What happened
On February 26, 2024, at approximately 22:15 UTC, a Bell 206-L3 helicopter, registration HK4810, was conducting a non-scheduled tourism flight at the Santa Débora helipad (SQDS) in Medellín, Colombia. After completing a previous leg of the flight, the aircraft was prepared for departure with five passengers on board.
As the pilot initiated the takeoff by applying collective to achieve a high hover, the aircraft was affected by wind conditions that caused the nose to drop. This triggered a rightward yaw that intensified as the aircraft experienced loss of tail rotor effectiveness. The pilot lost control of the helicopter, which subsequently struck a building and a mobile communications antenna. The aircraft came to rest in a vertical position with the nose facing the ground. While the pilot and one passenger were uninjured, the impact resulted in one serious injury to a passenger and several minor injuries to others.
The investigation
The GRIAA investigation examined the flight sequence, the pilot's experience, and the environmental conditions at the time of the accident. Investigators analyzed the aircraft's maintenance records, which showed the helicopter was airworthy, and reviewed the pilot's flight logs, noting that while the pilot held valid licenses, they had relatively limited experience on this specific airframe.
The investigation also focused on the operational environment of the Santa Débora helipad, a confined site characterized by complex terrain and unpredictable wind patterns caused by surrounding buildings and topography. The analysis of the wreckage revealed substantial structural damage to the tail boom, main rotor blades, and landing gear, as well as damage to the surrounding telecommunications infrastructure.
Findings
- The primary cause of the accident was the loss of tail rotor effectiveness during takeoff, driven by an inadequate takeoff technique in the presence of a tailwind.
- The pilot failed to identify the onset of the aerodynamic phenomenon and did not take corrective action.
- There was a failure to perform a real-time risk assessment regarding the changing wind direction and intensity at the helipad.
- Inadequate flight planning contributed to the event, as the crew did not sufficiently account for the aircraft's performance limitations, weight, and balance, or the specific meteorological challenges of the site.
- Operational pressures may have influenced the crew to proceed with the takeoff despite adverse conditions.
- The operator's risk management was insufficient for operations at a high-altitude, confined helipad with complex wind profiles.