On January 25, 2003, about 1745 eastern standard time, a Robinson R-22B helicopter, N7198U, was substantially damaged after landing at the Pittsfield Municipal Airport, Pittsfield, Massachusetts. The certificated private pilot was not injured. Night visual meteorological conditions prevailed and no flight plan had been filed for the personal flight conducted under 14 CFR Part 91. The pilot said he landed on the ramp and was unaware that the area was covered with ice because of darkness. He turned off the governor, placed the cyclic and collective friction locks on, and brought the engine RPM to 80 percent for cool down. The helicopter began to turn 90 degrees counter-clockwise and slide backward. The pilot applied right pedal, which countered the yaw; however, the helicopter continued to slide backward on the ice. The helicopter then contacted a snowbank and rolled over. The pilot further stated he did not experience any mechanical malfunctions. The pilot reported 205 hours of total flight experience, which included 161 hours in make and model.