ERA13LA138

The pilot reported that the airplane was topped off with 60 gallons of fuel prior to departure and that he applied a spray application to a field for about 30 minutes before returning to the airplane's home base. While enroute, the engine lost power and the pilot was unable to restart the engine. He then performed a forced landing in a field, during which both wings sustained substantial damage. After the accident, about 35 gallons of fuel remained in the left wing and 5 gallons remained in the right wing. Postaccident examination indicated that the left forward wing fuel line was partially blocked; the aft left and both right wing fuel lines were free of obstruction. Additionally, the fuel control unit was contaminated with debris. All other fuel system parts were free of obstructions. The left forward fuel line and fuel fitting were sent to the NTSB materials laboratory for examination and were found to be blocked with debris consistent with soil. The debris in the left forward wing fuel line alone would not have reduced fuel flow to the engine; however, the contamination of the fuel control unit likely would have reduced fuel flow sufficient to cause fuel starvation. The investigation was unable to determine the origin of the debris.

On February 15, 2013, about 1500 eastern standard time, a Ayres Corporation S2R-T34, N3095X, was substantially damaged during a forced landing near Fort Gaines, Georgia. The commercial pilot was not injured. The airplane was registered to, and operated by, Coates Flying Service Incorporated, under the provisions of 14 Code of Federal Regulations Part 137, as an aerial application flight. Visual meteorological conditions prevailed and no flight plan was filed. The flight departed from Coates Airport (79GA), Fort Gaines, Georgia at 1430. According to the pilot, prior to departure the airplane was fueled with a total of 60 gallons of fuel and the fuel tanks were full. He further reported that he was applying a spray application to a field for approximately 30 minutes before returning to the airplane's home base. While enroute, the engine lost total power and "flamed out." The pilot was unable to restart the engine and performed a forced landing in a field, during which both wings were substantially damaged. An examination of the airplane by a Federal Aviation Administration inspector revealed that approximately 35 gallons of fuel remained in the left wing, while the right wing had evidence of only having 5 gallons remaining. The inboard tank access panels were removed and no visible contamination was noted in the fuel tanks or the fuel line fittings. No blockage was noted at the forward and aft of the fuel tank lines. The four wing fuel lines, two lines on each tank, were examined, by applying shop air to each individual line. The results revealed that the left forward line had a partial blockage, but the aft left and both right wing fuel lines were free of obstruction. The wing tank fuel vents were also checked and no discrepancies noted. The fuel system filters were examined for contamination and the main fuel filter, header tank fuel filter and the fuel located within the filter housings were clean with no contamination. The fuel filters on the high pressure fuel pump were checked and also had no evidence of contamination. A review of the Aircraft Maintenance Manual revealed that the fuel system consists of integral wing tanks in each wing and are interconnected through a 5 gallon header tank located in the fuselage. The fuel system is equipped with two fuel filters, a mesh finger strainer at the outlet fitting from the header tank, and a main fuel filter, which was located on the forward side of the firewall. The fuel supply lines to the engine are routed from the header tanks outlet finger screen through a fuel shutoff valve to an electric driven fuel boost pump. The electric driven fuel boost pump discharges through the main fuel filter to an engine driven fuel pump. An examination of the engine by a Pratt & Whitney investigator revealed that the propeller could not be rotated due to impact damage. The propeller was removed to access the components within the engine. The engine was disassembled at the turbine section and all components movedfreely from the reduction gear box section, turbine section, and compressor section with no anomalies noted. The high pressure fuel pump, starter control unit, and oil to fuel heater were sent to Pratt & Whitney, Canada for further examination. Under supervision of the Transportation Safety Board of Canada, the result of the findings revealed that the fuel control unit was contaminated with debris. The high pressure fuel pump was noted to be in serviceable condition but the fuel performance was low. The starter control unit was found serviceable and the fuel heater thermal element was found unserviceable. The left wing forward fuel line and fuel fitting was sent to the NTSB Materials Laboratory for examination and revealed that blockage was found within the fuel line fitting. The debris found within the fuel line was consistent with soil.