On 1 May 2006, at 0800 central daylight time, a single-engine Air Tractor AT-802A agricultural airplane, N8504T, was substantially damaged during a forced landing following a reported loss of engine power near Jasper, Texas. The commercial pilot, sole occupant of the airplane, sustained minor injuries. The airplane was registered to Ag Pilots, Inc., of Onalaska, Texas, and was being operated by Thrash Aviation. Visual meteorological conditions prevailed for the aerial application flight for which a flight plan was not filed. The local flight originated from the Jasper County Airport (JAS) at time unknown. The turbine powered agricultural airplane was loaded with a payload of 5,500 pounds of chemicals prior to a local aerial application flight. The 8,500-hour non-instrument rated commercial pilot reported to local authorities that while in-flight he experienced some problems with the on-board agricultural-navigation system; however, he elected to proceed to the field to be sprayed. While enroute to the field, the PT6A series engine surged a couple of time and lost power. The pilot attempted to execute a forced landing to a pasture. During the approach, the pilot was forced to make a sharp turn to avoid colliding with a fence, resulting in a hard landing and a loss of directional control. The payload of chemicals was found in the hopper, and the reason why the pilot was unable to dump the load following the loss of engine power was not determined. The 2005 model airplane sustained major structural damage in the area aft of the engine firewall. Examination of the airplane by a Federal Aviation Administration inspector, who traveled to the accident site, revealed less of a cup of fuel was found in one tank and less than 5 gallons were found in the other. A completed Pilot/Operator Aircraft Accident/Incident Report (NTSB Form 6120.1) was not received from either the pilot or the operator.