Ron Gordon wrote:

Ron, I have been flying a lot of IFR in a Bonanza equipped with the GNS430
and GPSS over the last two years in the very busy Northeast US airspaces
(including many flights into Boston, Teterboro, and Philadelphia) and will
be upgrading my unit to the WAAS model sometime this spring. I do not have
any experience at all with the GNS480.

The only two points I would toss in here a

7. With a GPSS the GNS 480 can fly the aircraft through all approach
procedures, including DME arcs, holds, procedure turns, etc.

After playing with the GNS430W simulator I am fairly confident that the
GNS430W coupled with GPSS will also fly published holds/procedure turns/DME
arcs, etc. However, I don't see the GPS430W doing ad-hoc holds, at least
based on my work with the sim.

10. For IFR navigation, the GNS 480 appears to provide more assistance and
more capabilities than the GNS 430W. Perhaps this is what people mean when
they say that the GNS 480 is more FMS-like than the GNS 430W.

I find the GNS430 a very capable unit for IFR flight. While the airways
feature would make life easier, the lack of this feature does not mean the
unit is any less capable than the GNS480, just a touch more tedious. Same
goes for the lack of ad-hoc holds.

Additionally, I have never experienced a GPS failure over about 600 hours
of IFR flight using the GNS430. Can't speak for the GNS480, but in over
500 hours using a Bendix/King KLN94, I experienced three different GPS
"crashes" during flight, with two occurring during approaches. (The B/K
experience thrown in here only as an example of a GPS crash.)

Ultimately I believe the issue between the two units boils down to this:
There have been many in this group who have speculated that Garmin bought
the GNS480 from UPSAT to a) capture working WAAS experience and talent and
b) corner the market of GPS WAAS. Some have concluded, therefore, that
Garmin will abandon the GNS480 unit for the GNS43x/53x line, once these
models are fully WAAS-capable, given the popularity of these models.

As a pilot who has already been burned twice by installing new avionics
that are now being left behind (a WSI weather receiver and a Mode-S
transponder for traffic), I am once bitten, twice shy when it comes to
current avionics models that may also be left behind.

It already seems as if you have done some excellent research. The problem
you will have is having a GNS430W pilot add his/her experience to this
thread, since the units are just starting to trickle out now. Please post
a follow-up here, as I know I would be interested in reading your
experiences in whatever you install.

--
Peter