David Megginson wrote in message ...

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)
Engine monitor (i.e. EDM 700)
HSI (slaved)
IFR GPS (non-moving-map, at this price)
Stormscope (or Strikefinder)
TPAS
Wing leveller (or other general single-axis AP)

FWIW, and considering as much as I can from the standpoint of
*safety*, not utility:
(handheld GPS, not mentioned, just inserted from my priorities.
I would not fly IMC in a SE plane with 1 alternator without
it. my personal view based on experience and whattodoofing.)
*wing leveller
*stormscope
*electric AI
*rather put the money elsewhere

This may be skewed by the fact that I've never flown with
an HSI or heard first-hand from someone who liked TPAS. It's
also skewed by the fact that we get some in cockpit wx from
CBAV and are consciously conservative about IMC near tstorms.

We have both an IFR GPS and a four-cylinder engine monitor
and while both of them are indeed very handy and helpful,
I don't personally feel they do much to improve safety in flight.

The engine monitor is helpful when I have a rough mag drop
I can't burn off. L/R tells me top or bottom, the engine
monitor tells me exactly which plug. It warns me of impending
problems sometimes. But in flight if the engine's running rough
it's pretty low on the priority list to stick my head in the
cockpit and scrutinize the engine monitor.

We love our IFR GPS. It gives us a huge amount of utility.
Bang for the buck, it's the most cost-effective nav. equipment
in the plane. But for safety, I don't see it as giving much
that a handheld GPS (esp. with an installed external antenna
and power feed) doesn't provide.

For utility, this is strictly a matter of personal
flight patterns. We fly a lot to small airports where the
choice is GPS or NDB, and we also fly a lot in a region with
decent radar coverage at our altitudes and low enough
traffic that we can be cleared direct.

If we flew a lot out west where we'd have to be on airways
'cuz there's no radar, or if we mostly flew into airports
served by VOR and LOC approaches, AND if we already had
a solid ADF and DME, the IFR GPS wouldn't add as much.

I suppose it could be argued that flying a GPS approach is
significantly safer than an NDB approach flown by God's Gift
to Instrument Flight but I ain't goin' there *g*. I do
have my limits!

BTW, you can certainly get a moving-map IFR GPS installed and
certified within the budget you mention. It won't be the
latest and greatest 430 or 530 unit. It will be an early-generation
IFR GPS slaved to a simple moving map unit or a 2nd/3rd generation
IFR GPS which includes a basic moving map. My CFI just an UPSAT
model installed in his Cheetah for ~4-5K -- hard to tell exactly
as he had other work done at the same time such as installing a
2nd glideslope receiver.

Cheers,
Sydney