What happened
On August 27, 2016, a Cessna 152 was conducting a VFR training flight from EPLR to EPML. After completing refueling and a pre-flight inspection, the pilot departed the airfield with a planned cruise altitude of 2,800 ft AMSL. The flight was operating under VMC conditions.
Approximately 20 minutes into the flight, while operating near the town of Kraśnok, the pilot experienced a significant loss of engine power accompanied by heavy vibrations from the powerplant. Simultaneously, the oil temperature rose abruptly beyond the maximum allowable limits. The pilot notified FIS Warszawa of the engine difficulties and subsequently executed an emergency landing in an improvised field. The landing was completed without damage to the airframe, and the pilot remained uninjured.
The investigation
The investigation focused on the mechanical failure of the engine components following the sudden loss of power and temperature increase. The investigation established the sequence of mechanical failures within the engine's internal structure.
Findings
- The primary cause of the engine failure was the loosening of the nut securing the connecting rod cap.
- This loosening led to the failure of a second bolt, which subsequently caused the connecting rod to detach from the engine crankshaft at the third cylinder crankpin.
- The resulting mechanical failure caused the crankshaft, connecting rod, and cylinder assembly to become jammed.