What happened
On July 7, 2013, a student pilot was conducting a solo navigation flight from EPRZ to EPKR. While flying near Pruchnik, the Cessna 152 experienced a sudden and violent loss of engine power. This power loss occurred without any prior warning or symptoms. The engine continued to run only at minimum RPM and failed to respond to any adjustments of the throttle.
In response to the engine failure, the pilot performed an emergency landing in a plowed field. During the aircraft's landing roll, the nose gear strut detached from the airframe, which subsequently caused the aircraft to capsize. There was no fire following the impact, and the pilot was able to exit the cockpit uninjured.
The investigation
The PKBWL examined the engine following the accident to determine the cause of the power loss. The inspection revealed several mechanical irregularities within the engine components. Specifically, investigators found a lack of compression in cylinder number 1 due to a stuck intake valve, and reduced compression in cylinder number 4 caused by an improperly seated exhaust valve. Additionally, significant carbon buildup was noted on the spark plugs in cylinders 2 and 4. The investigation also identified that the ignition timing angles on both magnetos were set too high, measured at 28° and 27°, compared to the required 20°.
Findings
- Loss of compression in cylinder 1 caused by a stuck intake valve.
- Reduced compression in cylinder 4 caused by an unseated exhaust valve.
- Excessive ignition advance on both magnetos.
- Heavy carbon deposits on spark plugs in cylinders 2 and 4.