On April 3, 2010, about 1330 central daylight time, a Mitsubishi MU-2B-26A, N29WD lost directional control and veered off the runway while landing at the Princeton-Caldwell County Airport, Princeton, Kentucky. The private pilot received minor injuries and the airplane sustained substantial damaged. Visual meteorological conditions prevailed and an instrument flight rules flight plan was filed for the 14 Code of Federal Regulations Part 91 business flight from Garfield County Regional Airport, Rifle, Colorado, to Princeton, Kentucky.The pilot stated that as he turned from base to final to land on runway 23, the windsock showed little to no wind and his approach speed was 95-100 knots. After crossing the threshold, the rear tires touched down on centerline about 800 feet down the runway. He stated that the landing and position on the runway was textbook perfect and that there was no crosswind during the final approach or touchdown. The pilot further stated that approximately 100-200 feet after touchdown during the landing roll at about 70 knots, the airplane made a sharp veer (30 degrees) to the right, the right wing dropped suddenly and the airplane exited the right side of the runway. The pilot thought that that he could not stop the airplane before going into a ditch so he applied full power in an attempt to fly over the ditch, but the airplane collided with a fence. After the accident, the pilot reported that he believed that something caused the power to drop or the propeller changed pitch on the right engine which resulted in the sharp veer to the right. A Federal Aviation Administration inspector reported that the airplane's wings and fuselage were buckled. Examination of the runway by the inspector showed tire marks approximately 400 feet down the runway from the initial touchdown point and the marks continued approximately 1,500 feet off of the right side of the runway through grass until the airplane collided with the fence. The left main tire was found inflated, and the right main tire was impact damaged and separated from the rim bead. The nose wheels were inflated and there were no signs of tire failures. The nose wheel steering linkages were intact and no anomalies were noted. All landing main landing gear linkages were intact with some impact damage. Examination of the engine power and propeller controls revealed no anomalies. Flight control continuity was established throughout the flight controls to their respective control surfaces, and the flaps were found set in the 20-degree position.