What happened
On February 19, 2022, at approximately 22:30 UTC, a Hughes 500C (369HS) helicopter, registration LV-LTF, was engaged in a local pleasure flight near Aeródromo Mercedes in the province of San Luis, Argentina. After performing a practice landing on an unpaved surface near a roadway, the pilot attempted a subsequent takeoff at a very low altitude.
During this takeoff, the aircraft experienced a sudden lateral loss of control. The pilot attempted to counteract a rightward yaw by increasing altitude and applying opposite pedal, but the aircraft began spinning rapidly around its vertical axis. The helicopter completed approximately three to four full rotations while maintaining an altitude of only 2 to 3 meters. As the pilot reduced power to descend, the aircraft's tilt exceeded the critical angle, causing the left skid to strike the ground and resulting in a dynamic rollover. The aircraft was destroyed, though all three occupants—the pilot and two passengers—escaped without injuries.
The investigation
The investigation examined the aircraft's mechanical condition, the pilot's flight experience, and the environmental conditions. Investigators found no evidence of mechanical failure or significant meteorological interference, as winds were light and visibility was good. The aircraft's weight and balance were within approved limits.
Review of the pilot's credentials revealed that the pilot was only rated for the Hughes H269, not the specific model involved in the accident. Furthermore, investigators identified discrepancies between the flight hours recorded in the owner's logs and the official flight history. The investigation also noted the pilot's low recent flight frequency, averaging only 3.3 hours of flight time per month over the preceding 90 days.
Findings
- The primary cause of the accident was a loss of tail rotor effectiveness (LTE), likely triggered by a rapid increase in collective pitch during takeoff.
- The pilot's attempt to recover from the yaw by increasing main rotor power actually increased engine torque, which exacerbated the uncontrolled spinning.
- The aircraft entered a dynamic rollover because the tilt angle became unrecoverable once the skid made contact with the ground.
- The pilot's actions during the emergency were contrary to the corrective procedures outlined in the aircraft's flight manual.
- The pilot lacked the specific type rating for the Hughes 500C on their license.
Safety action
- It is recommended that helicopter pilots engage in regular instructional training to improve their ability to detect and manage in-flight emergencies, such as loss of tail rotor effectiveness or power loss, using simulated scenarios with a qualified instructor.