Originally Posted by Carl Froehlich
Ok - I'll bite.
Well, actually, I do know I have 42 minutes of reserve juice should the alternator fail. This compares somewhat better than the electrical analysis spreadsheet I built for the design would suggest (I designed for 30 mins), so I'm happy. And I specifically chose to not worry about the master relay failing, because it's typical failure mode is failing "on" when it fails during operation as identified via FMEA. But all that is kind of beside the point.
The main point of my post was that your opinion was posted as fact - which is most certainly is not; it's an opinion and should probably be clearly called out as such. A well reasoned opinion, with thoughtfulness and analysis to be sure, but an opinion nonetheless that doesn't apply to many (if not the overwhelming majority) of RVs that have a single PC-680 as shown on the plans and which are flown on more than just local VFR missions daily. I think are probably more risk averse than most - nothing wrong with that - but the operational history of the RV fleet hasn't demonstrated that planes flying other-than-local-VFR missions are falling out of the sky due to electrical failure either.