GPS vs ADF

I'm still a little confused how I'm expected to legally fly an ILS approach that
uses a NDB as its IAF with a GPS on board instead of an ADF. (For example, the
ILS Runway 2 approach into KUZA (Rock Hill, SC)). The rental aircraft I have
access to these days all come with GPS, which is very nice, but I still want my
ADF for the little airports I sometimes fly into.

Feel free to educate me... I was out of flying for 15 years and the technology
passed me by. The last time I was flying regularly LORAN was just coming to
aircraft, and everybody was flying ILS, NDB, and VOR approaches. I took an IPC
to get my instrument currency up to date but we used the older equipment with
which I was already familiar. I'm comfortable enough setting up a Garmin 430 to
navigate to another airport but that's about the limits of what I can do with
one. Don't have a clue about GPS approaches....

Some people refer to IFR GPS as "flexible," meaning it can do many
different things. Some refer to is as "a frustrating piece of crap,"
because they find it so hard to make it do any one particular thing. I
find that the user interfaces on GPS units are very intuitive and
obvious - as long as you have a graduate degree in engineering and
several years experience working with computerized instrumentation.
Describing IFR GPS as flexible is a lot like saying a drowning victim
has moist skin. It's technically true, but you're not impressed.

There are lots of ways to accomplish what you want - that is, to use an
IFR GPS instead of an ADF to fly an ILS approach where the IAF and MAP
is a LOM. If you're used to doing it the old fashioned way, then the
method that will make sense to you will be the one that all the people
who actually like and understand IFR GPS will consider the least
desirable (and it's one I probably would not use myself unless I was
unfamiliar with the available GPS). Here goes:

Use exactly the keystrokes you would use to make the IFR GPS point to
the airport (meaning the direct-to function). However, instead of
dialing in KUZA for the airport, dial in RALLY (the intersection that
marks the LOM).

To fly the approach:

Go direct to RALLY as you would to an airport. When the distance from
RALLY reads close to zero (say less than 0.5 nm) turn outbound and
track the LOC outbound, and when ready perform the PT. Proceed as with
a normal ILS. The GPS will probably give you numeric absolute bearing
to RALLY just as an ADF would, only better, and also distance to RALLY.

To fly the missed approach:

Upon starting your climbing turn to the left, do the same direct-to you
did before (you should not need to dial in RALLY again, so probably
just direct-to and enter or the equivalent - two keystrokes - will be
required) and fly direct to RALLY. Make the teardrop entry as normal,
and use the LOC for guidance on the inbound leg.

There are other ways to do this. Many other ways. IFR GPS is very
flexible and powerful. With a 430, you can get a diagram of the
approach to come up, get guidance to the IAF, lines to follow for your
PT, and automatic switching to LOC mode when established inbound as
well as automatic sequencing for the missed approach with a visual
depiction of the hold and prompting for the correct entry. But the
basic method I gave you will always work with any GPS, and will seem
natural to someone who is used to flying steam gauges.

Michael