On February 27, 1994, at 1100 hours Pacific standard time, a Bell 206B helicopter, N50PE, main rotor blades severed the tailboom assembly while demonstrating a hovering autorotation at Agua Dulce Airport, Agua Dulce, California. The pilots were conducting a local visual flight rules instructional flight. The helicopter, registered to and operated by the dual student pilot, sustained substantial damage. Neither the certificated commercial pilot/flight instructor, the dual student pilot, nor the two passengers were injured. Visual meteorological conditions prevailed. The flight originated at Van Nuys Airport, Van Nuys, California, at 0930 hours. The Los Angeles County Sheriff's deputies reported that during the autorotation the helicopter slid about 5 feet in the soft, sandy terrain. During the slide, the front (toe) of the main skids dug into the soft terrain precipitating the nose-down condition. The main rotor blades severed the tailboom and the helicopter settled onto its landing skids with no further damage. The pilot submitted the required Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2, to the National Transportation Safety Board, Southwest Regional Office. The pilot confirmed the Los Angeles County Sheriff's deputies' report and added that the hovering altitude was between 3- and 5-feet skid height above the ground. He also said the terrain was grass and dirt.