It was reported that the right main landing gear leg light failed to give a safe down indication after the gear was selected down during the approach to land at Cummins. The pilot was unable to get a safe indication after using both the normal and emergency extension systems so he shut the right engine down and moved the propeller to a horizontal position prior to landing. The aircraft settled onto the right flap during the roll-out. Post-accident inspection indicated that the torque link bolt of the scissors joint of the right landing gear seized and fractured during the takeoff from Ceduna. When the landing gear was lowered at Cummins the top arm of the torque link contacted the side of the wheel well, preventing the right gear from being lowered. The grease on the torque link bolt had dried out, probably as a result of the aircraft having been left standing for a long time without use. Lack of lubrication probably led to the bolt failure.