On September 2, 1998, approximately 1740 mountain daylight time, an Air Tractor AT-502B, N50620, was destroyed by fire following an emergency landing near Portales, New Mexico. The commercial pilot, the sole occupant in the airplane, received minor injuries. The airplane was owned/operated by King AG Leasing Inc. under Title 14 CFR Part 137. Visual meteorological conditions prevailed for the local aerial application flight which originated approximately 25 minutes before the accident. No flight plan had been filed. According to the pilot, he had flown 7 or 8 east-west passes over a cotton field, and was flying westbound into the sun (266 degrees, 19 degrees above the horizon). He said that there was a circular pivotal sprinkler extending from the northern center of the field to the southeast. He was adjusting his onboard global positioning system (GPS) and when he looked up, "I was right at the sprinkler." He said that he "immediately pulled up elevator but still struck the sprinkler." The pilot stated that a fire broke out in the right hand forward part of the cockpit and he knew he had to get out as soon as possible. The pilot reported that the sprinkler impact had separated the left main landing gear and when he landed in the adjacent peanut field, the airplane ground looped to the left. He further stated that when the airplane came to rest, "I opened the left cockpit door and bailed out as quick as possible." The pilot received second degree burns on his right hand and arm, and first degree burns on his face.