What happened
On May 6, 2019, a Cessna 152, registration SP-MAA, was conducting a flight training mission at Warsaw-Modlin Airport (EPMO). During the approach to landing, the pilot noticed the engine was operating irregularly, with RPM fluctuating between 1000 and 2000. In an attempt to stabilize the engine, the pilot increased power to 2300 RPM and engaged the carburetor heat, which temporarily restored smooth operation.
Upon entering the landing straight for runway 08, the pilot declared a MAYDAY via radio. This prompted the airport operational duty officer to declare a "FULL EMERGENCY" (PEŁNE ZAGROŻENIE) for airport services. Despite the emergency declaration, the aircraft landed safely without further engine issues. No injuries were reported, and the aircraft sustained no damage.
The investigation
The PKBWL investigation focused on two primary areas: the mechanical cause of the engine instability and the effectiveness of the airport's emergency response.
Regarding the aircraft, a post-flight inspection by a mechanic revealed that the fuel primer lever had not been secured. This allowed excess fuel to be drawn into the engine, causing the observed RPM fluctuations.
Regarding the airport response, the investigation examined the communication between the Tower controller and the airport operational duty officer. The investigation also reviewed the actions of the Airport Rescue and Firefighting Service (LSRG) following the emergency declaration.