Accident Overview
A certified flight instructor (CFI) was preparing a flying pilot for a commercial helicopter check flight. The training involved practicing pinnacle and confined area landings to a small, elevated Forest Service landing platform situated along a ridge line at 4,750 feet mean sea level (msl).
Performance Context
Helicopter performance tables, based on the helicopter's weight and environmental conditions, indicated a maximum out-of-ground-effect hover altitude of 6,000 feet msl.
Accident Sequence
The pilot executed a very shallow approach to the landing platform and established a hover. At that point, engine manifold pressure increased, and the low rotor rpm horn sounded. The helicopter then settled onto the landing platform. The flying pilot informed the CFI that the landing skid on his side was not positioned on the platform. The pilot maneuvered the helicopter forward, off the platform, and downslope. The low rotor rpm horn stopped sounding, and the helicopter increased forward speed but did not gain altitude. The right skid contacted some snow, causing the helicopter to flip over.
Final Position and Damage
The helicopter came to rest facing uphill on its left side. Damage included the tail boom and main rotor blades.
Mechanical Status
The CFI stated that the helicopter had no mechanical malfunctions or failures during the flight.