What happened
A pilot was undergoing transition training in a helicopter accompanied by a flight instructor. During the session, the pilot initiated a simulated hydraulics failure that was out of sequence with the established flight-training guide. The pilot initially landed the aircraft on the ground without incident.
While the hydraulics remained disabled, the instructor directed the pilot to perform a hover-taxi of approximately 100 feet, execute a left pedal turn, and taxi back to the starting position. Although the pilot successfully hovered forward, control of the aircraft was lost during the turn intended to return to the start point. The instructor attempted to recover the aircraft, but the helicopter rolled and the main rotor blades struck the terrain. Following the turn, the aircraft's orientation resulted in a 14-knot tailwind.
The investigation
An examination of the wreckage showed no anomalies prior to the impact. Subsequent testing performed on the hydraulic servos indicated high fluid flow rates, but investigators found no operational deficiencies in the system.