What happened
On May 5, 2018, at approximately 12:50 UTC, a pilot was conducting a training flight in accordance with a flight training program. The flight involved a closed-route navigation task. While flying near Ostrowiec Świętoklyski at an altitude of 2,500 ft, the pilot observed an automatic drop in engine speed from approximately 2,200 RPM to 2,100 RPM. Simultaneously, the charging light illuminated, and the oil temperature decreased to the minimum edge of the green operating range.
Following the engine fluctuations, the pilot decided to terminate the navigation task and diverted the Cessna 152 toward Lublin Airport (EPLB). During the approach to Lublin, the engine parameters stabilized. The pilot then elected to continue the flight to the departure airfield, Depułtycze Królewskie (EPCD), where a safe landing was completed. There were no injuries resulting from this incident.
The investigation
Following the landing, the malfunction was recorded in the aircraft's technical logbook, and the aircraft was handed over to maintenance personnel. The subsequent technical inspection included checking the fuel sediment and the replacement of cylinder number 3. After a successful engine test, the aircraft was returned to service.
Findings
- The primary cause of the engine malfunction was likely excessive clearance on the exhaust valve stem guide in cylinder number 3.