Abstract: The logging crew was "yarder" logging with a motorized carriage using a slack line system of the main line. Employee #1, a choker setter, was pre-setting four chokers. Employee #1 set three chokers while the rigging slinger and other choker setter were rigging another turn. Once the turn was landed and the logs were lying on the landing Employee #1 went under the skyline to set his last choker. When the yarder operator slacked the main line, the carriage drifted down the skyline (malfunctioned carriage brakes on the skyline). The yarder operator hit the foot brake pedal to stop the carriage. When the carriage stopped abruptly it created a whip in the skyline. Employee #1 was under the skyline on a ridge and the skyline was approximately 30 ft to 40 ft above. The whip of the skyline sent the skyline down over Employee #1 and struck him on the top of his hard hat. Employee #1 was driven to the ground due to the impact. Employee #1 was able to get up on his own and walk out of the unit. Once on the landing the "hook tender" made a decision to have the chaser transport Employee #1 to the hospital where he was admitted for diagnostic testing and determined to have fractured and crushed vertebrae. Employee #1 was hospitalized.