On July 16, 2004, at 1840 central daylight time, an Aero Commander Callair A-9B, N7798V, operated and piloted by a private pilot, received substantial damage on impact with terrain and a utility pole during an emergency landing approximately 3 nautical miles northwest of Norton, Kansas. The pilot reported that he had an in-flight fire in the cockpit. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 aerial application flight was not operating on a flight plan. The pilot sustained serious injuries. The local flight originated from Norton Municipal Airport, Norton, Kansas, about 1830. According to the on-scene Federal Aviation Administration (FAA) inspector, a witness stated that the airplane had about 100 gallons of chemical in the hopper and full fuel at the time of departure. Witnesses reported that the airplane was descending from a low altitude when it impacted a milo field, sliding 50-60 yards before impacting a powerline pole and bursting into flames. The airplane came to rest approximately 45 degrees to the left of its initial path after impacting the powerline pole. The pilot egressed from the airplane and sustained third degree burns. The 1970 Aero Commander Callair A-9B, serial number 1551, airplane accumulated a total time of 4,340 hours. The airplane was powered by a Lycoming IO-540 engine, serial number L-7741-48. Airplane logbook records show that the last engine inspection was an annual inspection dated April 14, 2004, at a tachometer time of 1,251.1 hours. Inspection of the airplane by the FAA inspector revealed evidence of fire aft of the left hand side of the engine cooling baffling, above the fuel injector pump part number 75567. The inlet fuel line, part number 18586, a steel braided flexible hose from the fire wall to the fuel pump showed evidence of fire. The end of the fuel line that attached to the fuel pump was burned through and the fire sleeve, part number 18685, was charred with patches of white ash at the end of the fire sleeve. The end of the line that attaches to the firewall exhibited a similar condition. The other lines of similar construction in the area of the fire were not burned through. The operator had not been issued a 14 CFR Part 137 certificate.