On August 31, 2001, at approximately 1310 mountain daylight time, a Vans RV-6A homebuilt airplane, N199LH, was substantially damaged when it departed the runway during takeoff and impacted a ditch at Stevens Field (2V1; elevation 7,700 feet), Pagosa Springs, Colorado. The private pilot, the sole occupant on the airplane, was not injured. The pilot was operating the airplane under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the local personal flight that was originating at the time of the accident. No flight plan had been filed. The pilot said that he was practicing a short field takeoff. He held the brakes and set the power at 2,650 revolutions per minute. When he released the brakes, the airplane immediately veered to the left and departed the runway. The pilot said he attempted to apply full right rudder, but no right rudder was available. He said that he attempted to control the airplane with differential braking. The airport manager said that the airplane traveled approximately 350 feet, started down a hill, and struck an Elk fence (the fence was approximately 250 feet east of the runway). The pilot said that the nose wheel dropped into a ditch which was along the left side of the runway. The airplane's nose gear broke aft and the airplane came to rest in a nose down orientation. The nose wheel landing gear separated from the airplane, and the engine mount was bent. Postaccident examination of the airplane by the pilot, revealed that a headset on the floor of the airplane had jammed the rudder controls. The density altitude was calculated to be 10,347 feet.