Abstract: A carpenter for Six Flags Magic Mountain Amusement Park was using 76-millimeter square clips to set steel tracks on a 12.2-meter incline of the Colossus roller coaster. He was crossing the steel tracks to set the clips on the outside tracks when he stepped onto an intermediate 100-millimeter by 150-millimeter ledger board. He slipped and fell head first through an 850-millimeter by 710-millimeter opening. As he fell, he grabbed at a dangling drill motor cord, which was attached to the upper structure, and flipped right side up. He also tried to grab the support structure, which slowed his fall. The employee landed on his right foot and rear end. He was hospitalized for his injuries for 2 days.