Back in 1981, the RAAF had a UH-1B which crashed. The T/R pitch change cables ran beside the drive shaft in the upper tunnel (in later models they were moved to the lower one). One cable came off the pulley and wrapped around the drive shaft, causing a full control deflection. The T/R blades flapped way past their limits and struck the fin, causing part of a T/R blade to depart the scene. This imbalanced the gearbox which tore itself out of the fin.
The resulting CG change pitched the nose down, and combined with the yaw, caused a mast bump. The main blade separated, but on its way out, it sliced through the left cockpit, bisected the copilot, removed the left door and then the tail boom. The remainder dropped / fluttered to earth, 3 fatalities.
No time to react.
