What happened
The helicopter was operating near its gross weight limit at the time of departure. The pilot estimated the ambient temperature at the helipad to be approximately 90 degrees Fahrenheit, conditions that significantly impact rotorcraft performance. As the aircraft lifted off the ground, the pilot initiated a left pedal turn, a maneuver that requires additional engine power to maintain control and altitude.
Despite applying full engine power, the helicopter was unable to sustain its altitude in the high-density-altitude environment. The aircraft descended down the hill away from the helipad. During this uncontrolled descent, the left skid made contact with a tree stump. This impact caused the helicopter to roll over.
The investigation
The investigation focused on the operational conditions at the time of the accident. Key factors included the proximity of the aircraft's weight to its maximum limit and the high ambient temperature which reduced engine performance and rotor efficiency. The pilot's assessment of the weather conditions was verified as accurate for the location.
Findings
The primary factor contributing to the accident was the helicopter's inability to generate sufficient lift and thrust to maintain altitude given the combined effects of gross weight and high temperature. The decision to perform a left pedal turn, which demands increased power, further exacerbated the performance deficit. The contact with the tree stump was a direct result of the failure to maintain positive climb or level flight.
Safety message
Pilots operating helicopters in hot weather conditions must carefully calculate performance limitations. Operating near gross weight limits in high temperatures leaves little margin for error during takeoff maneuvers that require additional power, such as pedal turns. Pre-flight calculations should account for density altitude to ensure adequate performance margins are maintained.