CEN17LA295

The airline transport pilot flew his experimental, amateur-built biplane on a cross-country flight with multiple legs and refueling stops. About 1 hour, 15 minutes into the flight and 15 miles from his destination, the pilot initiated a descent from 3,500 ft to 2,500 ft. When the pilot added power to level off, the engine began to run rough and experienced a partial loss of power. The pilot said that he immediately applied carburetor heat but observed no improvement in engine operation. The engine continued to lose power and "sputter." During the subsequent forced landing, the airplane touched down on unsuitable terrain at the edge of a soybean field, decelerated rapidly, and nosed over. A postaccident examination of the wreckage revealed no preimpact anomalies that would have precluded normal operation of the engine. Nearby weather was conducive to serious icing at descent power about the time of the engine power loss. Although the pilot reported that he applied carburetor heat, it is likely that, at the time of application, the ice had already accumulated in the carburetor to the extent that the carburetor heat was insufficient to melt the ice and restore full engine power.

On July 30, 2017, about 1700 eastern daylight time, an experimental amateur-built Steele Acro Sport II biplane, N896JC, nosed over during a forced landing following a partial loss of engine power near Loudonville, Ohio. The airline transport pilot reported he was uninjured and his passenger received minor injuries. The airplane sustained substantial wing damage during the nose over. The airplane was registered to and operated by the pilot as a 14 Code of Federal Regulations Part 91 personal flight. Day visual meteorological conditions prevailed in the area of the accident site about the time of the accident, and the flight was not operated on a flight plan. The flight originated from the Smith Field Airport (SMD), near Fort Wayne, Indiana, and was destined for the Holmes County Airport (10G), near Millersburg, Ohio. The pilot's accident report indicated the purpose of the flight was to return to Brunswick, Maine, from Oshkosh, Wisconsin after it had been recently restored. The return flight was conducted through multiple legs and refueling stops, the last one being SMD. According to operations personnel at SMD, the airplane had landed at SMD and was serviced with 15.8 gallons of 100 low lead, self-serve fuel at 1543. The airplane departed SMD with a total of 18 gallons of fuel. About 15 miles from the 10G and 1:15 hours into the flight, the pilot initiated a descent from 3,500 ft to 2,500 ft. When the pilot added power to level off, the engine began to run rough. The pilot said that he immediately applied carburetor heat and he observed no engine operation improvement. The engine continued to lose power and "sputter." The pilot selected a field for a forced landing. However, during the descent, the "undulating" features of the field were noticed. The pilot elected to land the airplane upslope, it rolled a short distance, regained flight at the crest of a hill, and touched down at the edge of a soy bean field. The airplane decelerated rapidly and nosed over. Inspectors from the Federal Aviation Administration conducted a postaccident examination of the wreckage. Examination of the engine and fuel system revealed no preimpact anomalies that would have precluded operation of the engine. At 1852, the recorded weather about 19 miles and 306° degrees from the accident site at the Mansfield Lahm Regional Airport (MFD), near Mansfield, Ohio, was: Wind 340° at 8 kts; visibility 10 statute miles; sky condition clear; temperature 26° C; dew point 14° C; altimeter 30.17 inches of mercury. At 1752, the recorded weather at MFD was: Wind 360° at 9 kts; visibility 10 statute miles; sky condition clear; temperature 27° C; dew point 13° C; altimeter 30.17 inches of mercury. At 1652, the recorded weather at MFD was: Wind 340° at 11 kts; visibility 10 statute miles; sky condition clear; temperature 28° C; dew point 15° C; altimeter 30.17 inches of mercury. The recorded MFD temperature and dew point data were plotted on a carburetor icing chart. The charted datashowed that the weather was conducive to serious icing at descent power near the time of the engine power loss. The Pilot's Handbook of Aeronautical Knowledge, in part, stated: When conditions are conducive to carburetor icing during flight, periodic checks should be made to detect its presence. If detected, full carburetor heat should be applied immediately, and it should be left in the ON position until you are certain that all the ice has been removed. If ice is present, applying partial heat or leaving heat on for an insufficient time might aggravate the situation. In extreme cases of carburetor icing, even after the ice has been removed, full carburetor heat should be used to prevent further ice formation. A carburetor temperature gauge, if installed, is very useful in determining when to use carburetor heat.