What happened
On July 5, 2009, a Cessna TU206E, registration OK-RFC, was conducting a parachute jump operation near Tábor Airport (LKTA). After dropping the jumpers from FL110, the pilot began a descent. Following instructions from the airfield information service to avoid glider activity, the pilot chose to descend north of the airfield.
During the descent, the pilot noted low engine temperatures and adjusted the manifold pressure and mixture settings. However, while on the third circuit of runway 30, the pilot realized the engine power was not responding to throttle inputs, despite the propeller continuing to rotate. The engine performance was fluctuating, and the pilot was unable to regain sufficient power to reach the runway.
Unable to reach the aerodrome, the pilot executed an emergency landing in a field covered with tall crops (approximately 0.7–1.0 m high) near the edge of a forest. During the landing, the aircraft struck the ground, causing the nose gear to collapse and the aircraft to capsize onto its back. The pilot was uninjured.
The investigation
The ÚZPLN investigation focused on the engine's performance and the pilot's management of the descent. Post-accident inspections of the Continental TSIO 520C3B engine, including compression tests and a lubricated oil analysis, revealed no mechanical defects, maintenance errors, or internal damage that could have caused the power loss. The fuel system and electrical fuel pump were also found to be fully operational.
The investigation also reviewed the pilot's experience. While the pilot held a valid CPL(A) and had recently completed difference training on the Cessna TU206E, the investigation noted a lack of practical experience regarding the specific engine management required during prolonged descents from high altitudes.
Findings
- The primary cause of the accident was the pilot's insufficient practical experience in maintaining engine operation during a rapid descent from high altitude.
- The pilot identified the engine power deficiency too late, at a distance from the airport that made a return to the runway impossible.
- The choice of the landing site was the only viable option available given the circumstances.
- The impact with the tall crops and the steep angle of descent during the maneuver led to the failure of the nose gear and the subsequent capsizing of the aircraft.