What happened
On August 20, 2017, at approximately 20:30 UTC, a Starflight Fox V-4 ultralight aircraft, registration PU-GAT, departed from Aeródromo do Sítio Flyer in Palmas, Tocantins, for a scenic flight. The aircraft was carrying a pilot and one passenger.
During the flight, the aircraft entered a steep turn of approximately 270 degrees at an altitude of roughly 60 meters. During this maneuver, the aircraft experienced a loss of lift on the right wing, leading to an aerodynamic stall. The aircraft subsequently impacted the ground and was destroyed by a post-crash fire. The passenger sustained fatal injuries, while the pilot suffered serious injuries.
The investigation
The CENIPA investigation focused on the aerodynamic conditions and the pilot's actions during the maneuver. Investigators examined flight footage which showed the aircraft maintaining a stable bank and altitude for a significant period before the stall, contradicting the pilot's claim of a control failure. While a broken wing tie-rod was found, it could not be determined if this occurred before or after the impact.
Analysis of the aircraft's manual revealed that performing high-bank turns at altitudes below 90 meters is prohibited. Furthermore, the manual specifies that during an accidental stall, the pilot should use the rudder to level the wings and avoid using ailerons. The investigation noted that the aircraft was an amateur experimental model without a certificate of airworthiness, and maintenance records were not up to date.
Findings
- The primary cause of the accident was an aerodynamic stall induced by a prolonged, high-bank turn that increased the stall speed beyond the aircraft's actual velocity.
- The pilot's failure to follow established recovery procedures—specifically the potential use of ailerons instead of rudder to level the wings—contributed to the loss of control.
- The pilot was operating without the required technical ratings (UATE and ULTK) for this specific type of flight.
- The aircraft was an experimental amateur build lacking a certificate of airworthiness and updated maintenance logs.
- The pilot's decision-making and flight discipline were identified as contributing factors to the occurrence.