On August 25, 2002, at 1000 central daylight time, an Air Tractor AT-402A, N9032K, operated by Bakke Flying Service, contacted power lines during an aerial application flight in Cherokee, Iowa. The airplane then contacted the terrain while attempting to land at the Cherokee Municipal Airport (CKP), Cherokee, Iowa. The commercial rated pilot was seriously injured. The airplane received substantial damage. The Title 14 CFR Part 137 aerial application flight was operating in visual meteorological conditions without a flight plan. The flight originated from CKP at 0830. The pilot reported he was making a swath run along a set of power lines that ran north and south through the middle of a field when the airplane contacted another set of power lines that ran east and west along the north edge of the field. The top 10 inches of the vertical stabilizer and the rudder separated from the airplane. The pilot reported that when the rudder separated, the rudder pedals were "pulled tight against the hopper." He stated that he could no longer reach the rudder pedals with his feet and he was not able to free them up. He reported that he had no rudder control and "some" aileron control. The pilot reported the airplane was heading toward the airport, so he continued in that direction at tree top height. He reported he contacted the Unicom at the airport, informed them of what happened and requested that they call the fire department and an ambulance. The pilot reported that about one-half mile from the airport, he pulled the power back to 1,000 pounds of torque and the airplane began to bank to the right. He reported that he was unable to control the bank with the ailerons. According to the pilot, the airplane then banked to the left, the nose pitched up, and the airplane "rolled over on its back." He reported the nose then dropped and the airplane descended to impact with the ground.