Abstract: A 45 ton rough terrain crane with a hydraulic extendible boom was being used on the flight deck of the aircraft carrier U.S.S. Nimitz. The crane had a multi-part main line and a single part auxiliary line. As the operator was positioning the crane for a lift, he lengthened the boom to put the main line hook over the lift. The lengthening boom put the auxiliary hook and line into a "two block" condition, breaking the auxiliary line and dropping the hook and ball onto Employee #1's head, killing him instantly. Although the crane operator was familiar with this general type of crane and was an experienced operator, he had not been trained in operation of this model or this manufacturer. He unknowingly turned off the anti-two block function of the load moment computer. Employee #1 was an inexperienced rigger, undergoing training on his second day in the field.