What happened
On 1 March 2024, a pilot performing a sightseeing flight in a Cessna 150F, registration D-EKIQ, experienced a gradual reduction in engine speed while flying near Warsaw. During the flight, the pilot noted that the engine speed dropped to 2,200–2,300 rpm after applying carburetor heat. Believing the issue was a malfunction of the throttle control mechanism rather than icing, the pilot ceased using the carburetor heat.
As the flight continued toward the Babice aerodrome, the engine speed continued to decline. The pilot subsequently decided to perform an emergency landing, selecting an undeveloped, waterlogged area in the Wawer district. Upon touchdown, the aircraft traveled approximately 15 meters before overturning due to the high resistance of the saturated, reed-covered ground. The pilot and passenger sustained no serious injuries, though the passenger received treatment for minor injuries.
The investigation
The PKBWL examined the aircraft's engine, specifically the Continental O-200A, including the spark plugs, oil system, magnetos, and carburetor. An expert examination confirmed that the engine and its control systems were in proper working order at the time of the occurrence. The investigation also analyzed meteorological data, noting high humidity and temperatures conducive to icing. Flight records and pilot statements were reviewed to assess the decision-making process regarding the engine speed fluctuations and the use of carburetor heat.
Findings
- The primary cause of the engine power loss was carburetor icing.
- The pilot misidentified the cause of the engine speed drop, incorrectly ruling out icing and instead suspecting a throttle malfunction.
- The pilot failed to follow the procedures outlined in the Flight Manual, specifically regarding the full application of carburetor heat to clear ice.
- Meteorological conditions, characterized by high humidity and specific temperature ranges, were highly conducive to icing during all phases of flight.
- The pilot made a premature decision to perform an emergency landing when the engine performance was still sufficient to reach the aerodrome.
- The aircraft sustained minor damage to the nose section solely due to the impact with the waterlogged terrain during the overturn.