Abstract: At about 8:45 a.m. on February 28, 1991, Employee #1, a crane operator, was moving a Grove 100-ton, 18-wheel mobile crane to a ground level pad location when it overturned on its right side. The crane was moving slowly up 30 degree sloping ground that had a U-turn. The 1978 diesel crane (serial #41027) was equipped with a 32 ft fly section extension and a 44 ft boom base that was extended 30 degrees with the sloping ground. It appeared that Employee #1's error was his failure to lower the fly with the boom section on the saddle to secure it while the crane was being moved. Employee #1 wasn't injured, but the accident caused approximately $20,000 in damages to the crane.