Abstract: A crane operator and Employee #1 were off-loading four concrete deadman blocks from a lowboy trailer, one at a time. The blocks were about 4 ft by 4 ft by 3 ft, and each weighed about 6,200 lb. The friction clutch crane was a 1959 Northwestern 80D, crawler mounted, with a 70 ft lattice boom. After the hoist line was attached to the last of the blocks, the operator took tension. Employee #1 gave the hand signal to raise, then moved further out beside the block. The block had been raised just off the trailer deck when the crane swung unexpectedly to the operator's left and the block struck Employee #1, driving her into the exposed tops of the rear axles. Her right leg was amputated, her left leg sustained crushing injuries, and she also suffered head trauma. The crane was not positioned on a level surface. The load swing during the accident was toward the low side--which was the direction of the planned swing, but the operator stated that the swing occurred before he planned to release the manual swing brake. Witnesses stated that the swing brake was found to be engaged following the accident. The swing brake was found to be functioning when tested in a limited test following the accident; no under load or additional test was performed due to the unknown condition of, and damage to, the crane. Non-accident-related violations included damaged boom lacing, no auto boom stop, no swing radius guarding, and no inspection by a competent person.