The solo airline transport pilot was landing on a gravel-covered airstrip. While on final approach, the airplane “encountered a sinker” and began to descend below his anticipated approach path. He added full engine power to stop the descent, but the airplane continued to descend, landing hard on the right side of the runway. During touchdown, the airplanes landing gear collapsed, and it continued to slide for about 150 yards, resulting in substantial damage to the fuselage. The pilot reported that there were no pre-accident mechanical problems with the airplane. A weather observation 14 miles south of the accident site reported wind from 110 degrees at 24 knots, gusting to 35 knots 12 minutes before the accident.
