On July 30, 1997, at 1600 central daylight time (cdt), a Boeing B75N1, N75939, operated by a commercial pilot collided with the terrain following a loss of control while landing at the Tri- County Regional Airport, Lone Rock, Wisconsin. The airplane was substantially damaged. The pilot was not injured. Visual meteorological conditions prevailed and it is unknown if a flight plan was filed. The airplane departed from Norman, Oklahoma, at 0630 cdt. The pilot reported that during the landing roll the airplane veered "uncontrollably" to the right. During the turn the left wing contacted the ground. The airplane continued the turn until it came to rest on its nose, 180 degrees opposite the landing direction. Post accident inspection of the airplane by a Federal Aviation Administration Airworthiness Inspector revealed the crankcase breather tube was routed down the right main landing gear strut thus allowing oil residue to contaminate the right brake.