On April 30, 1994, at 1700 mountain daylight time, a Cessna 172N, N739CW, collided with trees while maneuvering low in a valley near Monarch, Montana. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the commercial pilot and his two passengers received minor injuries. The flight had departed from Great Falls, Montana, on April 30, 1994, at 1630, as a pleasure flight. During a telephone interview the pilot reported that he was flying the airplane approximately 50 feet above ground level, in a valley that was surrounded by mountains. The pilot stated that the airplane encountered a down draft and was forced down into the trees. The pilot reported that there were no mechanical failures or malfunctions with the airplane prior to the collision. In the pilot's written statement, he stated that the airplane was at cruise airspeed and 500 feet above ground level when the airplane started to sink rapidly. The pilot applied full power and pitched the nose of the airplane up to attain the best angle of climb. The airplane continued to sink until the collision with the trees.