This video is about three fatal helicopter crashes that all had the same cause: Low-G, mast bumping and thus in-flight breakup. In none of the cases were there technical defects, but the accidents happened because the pilots did not observe the limitations of their helicopter.
HPZ explains what mast bumping is all about and how to avoid it.

Related Links:

Types of Rotor Systems:
   • Types of Rotor Systems in Helicopters  

Interview with the elderly Frank Robinson (1930-2022):
   • Frank Robinson - Robinson Helicopters...