What happened
On August 22, 2020, a Jak-12M aircraft, registration SP-KRC, was conducting parachute jump operations at EPRJ airport. Following a successful engine run-up that showed normal operating parameters, the pilot departed from runway 26R with three skydivers on board.
Shortly after takeoff, as the pilot reduced engine RPM to nominal levels, the engine began operating unevenly and failed to maintain the required revolutions. Recognizing the instability, the pilot declared an emergency to the controller at the adjacent EPRZ controlled airspace and requested an immediate landing on the parallel runway 27R. The aircraft landed safely without further incident.
The investigation
Following the event, the aircraft underwent a technical inspection on the ground. A subsequent engine run-up performed on the ground did not replicate the malfunction. The investigation focused on the fuel delivery system to identify why the engine failed to maintain power during the climb.
Findings
- The investigation established that a fuel filter near the fuel pump had become loose.
- This loosening caused a partial blockage in the fuel installation, leading to the engine's uneven performance and inability to maintain RPM during flight.