On January 31, 2007, at 1140 eastern standard time, a Cessna 310Q, N20SS, was substantially damaged following a gear collapse after landing at Atlantic City International Airport (ACY), Atlantic City, New Jersey. The certificated commercial pilot was not injured. Visual meteorological conditions prevailed for the flight that originated at Easton/Newnam Field Airport (ESN), Easton, Maryland, about 1100. No flight plan was filed for the business flight that was conducted under 14 Code of Federal Regulations Part 91. In a written statement, the pilot described an uneventful flight from Easton to Atlantic City. The pilot initiated a descent, and slowed the airplane for entry to the base leg of the runway-31 traffic pattern. The flaps were adjusted, the gear was lowered, and the pilot noted that all three green landing gear lights were illuminated. Shortly after, the pilot noticed an unsafe gear indication and that two green main landing gear lights were extinguished. The pilot "recycled" the gear, initially got a safe gear indication, followed by an unsafe gear indication on the two main landing gear. The pilot notified the tower controller, who advised the pilot that the gear appeared down as the airplane over flew the runway. A Federal Aviation Administration (FAA) airplane was flying in the vicinity, and the crew overheard the conversation between the pilot and the controller over the radio. The pilot maneuvered the airplane away from the airport, and attempted to troubleshoot the problem according to the owner's manual on board the airplane. About that time, the FAA airplane was able to observe the landing gear, and the crew advised the pilot that the gear was down. The airplane returned to the airport, and landed on the runway. During rollout, the left, right, and nose gear collapsed in sequence before the airplane departed the left side of the runway and struck a sign. Examination of the airplane by FAA inspectors revealed substantial damage to the airframe. On February 29, 2008, the mechanic who completed repairs on the accident airplane in the months following the accident, was interviewed by telephone. He explained the damage to the airplane, and how he believed the sequence of events prior to landing resulted in the accident. According to the mechanic, the metal tab incorporated in the "squat" switch for the left main landing gear had fatigued and broken prior to the accident pilot moving the gear handle to the down position. As a result, the left main landing gear safe indication did not illuminate. The pilot recycled the gear, and again the light would not illuminate because the switch was broken. The mechanic believed that the pilot then retracted the gear, and deployed it manually. During the hand-crank deployment of the gear, the pilot cranked the gear past the mechanical stop, breaking it. When the airplane touched down, the left main landing gear was in an "over center" condition, and the gear collapsed which resulted in substantial damage to the airplane. The airplane was manufactured in 1972, and had accrued 3,236 total aircraft hours. The most recent annual inspection was completed December 28, 2006, at 3,222 aircraft hours. The pilot held a commercial pilot certificate with ratings for airplane single engine land, multi-engine land, and instrument airplane. His most recent FAA second-class medical certificate was issued on April 7, 2005. The pilot reported 7,295 total hours of flight experience, 3,004 hours of which were in multi-engine airplanes, and 430 hours of which were in the Cessna 310. At 1454, the weather reported at Atlantic City International Airport included clear skies and winds from 290 degrees at 14 knots, gusting to 20 knots. The visibility was 10 miles. The temperature was -1 degrees Celsius and the dew point was -13 degrees Celsius.