“ Destroyed due to T/R blade separation (manufacturing defect) in flight from 1978. out of balance gearbox allowed remaining blade to cut tail boom away aft of the horizontal stabalator. Loss of C/G led to mast bumping and loss of main rotor. Pilot did everything right - had entered autorotation, shut engine down, was headed to a clear landing site. Once C/G shifted and M/R was lost, airframe went into trees about 10' off of the ground and shredded itself 3 fatalities. I was part of the Accident Investigation Team. It led to a SOF message and dye penetrant inspection of T/R blades. ”