Originally Posted by
KenV
OK, that makes sense. Thanks for the feedback. But from what I'm gathering from your description it sounds like they are indeed like the power levers on a multi-engine fixed wing aircraft. So the pilot is not really controlling fuel flow, he is controlling engine RPM which in turn controls rotor RPM. In the jet (and multi-spool turbo prop aircraft) controlling RPM controls thrust. Fuel flow remains under the control of the ECU/FADEC.
Not quite. The Hydromechanical unit (HMU) controls fuel flow in a course way, the ECU (later DECU) fine tunes it and adds a variety of other features and protections.
In some ways, yes, you aren't using the throttle (PCL) to fine tune the fuel to the engines, since the HMU acts like a governor using thing like NR, Ng, P3, T2, to position the metering valve.
In the LockOut mode, none of the ECU/DECU signals get to the HMU. You are back to using a coarse governor to position the metering valve to get the fuel to the engine. Your NR will vary as you change load, which it doesn't tend to when the ECU/DECU is doing its thing.
Apologies for the digression, gents.
My initial question was answered.
@ Loma:
checking software throughout the fleet, might it be as simple as checking what
software versions are displayed
It is not beyond the realm of possibility that they have already sent their customers maintenance files (diagnostics), which would be loaded into their test/calibration kits (ground based maintenance, not inflight). The maintenance team would perform a check to see if a given install passes the diagnostics.
That's a guess, based on old maintenance experience.