On May 20, 2006, about 1830 central daylight time, a single-engine Boeing A75 tailwheel-equipped biplane, N58072, was substantially damaged during a hard landing following a partial loss of engine power shortly after takeoff from the Jennings Airport (3R7), near Jennings, Louisiana. The commercial pilot and the sole passenger were not injured. The vintage airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The local flight was originating at the time of the accident. The 4,900-houor commercial pilot reported that shortly after takeoff from Runway 17, (a 2,000-foot-long by 150-foot-wide grass runway), the 220-horsepower radial engine sustained a partial loss of power. The pilot was unable to maintain altitude and elected to land to an open field. As the pilot was attempting to avoid a "tall" fence, the airplane experienced a hard landing. There was no postimpact fire and the pilot and passenger were able to egress the airplane unassisted. The pilot further reported that as a result of the hard landing the fuselage was twisted and the lower left wing's main spar was broken. A representative from the NTSB examined the airplane at Air Salvage of Dallas, near Lancaster, Texas. An examination of the airplane's gravity fed fuel system revealed that the single 46-gallon fuel tank contained approximately 12 gallons of a blue liquid consistent with 100 Low Lead aviation fuel. The engine primer was found in the "in and locked" position. The fuel tank vent was found unobstructed. The fuel selector valve was tested and found to be operational. Both of the wooden propeller blades were splintered and destroyed from midspan outward. The front spark plugs were removed and no anomalies were noted. Thumb compression was obtained in each cylinder by rotating the engine via its propeller. Valve train continuity was established to all valves and to the accessory gears. Both engine magnetos' produced spark when rotated by hand. The engine oil screen was removed and no visible metal particles or obstructions were observed. The fuel gascolator screen was found clean and unobstructed. The engine carburetor was removed and disassembled. The carburetor float did not contain liquid and no anomalies were noted with the needle and seat. No anomalies were found with either the airframe or the engine that could have prevented normal flight. A review of the carburetor icing chart by the Investigator In Charge (IIC) revealed that, at the time of the accident, conditions were not conducive for carburetor icing at takeoff power. The reason for the reported loss of engine power could not be determined. At 1755, the weather observation facility at Chennault International Airport (CWF), near Lake Charles, Louisiana, located 25 nautical miles west from the site of the accident, was reporting the wind from 220 degrees at 13 knots, visibility 10 statute miles, clear of clouds, temperature 80 degrees Fahrenheit, dew point 57 degrees Fahrenheit, humidity 45 percent, and a barometric pressure setting of 29.96 inches of Mercury.