What happened
On August 6, 2009, a Cessna 150L, registration OK-AVI, was performing a navigational flight from Roudnice nad Labem toward Bezděz Castle with one passenger on board. The flight proceeded normally until approximately 09:44 UTC, when the pilot heard an unusual noise from the engine and experienced a loss of power while flying at 250 m AGL. Despite attempts to adjust the throttle, the engine power continued to decrease, making level flight impossible.
The pilot identified a nearby field for an emergency landing. During the approach, the aircraft touched down on the left main gear, followed by the right gear, and then the nose gear. Upon impact with an uneven patch of terrain, the nose gear collapsed, causing the aircraft to flip over the propeller and land upside down. The engine remained running until the propeller struck the ground. There were no injuries to the pilot or the passenger, though the aircraft sustained extensive damage.
The investigation
The ÚZPLN investigation examined the engine, the aircraft's maintenance history, and the meteorological conditions at the time of the accident. Investigators performed a teardown of the Continental O-200-A engine. While they found a broken tooth on the drive gear of the crankshaft, they determined this was not the cause of the power loss during flight. The investigation also reviewed the pilot's recent flying experience and the weather data from the Doksany station.
Findings
- The primary cause of the accident was an uncontrolled emergency landing, as the pilot failed to manage the landing speed and approach with flaps retracted.
- The engine power loss was likely caused by carburetor icing, as the ambient temperature, dew point, and humidity levels were within the range highly conducive to ice formation in the induction system.
- The pilot was flying in violation of JAR-FCL 1.026 regulations, as they had not performed the required three take-offs and landings in the same aircraft type within the preceding 90 days before carrying a passenger.
- The aircraft sustained significant structural damage, including a broken keel, deformed wings, and a collapsed nose gear, resulting from the impact and subsequent inversion.