Factual Information
On 16 September 2017, at approximately 14:47 local time, a Moravan/Zlin Z-142 aircraft, registration SP-ASM, departed from Sobienie-Jeziory Airport (EPSJ). The aircraft carried the pilot-owner, who held a Private Pilot License (PPL(A)), and one passenger, a military pilot with high qualifications.
Sequence of Events
Shortly after takeoff, during the initial climb following rotation, the engine began to malfunction, accompanied by a small amount of black smoke. At an altitude of approximately 50–100 m above ground level (AGL), the aircraft entered a left turn. The engine disturbances and black smoke continued. After changing direction by about 90° to the left, the aircraft rapidly lost altitude. Close to the ground, it stalled and subsequently struck the ground in an almost flat attitude, approximately 800 m from the eastern threshold of the runway at EPSJ. The impact occurred on agricultural wasteland. At the moment of impact, the engine was either not running or operating at very low power. Post-accident inspection found that the supercharger was not engaged (the control knob was not pushed in). The pilot reported that he switched off the ignition before impact but did not turn off the electrical system or close the fuel valve. No fire occurred, although the fuel system in the fuselage was ruptured.
Injuries and Damage
Both the pilot and passenger sustained serious injuries. They were evacuated from the cockpit with assistance from personnel arriving from EPSJ and emergency services, then transported to hospitals by helicopter emergency medical services. The aircraft sustained extensive damage from the impact and subsequent dismantling, rendering it beyond repair. The propeller, engine mount, engine bay systems, lower and forward fuselage, landing gear, canopy, oil system, and fuel system were destroyed or damaged.
Probable Causes
The investigation determined three causes of the accident: 1) failure to comply with aircraft maintenance requirements as specified in the engine manufacturer's documentation and the individual maintenance program; 2) engine failure resulting from damage and destruction of the compressor rotor ball bearing due to inadequate lubrication and progressive corrosion; 3) a stall during the final phase of the emergency landing.
Contributing Factors
Contributing factors included sporadic aircraft operation with long periods of non-use, incompatibility of available documents from the engine manufacturer regarding operational requirements, and terrain unsuitable for an emergency landing (uneven surface and ditches).
Investigation
The investigation was conducted by the Polish State Commission for Aircraft Accident Investigation (PKBWL). One safety recommendation was issued to the Civil Aviation Authority.