On October 15, 2003, at 1608 central daylight time, an Ayres S2R-R3S single-engine, tailwheel-equipped airplane, N4013Z, sustained substantial damage when it impacted terrain during a forced landing following a loss of engine power near Midland, Texas. The airplane was registered to and operated by Murphree Flying Service, Inc., of Rotan, Texas. The commercial pilot, sole occupant of the airplane, sustained minor injuries. Visual metrological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 137 aerial application flight. The local flight originated from Big Spring Mc Mahon-Wrinkle Airport, near Big Spring, Texas, approximately 1538. According to the 31,000-hour pilot, after completing the first pass of the aerial application on a field, his forward visibility was suddenly obstructed by oil covering the windscreen, followed by a loss of engine power. The pilot attempted to gain altitude, turned to the left (northerly direction), and initiated a forced landing. During the forced landing, the airplane's tailwheel struck a concrete culvert as the airplane crossed a 4-lane roadway. Subsequently, the airplane impacted a telephone pole, a railroad embankment, flipped over, and came to rest inverted. Examination of the turbine powered airplane by an FAA inspector, who responded to the accident site, revealed the main wing spar was bent, and the engine was separated from the airframe. Further investigation of the engine components revealed that a high-pressure steel-braided oil line, which connected the nose engine case to the oil cooler, had ruptured. The rupture occurred approximately 6 to 8 inches from the oil cooler. At the time of the accident, the aircraft had a total airframe time of 2,869.5 hours. The most recent annual inspection of the aircraft was completed on December 15, 2002, with approximately 1,903.6 hours total time on the airframe.