On September 10, 2007, at 0838 mountain daylight time, a Cessna 402B, N402BF, operated by Aero Charters and Transports, was substantially damaged during the landing at the Lea County Regional Airport (HOB), Hobbs, New Mexico. Visual meteorological conditions prevailed at the time of the accident. The non-scheduled domestic cargo flight was being operated on an instrument flight rules flight plan under the provisions of Title 14 Code of Federal Regulations Part 135. The airline transport pilot was not injured. The flight originated at Roswell International Air Center, Roswell, New Mexico, at 0800. The pilot reported that on approach into HOB, he put the landing gear handle down and the left main landing gear indicator light failed to illuminate. The pilot notified the air traffic control tower and executed a go around. The pilot then raised the landing gear handle and lowered it again with the same result. During final approach the pilot reduced power on the engines to check the gear unsafe audible warning. The warning did not sound and the pilot elected to land the airplane with the unsafe gear indication. The pilot requested that tower controllers confirm that the landing gear was down. The controllers informed the pilot that the gear appeared to be down. On landing, the left main landing gear collapsed. The airplane departed the side of the runway and struck a taxiway sign, coming to rest approximately 1,800 feet from the approach end of the runway. An examination of the airplane by the Federal Aviation Administration revealed the left wing forward and rear spars were damaged, the left wing leading edge was dented about mid wing and outboard, the left horizontal stabilizer and spar were damaged, and the right wing main spar was damaged. The examination also showed that the left main landing gear down lock was broken. The down lock was retained for further examination by the National Transportation Safety Board's Materials Lab. Examination of the fracture surfaces on the down lock were clean and exhibited signs consistent with an overload event. An examination of the remaining airplane systems, by the FAA, revealed no anomalies.