What happened
On October 5, 2019, a Cessna 152 was conducting a student pilot training flight (PPL(A) syllabus) at the Świdnik (EPSL) airfield. During the ninth flight of the day, while climbing at an altitude of approximately 100 meters, the instructor pilot noticed that the engine was running unevenly.
Due to the proximity of the Lublin (EPLB) runway 07 along the flight path, the instructor decided to perform a precautionary landing at the larger airport. The pilot notified the Lublin Tower controller of the intention to land. The landing was completed without incident. Following the landing roll, the instructor requested taxi instructions to the main apron, where the engine was shut down with the assistance of the airport fire service. Although emergency services were present, the instructor informed them that assistance was not required. After consulting with a mechanic via telephone, the instructor decided to taxi the aircraft to the Aeroklub Świdnicki hangar.
The investigation
The investigation focused on the engine's performance and the maintenance history of the aircraft. On October 7, 2019, a qualified mechanic performed an inspection of the engine. The investigation established that a 50-hour inspection had been performed on the engine just hours before the incident, during which all spark plugs were tested on a test bench and found to be functioning correctly.
Findings
- The engine malfunction was caused by a crack in the porcelain insulation of one of the spark plugs.
- The crack in the insulator was not present during the 50-hour inspection conducted shortly before the flight.