Sikorsky S-76C++ N798P accident near Gulf Of Mexico, GM

Probable cause

The pilot's failure to fully land the helicopter prior to entering a turn in strong, crosswind conditions, which resulted in a dynamic rollover.

NTSB analysis

The pilot made an approach to the off-shore platform landing pad directly into a 30-knot headwind. Upon landing, the tail rotor was blocking the emergency exit, so the pilot maneuvered the wheeled helicopter approximately 70 degrees to the right while the copilot made sure the tail rotor was clear of the exit. As the pilot was completing the turn, the helicopter began to roll rapidly to the right and onto its right side. The main rotor blades made contact with the platform and the helicopter was substantially damaged. Data downloaded from the flight data recorder and enhanced ground proximity warning system revealed the pilot did not fully land the helicopter prior to the ground taxi and still had a high power setting, a high nose attitude, and the collective was not in the full down position as it was being repositioned. As a result, the helicopter entered a dynamic rollover.

Text from the NTSB. Open the NTSB docket for CEN10FA079 for the full record.