On July 12, 2005, at 1730 central daylight time, a Rockwell S-2R, N4232X, piloted by a commercial pilot, was substantially damaged when it struck a guy wire while completing an agricultural application pass near Guelph, North Dakota. The flight was operating under 14 CFR Part 137 without a flight plan. Visual meteorological conditions prevailed at the time. The pilot sustained serious injuries. The local agricultural application flight departed Oakes Municipal Airport (2D5), Oakes, North Dakota, approximately 1645. In his written statement, the pilot reported that prior to the application passes he circled the field 3 times "checking for obstructions." He noted that he observed power lines running along the north end of the field and he decided to fly parallel to the lines. He stated that during the last pass of the field, adjacent to the power lines, he did not see the guy wire attached to the second to last set of power line poles. He reported that the right wing struck the guy wire, severing about 4 feet of the wing. He noted that the airplane "jerked" to the right and pitched upward. He reported: "At this point I was underneath the wires, [sliding] sideways through the air. I fought to get the nose level. Then the nose pitched down and I [impacted] into the slough in about 3 feet of water." The pilot stated that there were no problems with the airplane prior to the accident. He also reported clear skies and "unlimited" visibility at the time of the accident.