Alternative to the pilot-stuffed-up theory
Hi needhelp. While the usual approach especially for a low hours instructor and student is to blame the crew for rapid stick inputs or low rotor RPM. Any thorough investigation must also consider structural failures and exclude that evidence before assigning blame. There have been investigations which may be of interest to your studies. Google SIR9603 for one, and then check A08_25_29 recommendations.
Regards
blakmax