On May 16, 1993, at 2200 Alaska daylight time, a wheel equipped Cessna 172K airplane, N736BY, registered to and operated by the Pilot in Command, crashed short of an unimproved airstrip near the Rohn Roadhouse located on the Tatina River. The personal flight, operating under 14 CFR Part 91, last departed the Rohn Roadhouse, Alaska, and the destination was the accident site. No flight plan was filed and visual meteorological conditions prevailed. The Commercial Certificated Pilot in Command and the passenger were not injured, and the airplane received substantial damage. According to the Pilot in Command, the airplane was equipped with a Sportsman STOL kit and he was using a final approach airspeed of 45 knots. He made a number of low passes over the airstrip and noticed only light "bumps." While on short final, and just prior to touchdown, the airplane began to sink and he applied a boost of power, but not full power. The airplane struck the ground about 50 feet short of the airstrip in rough terrain. The nose gear sheared off and the airplane nosed over.