What happened
On August 20, 2005, at approximately 15:32, an amateur-built MJ-10 Spitfire, registration HB-YIZ, was performing a flight demonstration at the Dittingen airfield. The pilot had planned a series of maneuvers, including high-speed passes and various turns, to showcase the aircraft to the spectators.
During the execution of a left-hand turn, the aircraft entered an uncoordinated state. As the pilot increased the bank angle to approximately 70 degrees, the aircraft experienced a sudden roll and yaw toward the left, transitioning into the early stages of a spin. While the pilot managed to recover the aircraft from this uncontrolled state after about three-quarters of a rotation, there was insufficient altitude remaining to complete the recovery maneuver. Consequently, the aircraft collided with trees on a slope near the airfield, resulting in one fatality and the destruction of the aircraft.
The investigation
The Swiss Transportation Safety Investigation Board (SUST) examined the aircraft's construction, flight testing history, and the pilot's experience. The investigation utilized video footage analysis and eyewitness accounts to reconstruct the flight path.
Technical analysis revealed that the aircraft's center of gravity was positioned outside the permitted rear limit. Specifically, the center of gravity was found at 28.4% of the mean aerodynamic chord, exceeding the designer's specified range of 18% to 28%. Furthermore, investigators identified structural characteristics involving the wing profile and washout that contributed to an abrupt stall at high angles of attack. The investigation also noted that the flight testing program for this amateur-built aircraft was incomplete, as it had not met the recommended 35 flight hours required by the Swiss amateur-built aircraft handbook.
Findings
- The primary cause was the loss of control during an insufficiently coordinated left turn.
- Design flaws in the aircraft led to demanding handling characteristics during high angles of attack.
- The center of gravity was located beyond the aft limit.
- The flight testing of the amateur-built aircraft was insufficient.
- There were deficiencies in the oversight of the construction and certification processes.
- The pilot lacked sufficient experience operating this specific type of demanding amateur-built aircraft.