What happened
On September 10, 2013, a TL200 and0 Sting Carbon RG was performing a flight from Goledzinów to Tworzyjanów. While operating near the boundary of the EPWR CTR (between points Mike and Bravo), the aircraft experienced significant vibrations within the powerplant assembly.
In response to the instability, the pilot executed a precautionary landing at the Szymanów aerodrome. Following the landing, a mechanical inspection was conducted to identify the source of the vibration. The inspection revealed that the pitch angle of the variable-pitch propeller blades was inconsistent.
The investigation
The investigation focused on the mechanical integrity of the propeller assembly. Upon examination of the propeller components, investigators identified a failure in the mechanism responsible for blade pitch adjustment. Specifically, the inspection compared a damaged component with an intact one to determine the nature of the malfunction.
Findings
The investigation established that the primary cause of the engine vibrations was a broken screw responsible for rotating one of the propeller blades. This failure resulted in the uneven pitch angle between the blades, leading to the observed instability during flight.