What happened
On July 3, 2015, a Zenair Zodiac CH 601 was engaged in a recreational flight between Piotrków Trybunalski (EPPT) and Pajęczno. During the flight, the pilot experienced increasing engine vibrations. In response to the vibration, the pilot performed a precautionary landing in a field approximately 500 meters long.
Upon inspection, the pilot discovered that two screws securing the propeller spinner had unscrewed and fallen out, which had been the source of the vibrations. After replacing the screws and verifying the field conditions, the pilot performed a solo test flight to confirm the aircraft was airworthy. Following this, the pilot returned to the field to pick up a passenger for a second departure attempt.
During the second takeoff roll, after traveling approximately 20 to 25 meters, the right wingtip struck a compressed straw bale. This impact caused the aircraft to rotate and lose directional control, leading the propeller to strike a second straw bale, which ultimately brought the aircraft to a halt. There were no injuries to the crew, no fire, and no fuel leaks occurred.
The investigation
The investigation, conducted by a user commission, examined the sequence of events involving two distinct phases: an initial incident involving engine vibrations and the subsequent accident during takeoff. The investigators analyzed the mechanical state of the aircraft, specifically the missing propeller spinner screws, and evaluated the pilot's actions during the takeoff roll in the field.