On Apr 24, 3:47 pm, "Mike Isaksen" wrote:
wrote in message ...
That is, while the FADEC itself probably doesn't require much
in the way of power, how much power does it take to manipulate
the throttle, mixture, and prop?

The answers to those kind of questions seem to be missing from the public
record, and even the public discussion. [..]

We had a large discussion of FADEC right here last November.
Unfortunately, non-engineer types decided to hijack the discussion,
mostly because they wanted to bash anyone who agreed with Mxsmanic
that all-electronic systems can have major failure modes. (Ever have
your car engine stop because of a failed sensor? I have.)

At that time, I wrote "Losing all power (including the battery backup)
on a FADEC means your engine stops."

Multiple people (who I will not name because they should rightfully be
embarrassed, but they post here a lot) threw insults at the very idea
that this could happen.

In any case, the FAA deems that EECs (Electronic Engine Controllers)
should fail such that the engine is producting at least 85% power.
EECs are just engine aids, however. Full authority FADECs have no
such requirement. Instead, they are supposed to have backup
batteries and/or alternators. Just like the DA-42, basically.

Regards, Kev