On October 3, 1993, at 1823 mountain daylight time, a Cessna T182RG, N999RG, registered to the pilot, impacted terrain while landing at Casper, Wyoming. A VFR flight plan was filed for the business flight, conducted under 14 CFR 91 in visual meteorological conditions, that departed Jackson, Wyoming, on October 3, 1993, at 1540. The ATP certificated pilot was not injured in the accident. The aircraft was substantially damaged. There was no fire. When the flight arrived at Casper, the pilot attempted to lower the landing gear while on approach and the main gear would not extend. The aircraft landed on the nose gear, slid off the runway and impacted terrain. Mechanics were able to determine after the accident that the failure of the landing gear to fully extend appeared to have been due to a leak in a hydraulic line (Cessna part number 228001-13), caused by it rubbing against the throttle cable.