Terminology
I think we should all think carefully about..
N1/Ng
N2/NP
N3/Nr?
Goes to show standardisation is required..
Hated Torque matching 212 - 3B engine with TCU. 412/212 with ITT trim better but can lead you away... PTGs obviously don't match perfectly and one OHC unit against a almost timex unit can be interesting. PWAC removed field cleaning from MM so orifice clean no longer an option
Back to original question.
Most twins have overspeed protection of some sort. Singles driveshaft failure will be interesting...
Revert to the pilots...