On September 10, 2015, about 2035 central daylight time, a Beech 58 twin-engine airplane, N4199S, sustained substantial damage while landing at Gary/Chicago International Airport (GYY), Gary, Indiana. The pilot, the sole occupant, was not injured. The airplane was registered to Charity Homes, Inc., and operated by Midwest Air Link under the provisions of the 14 Code of Federal Regulations Part 135 as a non-scheduled domestic cargo positioning flight. Night visual meteorological conditions prevailed at the time of the accident, and the flight operated on an activated instrument flight rules flight plan. The flight departed the Columbus Municipal Airport (BAK), Columbus, Indiana, about 2030 eastern daylight time en route to GYY. The pilot reported that he was flying the runway ILS 30 approach to GYY when he lowered the approach flaps about 5.5 miles from the airport and lowered the landing gear 5 miles from the airport. He reported that as he was turning off the positioning lights, so that the landing gear indicator lights would brighten, the propellers struck the runway and the airplane skidded on its belly on the runway. The pilot closed the throttles and mixture, and turned off the master switch. The air traffic controller who was in the GYY control tower reported seeing the nose landing light before the airplane touched down. The examination of the airplane revealed that the airplane's wing spar sustained substantial damage. The belly panels, flaps, and nose landing gear doors sustained scraping damage consistent with contact with the runway. The damage to the nose landing gear doors was consistent with the nose landing gear in the retracted position. There was no damage to the inner or outer landing gear doors. A Federal Aviation Administration airworthiness inspector provided oversight when the landing gear system was examined. The airplane was put on jacks and the system was checked by lowering and raising the landing gear handle in the cockpit. The main and nose landing gear lowered and raised normally, and the landing gear light indicators operated normally as well. At 2045, the surface weather observation at GYY was: wind 290 degrees at 5 kts, 20 miles visibility, sky clear, temperature 17 degrees C, dew point 14 degrees C, altimeter 29.92 inches of mercury. The landing checklist is accomplished after the landing gear is lowered and the airplane is in the landing configuration. While on short final and in the flare, if there are doubts about the landing gear configuration, a go-around should be accomplished.