20060724016819I

(-23) On approach to Isla Grande Airport in San Juan, p.r. pilot noted that the right main landing gear light was not illuminated. Pilot elected to go around and requested visual gear position from control tower. They responded that gear appeared to be down and locked. Pilot cycled the gear and emergency procedures followed. Landing was accomplished on left main gear followed by right and nose gear. Right gear stated to collapse after several seconds down the runway. The aircraft skidded off the right side, entered grass area between the runway and the taxiway. Pilot left the aircraft without injury. Pilot's statement: flight departed st. thomas on a VFR flight to puerto rico, with the pilot as the sole occupant. On approach to tjig I noted that the right main landing gear light was not illuminated. I elected to go around and in the process a low approach was accomplished. In the process of this procedure, I requested that the tower make a visual assessment of the right main landing gear. They responded that the gear appeared to be down and locked. The tower was notified that I would be leaving the traffic pattern to the north to troubleshoot and accomplish the necessary checklist. The landing gear was cycled, the emergency gear extension procedure was followed and several high "g" manuevers was accomplished to no avail. The control tower was notified that I would be returning to the airport. The emergency vehicles were already positioned for my arrival. Touchdown was made on the left main gear followed by the touchdown of the right main and the nose gear. After approximately three seconds the right main gear started to collapse. The throttle, props, and mixture controls were moved to the idle/cutoff position. The aircraft skidded off the right side of the paved runway surface contacting one to two runway edge lights and entered a grassy area between the runway and a parallel taxiway. The aircraft was secured and I exited the aircraft without any injury.