What happened
On April 9, 2018, an ultralight aircraft, registration OK-OUF 88, crashed in a field near the village of Kundratice, Czech Republic. The flight was part of a training session intended to prepare a student pilot for a practical proficiency check. The crew, consisting of a student pilot in the left seat and an instructor in the right seat, had been performing a series of simulated emergency and safety landings.
Following the completion of these maneuvers, the aircraft began a climb. During the transition to repeat a circuit, the pilot increased engine power. This sudden increase in power generated a significant torque effect. Due to insufficient control compensation, the aircraft tilted to the left and entered a descending spiral. Witnesses on the ground observed the aircraft performing erratic maneuvers at a very low altitude before it struck the ground. The impact was followed by a post-crash fire and explosion that destroyed the D4BK F80/100 Fascination.
The investigation
The ÚZPLN investigation examined the flight trajectory, aircraft maintenance records, and the qualifications of the crew. Investigators utilized flight tracking data from Live Track 24 and several eyewitness accounts to reconstruct the final moments of the flight. The investigation also reviewed the training syllabus and the aircraft's weight and balance parameters.
Investigators found that the aircraft was significantly overloaded. The actual takeoff weight was approximately 573 kg, exceeding the maximum takeoff mass (MTOM) by about 100.5 kg. This weight excess was primarily due to the combined weight of the crew and the fuel load. Furthermore, the investigation noted that the aircraft type used was not officially designated for primary flight training under local regulations, and the instructor's ability to intervene was physically limited by the aircraft's single-lever control design.
Findings
- The primary cause of the accident was a gross pilot error during the initial climb phase while repeating a circuit, which led to an unrecoverable descent.
- The aircraft was operating significantly above its maximum takeoff mass, which negatively impacted its handling characteristics and increased the stall speed.
- The student pilot had begun practical flight training before completing the required theoretical training.
- The training syllabus prescribed by the LAA ČR was not strictly followed by the instructor.
- The aircraft type was unsuitable for the level of basic training being conducted due to its performance characteristics and cockpit configuration.