Originally Posted by
212man
Not sure I follow the logic. I understand the drive principle but I don’t understand why manual throttle would be any different - you are just replacing the AFCU with your left hand and adjusting fuel flow to meet power demand. Doesn’t matter if the Ng is fixed or not?
Yes, there are a couple of emergencies on the Gazelle that require taking the throttle out of the gate and selecting a power manually.
The only difference is that on a free power turbine the datum maintained is usually Nf while on the fixed spool engine the datum is Ng - other than that the fuel flow is still altered to maintain that datum with the capability of a manual over-ride in case of malfunction.
It's certainly not as easy with a roof mounted throttle as it is with a collective mounted one though.