What happened
On October 30, 2014, a Piper Arrow PA-28R was conducting a training flight at Warsaw-Modlin Airport (EPMO). The flight, which was part of a new type rating training program, was being conducted by a flight instructor and a student pilot. The flight plan included performing circuit patterns and a flight to a designated zone.
During the initial climb following takeoff, the instructor noticed abnormal engine behavior. The engine exhibited irregular operation characterized by sudden drops in RPM, fluctuating between 50 and 100 RPM for durations of approximately 2 to 3 seconds. Due to this instability, the crew decided to land as soon as possible. The instructor contacted the air traffic controller to request priority landing, citing the engine issues. The controller granted priority and offered emergency assistance, which the crew declined, as the primary goal was to inspect the engine's technical condition.
The aircraft landed normally and taxied to the hangar. Following the incident, two PART-145 licensed mechanics inspected the aircraft and the engine. Ground tests were subsequently performed, and no further irregularities were detected.
The investigation
The investigation was conducted by the operator's internal investigation team. The inquiry focused on the cause of the engine's erratic RPM behavior during the climb phase and the subsequent mechanical inspections performed on the ground.