On November 6, 1993, at about 0828 hours Pacific standard time, a Robinson R-22 helicopter, N803EH, was substantially damaged at Sacramento Executive Airport, California. The student pilot received minor injuries. Visual meteorological conditions prevailed for the local training flight and no flight plan was filed. The student pilot had contacted the air traffic control tower ground frequency for permission to air taxi from the south hangars. The request was approved at the pilot's own risk due to a lack of visual contact by the tower of that area due to visual obstruction from hangars. A radio call to the tower from another aircraft with visual contact advised that the helicopter had rolled over on its side during hover. According to the operator, the student was preparing to depart solo to a local practice area. In preparation to lift off to a hover, he raised the collective to get the helicopter light on the skids. At this point, the helicopter began to yaw. The student pilot overcorrected causing the helicopter to spin. The right rear skid caught the surface causing the helicopter to roll over. The pilot/operator reported no mechanical malfunctions or failures.