The airplane experienced a loss of engine power and force landed in a park at about 0840 Mountain time. The commercial pilot was not injured, but his passenger sustained minor injuries. The airplane was substantially damaged. Visual conditions prevailed. About 30 minutes into a planned 45-minute flight, the pilot felt the engine vibrating. He decided to return to his departure airport. Joining the downwind leg, he heard a loud “bang.” The engine then lost power and he was no longer able to maintain altitude. The pilot made a 180-degree turn to land in an adjacent park. During final approach, he observed someone walking on his intended landing area, banked the airplane to the left and landed. During the ground roll, the airplane collided with a restroom facility on the park property.
