Accident Details
A ferry flight experienced an engine power loss, necessitating a forced landing in a soft field. Upon landing, the airplane nosed over. The pilot and an accompanying mechanic were on board. The accident occurred approximately one hour after a precautionary landing earlier in the flight.
Investigation Findings
A post-crash investigation discovered that the carburetor fuel-inlet filter screen was mostly blocked with a lint-like material. Microscopic examination determined the material appeared to be cloth fibers. The source of the material was not determined.
Background
The engine had experienced repeated, intermittent power losses over the previous week. Company mechanics made repeated efforts to locate the source of the problem. During those efforts, contamination was found in the fuel system; filters were cleaned and the fuel system was flushed. However, the intermittent power losses recurred. On the day of the accident, the engine began to surge, and a precautionary landing was made. The mechanic accompanying the pilot reportedly found no problems, and the flight was continued.