On December 11, 2006, about 1407 eastern standard time, a Navion Navion G, N33FL, owned and piloted by a private pilot, sustained substantial damage on impact with terrain when the landing gear collapsed during landing at Baisden Airport (4OI9), Coalton, Ohio. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under 14 CFR Part 91. The pilot was uninjured. The flight originated at approximately 1340. The pilot reported that he was staying in the pattern to perform takeoffs and landings on runway 36 (2,600 feet by 60 feet, turf). He reported that on his first landing, the left main landing gear failed to lock down. He stated he was able to keep the airplane on the runway for a distance of approximately 150 feet, where the airplane departed the right side of the runway. The pilot stated that the airplane's right wing struck a fence post, causing the outboard portion of the right wing to separate from the airplane, and the airplane came to rest on a westerly heading. The pilot reported that he was able to close the fuel mixture and turn off the ignition switch. An investigator from the Federal Aviation Administration (FAA) arrived on the scene after the accident. When the FAA inspector arrived on-scene, the airplane had already been moved from the accident location to a nearby hangar. The airplane was resting in the hangar on both extended main wheels and the extended nose wheel. A functional test of the landing gear system was not performed. The inspector noted that the right wing was separated approximately 6 feet in from the wing tip, the left wing was damaged, and the propeller was damaged. The inspector also reported that the throttle was in the full open position and the mixture control was in the full rich position. In the Aircraft Crash Report supplied by the Ohio State Highway Patrol, scars from the accident airplane's propeller were noted in the ground and continued for approximately 98 feet, ending approximately 150 feet short of where the airplane came to rest. During a conversation with a Federal Aviation Administration inspector, the pilot stated that he did not extend the landing gear and landed gear-up.