Incident Summary
During an approach to an offshore platform at approximately 100 feet above ground level, the pilot experienced a shudder and heard an engine-out horn and a low-rotor-rpm warning. The pilot turned away from the platform, deployed the emergency floats, and initiated an autorotative landing. However, the floats were not yet fully inflated when the helicopter contacted the water, causing it to immediately flip inverted.
Investigation Findings
Examination of the helicopter revealed that the outer shaft in the free-wheeling unit had failed at the spline area. This failure allowed the engine to overspeed, after which it automatically shut down.
No Additional Details
The source does not specify the aircraft type, registration, number of occupants, injuries, damage extent, date, operator, location, time of day, weather conditions, or ATC involvement. Accordingly, these details are not included.