The airline transport pilot had been holding short of the runway and was taxiing onto the runway to begin his takeoff from a standing start. As the airplane was half way through its 90 degree left turn the right main landing gear collapsed and the right wing and the right horizontal stabilizer struck the ground. There was substantial damage to the airplane. The pilot, who was the only occupant, was not injured. The FAA inspector who responded to the accident scene said the pivot pin was missing from the bellcrank on the right main landing gear side brace lock link. According to maintenance records this airplane had flown only four hours in the previous 40 months. The airplane had flown two hours in the nine days since the most recent annual inspection had been completed.