Because a GPS failure or outage can affect an entire REGION, while if a
single ground based navaid goes on the fritz, other stuff nearby will
likely still work.

Truth is, right now, the best approach minimums are with ground based
ILS equipment. Unless you have baro-VNAV capability (which is not in the
cheaper GPS equipment) the GPS approach may leave you in the clouds
while the "antiquated" precision approach equipment can get you to 200
feet and a mile.

Get some instrument training.. not the whole rating.. but some.. and see
what is out there. (I am presuming you dont have one, but that is just a
hunch)

Also, if you dont have a rating yet, and plan to train in your own
plane, you will need to be equipped for the checkride to perform 1 type
of precision approach and 2 types of non-precision approaches (unless
things have changed and I missed the memo). Having a "cheap ifr GPS" may
not even have approach capability. Those that currently do are likely
only LNAV (no glideslope, thus non-precision approach). Unless you have
a Precision Approach Radar site, or a VNAV (baro aided or WAAS) you will
need an ILS to meet the checkride requirements in that plane


Dave

tom pettit peak wrote:
So how come I can't just use the gps alone? It seems like it is much more
flexible, and then I wouldn't be as dependent on what ground based stuff was
available.
tom


Basically, what this all boils down to, is this: If you have a
IFR-certified GPS system (TSO-129 certified), like the Garmin
GNS 430, you can use it for IFR operations, but the plane needs
to be equipped with the typical IFR navigation radios anyway.