GPS for NDB IAF on ILS?

I don't have my AIM here at work, and I'm on dial up, so I won't attempt to
download it, but I'm looking at the ILS 32 into KMQY Smyrna TN. It says ADF
REQUIRED which I understand is to identify the IAF which is the SWZ NDB not
associated with a marker beacon, inside the outer marker. This is the only
IAF charted, it is also the missed approach holding location.

My question is: In this situation is it legal to use a IFR Term Certified
GPS to substitute for an ADF.

Thanks
Jim

Jim Burns wrote:

My question is: In this situation is it legal to use a IFR Term Certified
GPS to substitute for an ADF.

In the US, my understanding is yes, the GPS is legal to use as a substitute
in this case. See the AIM 1-1-19, subsection F (Use of GPS in lieu of ADF
and DME)


--
Peter













----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Yes. The only time you can't use it is to substitute for an ADF on an
NDB approach.





Jim Burns wrote:

I don't have my AIM here at work, and I'm on dial up, so I won't attempt to
download it, but I'm looking at the ILS 32 into KMQY Smyrna TN. It says ADF
REQUIRED which I understand is to identify the IAF which is the SWZ NDB not
associated with a marker beacon, inside the outer marker. This is the only
IAF charted, it is also the missed approach holding location.

My question is: In this situation is it legal to use a IFR Term Certified
GPS to substitute for an ADF.

Thanks
Jim

The only time you can't use [GPS] is to substitute for an ADF on an NDB approach.

Any idea why that is?

Jose
--
Nothing is more powerful than a commercial interest.
for Email, make the obvious change in the address.

Newps wrote:

Yes. The only time you can't use it is to substitute for an ADF on an
NDB approach.

Unless there is a GPS overlay for the NDB approach?

OK, you're right. That wouldn't technically be considered substitution.

--
Peter













----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

In article ,
Jose wrote:

The only time you can't use [GPS] is to substitute for an ADF on an NDB
approach.

Any idea why that is?

Jose

Because the FAA has a bad case of recto-cranial inversion?

Thanks. Just got home and that was my interpretation of the AIM. As for
Jose's question, Newps answer concerns an NDB only approach, not a NDB GPS
overlay, and the reason being is that because in an NDB only approach you
must have the proper radios for the approach. If it only says NDB in the
approach title, you need an ADF receiver to fly the approach. You may
already know that, if so, sorry for beating it to death.

The AIM ref is:

(f) Charted requirements for ADF and or DME can be met using the GPS system,
except for use as the principal instrument approach navigation system.

Beyond that, one reason may be that a NDB only approach hasn't been blessed
by the FAA and converted to an NDB / GPS or an overlay.
Or, they may have a separate GPS approach. There are several near me that
they've not chosen to do an overlay, but instead created a separate GPS only
approach that aligns you better with the runway.

Other reasons I'll leave up to the rest of the group.

Jim

Jose wrote:

The only time you can't use [GPS] is to substitute for an ADF on an NDB approach.

Any idea why that is?

Every NDB approach in the country was authorized as a GPS overlay approach when the
overlay program came into being. Since then, these authorizations have been withdrawn
for any particular runway end when a stand-alone RNAV (GPS) approach was published for
that runway end.

You cannot use GPS for any final approach segment that is not retreivable from the
database, and for good reason: no approach RAIM and no approach sensitivity.

It's stupid. I can fly an NDB approach with a GPS and it's an easy
thing to do.

Jose wrote:
The only time you can't use [GPS] is to substitute for an ADF on an
NDB approach.


Any idea why that is?

Jose

Peter R. wrote:

Newps wrote:


Yes. The only time you can't use it is to substitute for an ADF on an
NDB approach.


Unless there is a GPS overlay for the NDB approach?

OK, you're right. That wouldn't technically be considered substitution.

He didn't have an approach box.