What happened
On June 16, 2015, a Socata TB9 engaged in a routine tourist flight departing from Poznań-Ławica Airport (EPPO). Prior to departure, the pilot performed a standard engine test, which revealed no operational anomalies. However, during the initial climb phase following takeoff, the engine failed to reach maximum RPM and began operating unevenly.
Upon detecting the engine instability, the pilot contacted the EPPO tower to report the malfunction and requested permission to return to the airport. The request was granted, and the pilot executed a left holding pattern over the airfield. After approximately seven minutes of flight, the aircraft landed safely on runway 28 without further incident.
The investigation
The investigation, conducted by the operator's internal commission, focused on the mechanical performance of the powerplant during the climb. The inquiry examined the engine's behavior during the takeoff roll and the subsequent period of instability during the ascent.
Findings
The investigation established that the engine's inability to maintain steady, high-power output was caused by incorrect valve clearance.