Incident Overview
A helicopter was taking off from an oil rig platform. The pilot initiated the takeoff from a location necessitated by the position of a gas separator on the platform. At the time of takeoff, a left crosswind was present at approximately 30 knots, with gusts ranging from 35 to 40 knots.
Sequence of Events
After lifting off to a hover, the helicopter encountered wind gusts. According to the pilot, the aircraft turned 10 to 15 degrees to the left and banked approximately 10 degrees to the right. The gusts then subsided slightly, allowing the helicopter to stabilize momentarily in a level attitude. However, additional gusts were encountered shortly thereafter. The pilot reported that the aircraft rolled approximately 15 degrees to the right, at which point he ran out of available left cyclic control input. The pilot then lowered the collective, but dynamic rollover could not be avoided.
Outcome
The event resulted in dynamic rollover, following the sequence described. No further details on aircraft damage or injuries are provided in the source.