I think we have touched on this before and it is an area that seems to lead to many misconceptions.
In fact, FADEC controlled engines do not limit engine power any more than a normal Hydro/Mechanical FCU (or Pneumatic/mechanical). Think about it: how many topping checks have you done in your career? What does a topping check demonstrate? Come the day you wish to avoid hiting the ground and want to pull the collective under your armpit, how much power will a conventionally governed engine give you? The 2.5 minute rating, and no more! Unless you revert to manual control, but I think that's a little far fetched and not really within the scope of the argument.
FADECs try and respect gear box and engine limitations as best they can. They do, though, recognise conditions where the pilot is obviously demanding more power than is normally acceptable (Nr drooping, rate of change of collective pitch etc) and will then normally revert to 'blow away' power (Sikorsky expression). This is usually the single engine limits being available when twin engine. This is exactly the same as a normally governed engine. Actually, it is probably beter; FADECs' precise fuel scheduling and modern materials use have allowed higher ratings called super contingency (normally a 30 second limit) to be used which offer more power than a standard 2 or 2.5 minute limit.
Another misconception is that the time limits are applied by the FADEC; they are not! If you want to pull the 30 second rating for 3 minutes, you can. You will be warned in some way (caption or flashing light etc) but the FADEC will not overide you.
Of course, we could revert to good old fashioned designs like the 212 where the FCU starts to bleed P3 air off to limit the torque at 104.3% to stop you damaging the gear box (regardless of what damage is done to the airframe and your little pink bodies!)
I think this topic shold be included in the 'Urban Myths' that Nick started a while ago.
FADECs do NOT overide the pilot in any way more limiting than a conventional governor.
