On May 19, 2003, at 1400 central daylight time, a Piper PA-22-160, N9601D, piloted by a private pilot, sustained substantial damage when it impacted terrain during landing approach to an off airport landing area near Pierre, South Dakota. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of 14 CFR Part 91 without a flight plan. The pilot and passenger were uninjured. The flight departed from Pierre Regional Airport (PIR), Pierre, South Dakota, at 1345 central daylight time. The pilot reported his airspeed abruptly dropped while on approach about eight to ten feet above ground level. The pilot stated the main landing gear collapsed upon impact with terrain and the airplane subsequently slid 40 to 60 feet. The pilot noted there were no holes in the landing surface. The pilot reported no failures or malfunctions with respect to the airplane or its systems. The weather reporting station at the departure airport reported the winds at 1353 as 340 degrees at 15 knots.