19980511037189A

(.4) The pilot was receiving instruction from a flight instructor for the purpose of practicing touchdown autorotations towards attaining his instructor certificate. The pilot said that during the autorotation, the helicopter touched down hard on the left main landing gear. The left skid then separated and the helicopter rolled over to the left. The pilot said there was no mechanical malfunction with the helicopter, and the accident could have been prevented if the flight instructor had taken the controls. He said the instructor was a relatively new instructor. The pilot also stated that the flight instructor might have been hesitant to correct a more experienced pilot. The instructor reported over 440 hours of rotorcraft flight experience including, 41 hours in make and model. The pilot reported over 3,420 hours of rotorcraft flight experience, including 63 hours in make and model. Several attempts were made to contact the instructor without success. (-23) pilot initiated a power recovery autorotation at approximately 50' AGL. Instructor told pilot to flare. Flare initiated and pilot attempted to join rotor & engine RPM. Aircraft had a high sink rate, fell through, and st ruck ground hard, rolling on left side.