On June 20, 2007, about 0930 mountain daylight time, a Cessna 185C, N391M, experienced a gear collapse during an engine-out emergency landing near Kalispell, Montana. The airline transport pilot, who was the sole occupant, was not injured, but the airplane, which is owned and operated by the United States Department of Agriculture Forest Service, sustained substantial damage. The 14 CFR Part 91 public-use personal proficiency flight, which departed Kalispell City Airport about 25 minutes prior to the accident, was being operated in visual meteorological conditions. No flight plan had been filed. According to the Forest Service, the pilot was practicing a simulated engine-out approach to a 1,800 foot private grass airstrip, with the intention of executing a go-around once he reached 100 feet above ground level (agl). During the approach, the pilot maintained a manifold pressure of about 12 inches, so that the engine would still be producing a small amount of power, and the throttle would not be completely closed. When the airplane reached a height of about 100 feet above the ground, the pilot moved the throttle partially forward in order to execute a go-around, but the engine rpm did not increase. The pilot then pushed the throttle full forward, but the propeller continued to only windmill. By the time the pilot determined that the engine had lost all power, it was too late to put the airplane down on the grass strip. The pilot therefore elected to make an emergency landing in a field past the departure end of the grass strip. The field where the airplane touched down was rough and uneven, and covered with high vegetation. About 15 feet beyond where the main landing gear came in contact with the terrain, the structure inside the right main landing gear attachment box failed, and the right main landing gear leg collapsed. When the right main gear leg collapsed, the right wing came in contact with the terrain. During a post-accident inspection of the airplane and engine, no anomalies could be found that would have lead to a loss of power. After the inspection, the Continental Motors IO-0470-F engine was started and run without any malfunction detected.