On March 21, 2010, about 1905 Pacific daylight time, a Beech 58P, N580TC, sustained substantial damage following the collapse of all three landing gear during landing rollout at the Santa Barbara Municipal Airport (SBA), Santa Barbara, California. The airline transport pilot and his four passengers were not injured. Visual meteorological conditions prevailed at the time of the accident, and a flight plan was not filed. The cross-country flight, which was being operated in accordance with 14 Code of Federal Regulations Part 91, had departed the San Jose International Airport (SJC), San Jose, California, about 1745, with SBA as its destination. In a telephone interview with the NTSB investigator-in-charge (IIC) shortly after the accident occurred, the pilot reported that on final approach he observed "three green lights," which indicated that all three landing gear were down and locked; he added that he did not hear a landing gear warning horn either. The pilot further reported that upon touching down and after rolling out between 500 and 1,000 feet down the runway, the nose gear collapsed followed by the left and right main landing gear collapsing. The airplane came to rest on the runway and just off to the right of centerline. A Federal Aviation Administration (FAA) airworthiness inspector, who conducted a post accident examination of the airplane, reported that both main landing gear inner doors were damaged, but neither of the outer doors sustained any visible damage. The forward pressure bulkhead was substantially damaged. During a post accident examination and repair of the airplane, a certificated Federal Aviation Administration (FAA) airframe and powerplant mechanic reported that he did not identify a mechanical failure or malfunction that could be attributed to the landing gear collapse.