Accident Overview
On a private flight from Rottweil-Zepfenhan Airport to Lugano, a single-engine airplane departed at 1056 local time. The aircraft carried one pilot and one passenger. While climbing at flight level 070 in instrument meteorological conditions (IMC), the fuel filter bypass warning light on the cockpit panel illuminated briefly before extinguishing. Approximately one minute later, the engine lost power.
Sequence of Events
The aircraft began to descend. The pilot attempted to restart the engine twice. He initially intended to return to Rottweil Airport but determined that neither Rottweil nor Donaueschingen-Villingen Airport could be reached from the current altitude. He considered Schwenningen Airport too hazardous due to surrounding forest, buildings, and a short runway. He elected to perform an emergency landing in an open field. The airplane touched down with the landing gear extended in a field near Dauchingen, approximately 15 kilometers southwest of Rottweil Airport. After touchdown, the aircraft struck irregularities on the ground, causing the undercarriage to be torn off. The airplane came to rest on a path with both wings partially sheared off. Both occupants exited the airplane with minor injuries.
Investigation Findings
Inspection of the fuel system revealed that the fuel filter was heavily clogged with a brown-black substance. When an attempt was made to drain the filter before removal, no liquid flowed out. The sump tank contained heavy contamination, and only a small amount of fuel was found at its bottom.