ERA11LA173

The pilot reported that about 3 hours into his cross-country flight the engine began to surge and lose power. He initially thought it was carburetor ice and turned on the carburetor heat. The carburetor heat seemed to improve engine performance briefly, but the engine began to surge again and eventually stopped running. The pilot made an emergency forced landing in a field with the landing gear up and flaps down, incurring substantial damage to the underside of the airplane. A postaccident examination of the fuel system revealed no blockage or contamination of the fuel. According to the Federal Aviation Administration’s carburetor icing probability chart, the temperature/dew point combination at the time of the accident met the conditions favoring formation of serious carburetor icing at cruise power. It is likely that the loss of engine power resulted from carburetor icing.

On February 14, 2011, at 1427 eastern standard time, a Globe Swift GC-1B, N80741, lost total engine power while in cruise flight over Anderson, South Carolina. The pilot made a forced landing in a field and the airplane was substantially damaged. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulation Part 91 as a personal flight. Visual meteorological conditions prevailed and no flight plan was filed. The certificated airline transport pilot was not injured. The flight originated from Wilmington International Airport, Wilmington, North Carolina at 1133. The pilot reported that prior to departure; he conducted a preflight and visually verified that the fuel tanks were full with 35 gallons of usable fuel. He sampled fuel from both the fuel strainer and fuel sump and found no contamination. According to the pilot, the engine burned approximately 8 gallons of fuel per hour, and approximately three hours into his cross-country flight, at an altitude of 4,500 feet, 12 miles southeast of his destination, the engine began surging and losing power. He initially thought it was carburetor ice and turned on the carburetor heat. The carburetor heat seemed to improve engine performance briefly, but then the engine began to surge and eventually it stopped running. The pilot made an emergency forced landing in a field with the gear up and flaps down, incurring substantial damage to the underside of the airplane. The examination of the wreckage was conducted by a Federal Aviation Administration (FAA) inspector under the direction of the NTSB. On arrival at the scene, the FAA inspector detected the odor of fuel. Further examination of the wreckage revealed that the underside of the nose and cowling were crushed. Flight control continuity was established to all the flight control surfaces. A visual inspection of the fuel vent line revealed that the line was unobstructed. The fuel cap was checked for security and it was found sealed and locked. The wreckage was recovered for further examination by the NTSB. Examination of the airplane by the NTSB revealed that the carburetor and the associated fuel lines were broken and separated from the engine. The carburetor was not located or recovered from the accident site. An examination of the engine revealed that due to the external damage, an engine run could not be performed. During a cursory engine examination the crankshaft was rotated by hand and valve train continuity and cylinder compression was confirmed. Further examination revealed that spark was obtained on all ignition leads. The top and bottom spark plugs were examined and exhibited normal wear signatures when compared to the Champion spark plug chart. It was noted that the airplane was equipped with two 13 gallon wing tanks and a nine gallon center fuel tank. A residual amount fuel was observed in the center tank. There was a residual amount of fuel found in the fuel lines and in the fuelmanifold. A check of the fuel system revealed no blockage or contamination of the fuel. Approximately one gallon of fuel was added to the center fuel tank and the electric fuel pump was checked for operation. The fuel pump operated and depleted all of the fuel out of the center tank. The ambient temperature at the time of the accident was 48°F and the dew point was 36°F. According to the Federal Aviation Administration carburetor icing probability chart, this temperature/dew point combination meets the conditions favoring formation of serious carburetor icing at cruise power.