212man
I agree with what you are saying. I would expect that the total loss of one channel would need some sort of indication to the pilot even though it is in essence a loss of redundancy but I found out the hard way that is not the case. If channel A which is the primary fails there is no indication to the pilot as he/she still has a totally functional FADEC control system on channel B so there is no cockpit indication. I have actually asked that this be changed but I am far enough down the food chain not to make a difference just yet. So the indications and there purpose are:
Flashing amber after shutdown (N1<20%) = loss of redundancy
Steady amber during flight= loss of a signal which has no back up in which case we switch to a back up law (mathematical formula that gets us close). The FADEC continues to control the engine but since we are using a back up law the engine may not perform quite as well as normal but is still under automatic control.
Red Gov light anytime during flight= metering valve is frozen and no further fuel flow changes made by the FADEC system. On the EC130 since we have the EBCAU system, the output from the FADEC comuter that turns on the Red gov light also goes to the EBCAU to activate it which turns on the Amber GOV light. With this in mind if the system is working properly you should never get a red GOV light without the amber as this would mean the FADEC is not controling the engine nor is the EBCAU!!
I don't work with the EC155 much so I dont remember if it has a dual channel or single channel system (I know the EC155B has the dual channel Arriel 2C2 engine but not sure about the 2C1 powered aircraft). This could be where the difference comes into play. If you would like I can check to see if this same caution warning display methodology applies to the 155's as well. Turbomeca is pretty good about using the same ideas for all their systems but those little changes and assumtions are the ones that bite you!
Max