What happened
On July 22, 2020, an amateur-built FC-04 Pegasus ultralight, registration PU-FCC, was performing its first flight following completion of construction. The aircraft departed from the São João Del Rei Aerodrome (SNJR) in Minas Gerais, Brazil, under favorable meteorological conditions.
Shortly after takeoff, while the pilot was executing a left turn, the aircraft began experiencing intense vibrations. This instability led to a total loss of control, forcing the pilot to perform an emergency landing. The aircraft subsequently collided with the roof of a hangar. The impact resulted in substantial damage to the aircraft and caused serious injuries to the pilot.
The investigation
CENIPA investigators examined the wreckage and flight data to determine the cause of the loss of control. The investigation focused on the structural integrity of the tail section and the mechanical state of the control surfaces.
Investigators recovered the trim actuator approximately 200 meters away from the main wreckage, confirming it had detached during flight. The investigation also reviewed cockpit video footage recorded by the pilot, which captured the moment the control column began vibrating violently and showed the tail section oscillating significantly. While the trailing edge rod was found near the wreckage, investigators determined it likely broke upon impact with the hangar roof rather than during the flight itself.
Because the aircraft was an amateur-built experimental model, the components and materials did not hold standard aeronautical certification, and no formal laboratory testing was performed on the collapsed parts.
Findings
- The primary cause of the accident was a structural failure of the right elevator.
- The failure was triggered by the detachment of the elevator actuator during flight, which left the control surface loose.
- The resulting uncontrolled oscillations of the elevator created resonant forces in the empennage, transmitting severe vibrations through the control column and rendering the aircraft uncontrollable.
- Contributing factors included undetermined manufacturing or material handling issues.