Part 137 agricultural flight. The local flight originated from Big Spring Airport (BPG) near Big Spring, Texas, approximately one hour earlier. According to the 3,600-hour pilot, while spraying cotton for boll weevil eradication, the airplane developed a vibration. Thinking that the spray pump was about to sling a blade, the pilot elected to make a precautionary landing on a gravel road. The pilot reported that after touch down, he was unable to maintain directional control and departed the right side of the road. The right wheel then contacted a dirt embankment and the airplane turned sharply to the right, resulting in the collapse of the left main landing gear. The airplane came to rest, upright, in a ditch. An inspector from the Federal Aviation Administration (FAA) evaluated the damage to the airplane. He reported that the fuselage was buckled and that both wings were twisted. At 1653 central daylight time, the weather observation facility at Midland International Airport (MAF) near Midland, Texas, which is located approximately 50 miles west of the accident site, reported the wind from 140 degrees at 6 knots, visibility 10 statute miles, clear of clouds, temperature 72 degrees Fahrenheit, dew point 53 degrees Fahrenheit, and a barometric pressure setting of 29.92 inches of Mercury.