> 1. What are most folks doing in their planes?

Hi Dan,  There are certainly valid arguments to be made for many different
combinations of instrument power. Here's what we did in our 320 and I'm
quite satisfied with the level of redundancy. We used vacuum horizon and DG
and electric for the turn coordinator which is also the autopilot (Stec 30).
We then provided a backup for each system, vacuum and electric. For the
vacuum we used the precise flight manifold type system. You certainly
wouldn't want to PLAN to be IFR with this system in use but I believe that
it is an excellent EMERGENCY system. It's light, fairly easy to install and
economical. For electric we have two electrical systems, a main bus and an
essential bus. Instead of the usuall single 25AH battery we used two 12AH
(B&C) batteries. Each battery powers it's own bus. For normal operations,
the busses are connected by a bus tie contactor. In the event of an
alternator failure, the bus tie would be opened and the systems would
seperate. Having only truly ESSENTIAL stuff on the essential bus assures
that we would have electricity to that bus for about 4 hours in the event of
an alternator failure. The weight of this dual battery system is just
slightly more than a single battery system yet it provides, in my opinion,
adequate redundancy for serious IFR operation. I'm sure that there are many
other good ideas out there, this one works for us.

Bill & Sue
harrelson@erols.com
N5ZQ