What happened
On June 7, 2020, at 15:48 LMT, a KR-030 Topaz, registration SP-STRT, was performing a flight from EPGO (Góraszka) to EPRP (Radom – Piastów) when the aircraft experienced a significant drop in engine power accompanied by vibrations. The pilot attempted to mitigate the issue by activating the electric fuel pump and adjusting the throttle setting; however, the power remained insufficient to maintain level flight.
After notifying FIS Warszawa of the situation and the intention to land, the pilot executed a precautionary landing in a field with low-growing crops near Ksawerów Nowy, Białobrzegi. Due to the uneven terrain of the field, the nose gear fork bent during the final phase of the landing roll, and the propeller blades sustained damage. The pilot sustained no injuries.
The investigation
Following the incident, the aircraft was transported to the manufacturer for inspection. The engine was subsequently removed and sent to a specialized facility in Świdnik for detailed analysis. The investigation focused on the engine's internal components to determine the source of the power loss and vibrations.
Findings
Technical examination of the engine revealed that the main nozzle of the right carburetor, which supplies cylinders number 1 and 3, had unscrewed. This mechanical failure altered the fuel-to-air ratio, creating a mixture that was outside the combustible range for those specific cylinders. Consequently, only cylinders 2 and 4 on the left side of the engine remained operational, resulting in the observed engine power loss and transverse vibrations.