Abstract: Employee #1 and a coworker were trimming trees in an orange grove using a topper pulled by a tractor. The topper, which rode on two wheels, consisted of a vertical mast and framework with a horizontal saw boom and an attached enclosed operator station. The horizontal saw boom, which held six rotating saw blades on two tables on its underside, could be rotated from front center to 90 degrees right and back. The boom could be rotated, raised, lowered, and angled hydraulically. The operator station, which sat back and to the left about 8 ft high on the vertical mast, could be raised hydraulically with the horizontal saw boom to about 16 to 18 ft. The tractor and topper had come out of a row and were turning right to go into the next row. The ground had a slight 5 to 10 degree decline to the left. A shaft running from the bottom of the carriage into the hydraulic tank structure above snapped, and the topper, from the tank up, fell to the left. Employee #1, the operator, was pinned under an angle iron piece of frame and suffocated.