HISTORY OF FLIGHT On May 12, 2007, about 0900 mountain daylight time, a Piper PA-25-235, N7739Z, departed controlled flight and collided with terrain during a low pass several miles west of Delta, Utah. The airline transport pilot, who was additionally the owner, was operating the airplane under the provisions of 14 CFR Part 137. The pilot, the sole occupant, was fatally injured. The airplane was destroyed. The local aerial application flight departed at an unknown time from an airstrip in Delta. Visual meteorological conditions prevailed, and a flight plan had not been filed. A sheriff's deputy interviewed a witness immediately following the accident. He reported observing the airplane maneuvering northbound. At the end of the field it began to climb and made an abrupt bank to the right in a nose high attitude. The airplane then dove toward the terrain and erupted into flames. A National Transportation Safety Board investigator spoke with the property owner who the pilot was performing work for. He stated that the night prior to the accident both men drove around the 40-acre field that was to be sprayed. The morning of the accident, the owner again spoke with the pilot and observed him to be cheerful and well rested. The owner noted that the pilot would be spraying in a north-south direction. He further stated that the pilot had been performing spraying operations on his fields for 2 years. The accident flight was the first time the pilot had sprayed that specific field. PERSONNEL INFORMATION. A review of Federal Aviation Administration (FAA) airman records revealed that the pilot held an airline transport pilot and commercial certificate. The pilot was issued a first-class medical certificate on June 20, 2007, with the limitation that he must wear corrective lenses. The pilot's personal flight records were not recovered. On his last application for a medical certificate the pilot reported a total flight time of 14,500 hours. A Safety Board investigator spoke with the pilot's wife with regards to his flight activity. She stated that he was a first officer in a Boeing 737 and flew agricultural operations in his spare time. He began flying such operations about 5 years prior to the accident. She recalled that he had been a pilot for over 30 years and had flown the same make and model as the accident airplane about 200 hours. AIRCRAFT INFORMATION No maintenance records were located for either the airframe or engine. The pilot's family members stated that they searched his residence and vehicles and could not locate any records relating to maintenance on the aircraft. METEOROLOGICAL INFORMATION The closest weather observation station was located in Delta, which is located 4 miles east of the accident site. At 0840, the station was reporting scattered clouds at 12,000 feet above ground level (agl) with surface winds from 160 degrees at 6 knots. The hourly observations before and after the accident were similarly reporting clear conditions with winds less than 6 knots. No unusual meteorological phenomena were reported by the station or observed by witnesses to the accident. WRECKAGE AND IMPACT INFORMATION The main wreckage was found at the approximate global positioning system (GPS) coordinates of 39 degrees 19 minutes 59 seconds north latitude by 112 degrees 38 minutes 46 seconds west longitude. The accident site elevation was about 4,600 feet mean sea level. An aviation safety inspector from the FAA responded to the accident site and examined the wreckage. The FAA inspector reported observing evidence of propeller blade deformation that he opined was consistent with the engine producing power at impact. Based upon the observed ground scar and damage to the airframe, he stated that the airplane appeared to have impacted the dirt field in a nose-low attitude, almost vertical. Additionally, an imprint of both wings was noted in the soil giving the appearance that the left wing impacted first. The cockpit area and empennage were consumed by fire. The FAA inspector additionally reported that fragmentation of the wreckage prohibited an examination of the flight controls. He accounted for all major components of the airplane at the accident site. According to the property owner, the airplane came to rest about 800 to 1,000 feet north of the field perimeter that the pilot was spraying. The orientation of the wreckage was consistent with the pilot being in a course reversal turn back toward the field at the time of impact. The wreckage was almost in the middle of the field, located just slightly on the westerly side of the field. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed by the Millard County Sheriff Office of the Medical Examiner. The autopsy report concluded that the death was the result of injuries sustained in the accident. The FAA Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, conducted a toxicological examination. The report was negative for cyanide, volatiles (ethanols), carbon monoxide, and drugs. TESTS AND RESEARCH A Safety Board investigator reviewed the airplane's Major Repair and Alteration documents (FAA Form 337). An entry indicated that the airplane was equipped with a Satloc global positioning system (GPS) recording device. The extensive thermal damage to the airplane prohibited investigators from obtaining any recorded information.