To help everyone in this discussion avoid jumping to absolutes (I'm
not accusing you of that, by the way), here's a different way to
approach the problem. Let's say you have a basic plane like mine -- a
125 kt, 160 hp, fixed-gear Warrior II with dual NAVCOM, DME, and ADF
-- that you fly a few hours each month in actual IMC and the rest in
VMC or marginal VMC (filed IFR, in that case).

I think given the class of airplane, you really need to consider trading up to a
more capable airplane before installing some of the items on the list. You'll
end up with way more money invested in your upgrades than you can recoup on
resale for this kind of airplane. Besides, you'll find it's less expensive to
let someone else install this stuff. Buy an airplane with the equipment you want
already installed, to the extent possible. But OK, I'll accept your premise
anyway, and comment on your list


You decide that you can afford to install *one* new permanent system
costing from USD 4K to USD 10K this year, and possibly one in each
following year (but not for certain). Arrange the following list in
the order that *you* think would make your IFR flying safest, putting
the highest priority item at the top. If you want, you can assume
that you already have some kind of backup vacuum system. These are
currently in alphabetical order:

Electric AI (backup)

Go with the dual-rotor vacuum pump from http://www.aeroadvantage.com instead.
There just isn't a quality electric AI on the market that's in the price range
of what you'd want in a piston single. They are either way too expensive, or
they just don't work very well. Apologies if everyone is getting tired of me
pushing this dual-rotor pump, I've posted about it several times. I just think
it's a great price performer and gives a lot of redundancy for the money.

Engine monitor (i.e. EDM 700)

Nice to have, but not a necessity in this class of airplane. Get one when you
move up to a big-displacement six.

HSI (slaved)

Nice to have, but too expensive to put in this class of airplane.

IFR GPS (non-moving-map, at this price)

Yes. I might even spring for the moving map. Garmin 430 is still the sweet spot
in this market, IMO, for this class of airplane.

Stormscope (or Strikefinder)

Very useful if you're doing summer cross countries, at least in the middle
atlantic states where I fly most. Adds a lot of capability to the airplane, IMO.
Marginal whether you want to move up to more of a travelling airplane first,
rather than put this money into a basic IFR trainer.

TPAS

I think the mode-S transponder with the Garmin 430 might be justifiable in this
airplane, especially if you're getting the 430 anyway, and have to replace the
transponder for some reason.

Wing leveller (or other general single-axis AP)

Yes, useful. Consider getting one that's independent of vacuum.

Remove SHIRT to reply directly.

Dave