What happened
On February 21, 2021, a Robinson R44 II helicopter, registered as TG-VSL, was performing a private flight from La Aurora International Airport to a helipad at the Hotel Atitlán in the Sololá department. During the takeoff phase, the aircraft encountered a 10-knot wind from the northeast (50 degrees). As the helicopter moved over the water of Lake Atitlán, it lost control and lift, ultimately impacting the lake and becoming partially submerged. The pilot and passengers were successfully extracted from the wreckage by rescue personnel and sustained no apparent injuries.
The investigation
The investigation conducted by the DGAC/UIA examined the aircraft's maintenance records, the pilot's qualifications, and the environmental conditions at the time of the accident. Investigators found that the aircraft was maintained according to the manufacturer's program and that the pilot held valid commercial helicopter ratings and a current medical certificate. Post-accident inspections of the engine and flight controls revealed no mechanical failures or technical malfunctions. The investigation also noted that while no operational weight and balance documentation was found for this specific flight, the aircraft was not exceeding its maximum takeoff weight or center of gravity limits.
Findings
- The primary cause of the accident was an improper operational procedure during takeoff while encountering a 10-knot tailwind from the northeast.
- The tailwind likely directly affected the tail rotor, contributing to the loss of control.
- As the aircraft transitioned over the lake, the loss of ground effect, combined with the wind conditions, led to a loss of lift and control.
- The available engine power was likely at or near its operational limits during the maneuver.
Safety action
- Helicopter owners should ensure pilots are properly trained on the importance of determining wind direction and intensity during takeoff and landing, particularly regarding how tailwind conditions can critically affect the tail rotor when operating near performance limits.
- Operational safety managers should remind rotary-wing and general aviation pilots of the importance of not operating at helipads that lack proper authorization and oversight from the aeronautical authority.