Preliminary data based on the notification from the South African authorities:
The flight instructor stated that during the third autorotation, at 300ft AGL he called “opening throttle” but there was no response from the engine.
The flight instructor then took control from the student. He stated that he kept the flare for as long possible and levelled off before ground contact to prevent a tail strike. The speed at touchdown was approximately 15 knots. The ground was very uneven, and the helicopter touched down hard on the skid gear and bounced and rotated approximately 90° to the right before coming to rest in an upright position. It was during this phase that the main rotor blades severed the tail boom.