Last time I have flown the B212 was about 9 years ago so I am a bit rusty on the procedures. Last I flew the aircraft, I was the company training pilot on the 212 and 205 and was told and shown a new training procedure for the 212 but not the 205 (don't know why, 205 is in the same situation) and the procedure was called Main driveshaft failure training, here also called shortshaft or power shaft. The training was to recognize what happened in flight when the failure occur and what to do about it.
This came about due to 2 recent (at the time) accident in the US military where 2 212 crashed with lost of lives and it was found out that the problem was due to a powershaft failure AND the wrong response to it by the pic.
According to the report both pilots in both accident had the reaction of pulling collective up to slow down RPM to investigate the problem.
Doesn't take much to loose rotor RPM especially when the engines are not connected anymore to the trany and RPM would come down to a point of no recovery possible.
I do not have the paperwork related to it but it showed dual tach and different needles position depending if it was a powershaft failure or gov-overspeed etc.
Don't know if they are still training for that nowadays.
jD