What happened
The pilot reported that during an approach to runway 6 at dusk, a sudden sink rate developed in the aircraft. In response, he applied power and brought the aircraft to a climb attitude. However, he felt a thud beneath the aircraft and noted that the right main gear light no longer indicated down and locked. Suspecting that the right main gear had separated, he made a go-around.
During a subsequent landing on runway 24, he shut down the engines and held the right wing up as long as possible by using the ailerons. As the aircraft slowed, the right wing settled and the aircraft went off the right side of the runway. Gouges were found short of runway 6, where the right main gear had hit the ground and separated from the aircraft.
The investigation
Examination of the site revealed gouges short of runway 6, indicating where the right main gear had struck the ground before separating from the aircraft.