The EC130B4 is, as stated before a true FADEC controlled engine, which also has a third electrical back up system (EBCAU or emergency back up control ancillary unit) provided by Europcopter. In the event that one channel of the FADEC would fail, the system would switch to the other channel and continue to fly WITH NO INDICATION TO THE PILOT AT THAT TIME!. This event would be considered a loss of redundancy since we have a second channel to continue to control the engine. Upon shut down in this case you would get a flashing amber GOV light which would indicate you had, in the last flight, a loss of redundancy and maintenance is required.
If for some reason you were to lose both channels of the FADEC system you would imediately get a red and an amber GOV light which indicates the FADEC is now out of the loop and the EBCAU system is activated. The EBCAU system is linked to the N2C sensor and it's sole purpose in life is to meter fuel flow to acheive and maintain 100% N2 speed (this may equate to 102Nr as previously posted). The EBCAU system is said to be very responsive but may slightly lag behind collective inputs so be cautious when flying in this mode.
The other thing to be aware of here is that the EC130 normally has a variable rotor RPM system in place for lowering noise levels. If at the time of this hypothetical dual channel FADEC failure you happen to be at a higher rotor rpm (I think 104% is the max) then you would get a red and amber light and the engine and rotor system would decelerate to achieve 100%N2 as commanded by the EBCAU. Normally this situation would prompt a pilot to react by lowering the collective (a normal response to red lights and decelerating engine/rotor) which in this case can cause an overspeed! Remember if you get the red AND the amber GOV lights it is an indication the the EBCAU is active and not abnormal for the engine and rotor to decelerate. Obviously I wouldn't let things get too far before I did something but keep it in the back of your mind.
In the worst case scenario if both FADEC channels as well as the EBCAU all failed you would be stuck with a fixed fuel flow as the metering needle would be frozen. The course of action at this point would depend on the power setting you were stuck with but you get the picture.
Truth be told there have been very few cases of dual channel FADEC failures that I am aware of. Hopefully this little lesson will help you make it home to change parts instead of changing pants if it happens to you!
Hope it helps
Max