At about 0900 Mountain time, the airplane was substantially damaged when it impacted terrain following a touch-and-go landing. The solo private pilot received minor injuries. Visual conditions prevailed. During the descent for landing, the pilot enrichened the mixture and entered the traffic pattern for a touch-and-go landing. After the touchdown, he retracted the flaps, added power and lifted off. The airplane was under-performing on climbout, so he enrichened the mixture, which did not rectify the problem, and he heard the engine make “popping” sounds. Despite full throttle, the airplanes airspeed was lower than normal and the tachometer indicated about 1800 rpm instead of the 2300 rpm target value. The pilot began a right turn back towards the airport, and lowered the nose to increase the airspeed, but the airplane did not seem to accelerate. The airplane impacted trees and terrain about 3500 feet northwest of the departure end of the runway and came to rest upright. Based on local conditions, the airports density altitude at the time of the accident was calculated to be approximately 6200 feet.
