On Thursday, June 24, 1993, at about 1445 eastern daylight time, a Robinson R22, N8557Y, piloted by Mr. Richard Kirkham, collided with the terrain while at a hover at the Sanford Airport, Sanford, Maine. The helicopter was substantially damaged. The pilot was not injured. Visual meteorological conditions prevailed at the time and no flight plan had been filed. The flight was being conducted under 14 CFR 91. According to the pilot's statement on the NTSB Form 6120.1/2: ...I was practicing left pedal turns in an..area about 500' southeast of runway 7/25 which was inactive at the time. The surrounding terrain is flat with no obstructions and supports bushes which range from 6" to 12" and pose no problem to hovering and/or landing rotorcraft...I was in a stable hover between 3' and 5' while facing east. I executed a 90 degree pedal turn to a stop while facing south. The helicopter seemed to roll to the right so I compensated with left cyclic...the main rotor contacted the ground and the helicopter rotated 180 degrees around the main rotor shaft... The pilot had a total of 27.5 flight hours in rotorcraft and this make and model helicopter.