From an Old Tractor website

[Kevin McCormack]

Richard, a friend of ours was nearly killed years ago while pulling a long section of downed tree trunk with a log chain. He was apparently going at a pretty good clip on the tractor when the facing end of the log struck a rock embedded in the earth. The log stopped dead, the torque forced the tractor to rotate upwards and back over the rear axle, and pinned him against the steering column by his pelvis and upper thigh. He narrowly missed losing that leg and spent weeks in the hospital with surgical pinning, etc. to save it.