Opening act was for 3 jumpers to exit from jump-plane (j/p) at 3500′ agl; 2 jumpers were to join at 2000′ to display flag, while 3rd jumper was to circle above. N90bc & n31485 were to circle jumpers in opposite directions. N90bc was to circle clockwise, outside turn radius of n31485, which would circle counterclockwise. When 2 of 3 jumpers exited from j/a, pilot of n31485 banked left into spiral, apparently unaware of 3rd jumper.

Read the NTSB report…