GPS for ADF

[Greg]

When can GPS substitute for ADF?
What about an ILS with note: "ADF REQUIRED"? (for missed approach)
thanks,
Greg

[rps]

Greg wrote:
> When can GPS substitute for ADF?
> What about an ILS with note: "ADF REQUIRED"? (for missed approach)
> thanks,
> Greg

Search this newsgroup for related postings over the last 6 months. The
topic has been discussed extensively.

[Ron Rosenfeld]

On 13 Jun 2006 20:21:31 -0700, wrote:

>
>
>It looks OK because that is a special equipment note, not the approach
>type.
>
>In the following article at the end it states
>
>"You can use GPS in lieu of ADF on an ILS, for a stepdown fix or when
>ADF is required in a special equipment note. The only exception is
>this: If you don't have ADF aboard, you can't use GPS to fly an NDB
>approach that isn't overlayed. In other words, no ADF, no NDB approach,
>unless it's also an overlay."
>
>http://www.asy.faa.gov/safety_products/GPSSafetyAdv.htm
>
>Of course we talking a IFR-GPS w/ current database,etc,
>
>Does anyone know the actual FAA regulation on this?
>
>
>
>Greg wrote:
>> When can GPS substitute for ADF?
>> What about an ILS with note: "ADF REQUIRED"? (for missed approach)
>> thanks,
>> Greg


That article is old and (2003) and has been superseded by more recent
publications. Probably the best information is in the AIM.

In general, you can use an IFR GPS to substitute for ADF (or other
NAVAIDS). so long as the fix is in the database, and the facility is not
being used to provide "primary" guidance for the approach.

All of the overlay approaches have been renamed to include GPS or RNAV in
the title.

Whether or not a receiver for the underlying NAVAID is required generally
depends on the certification of the GPS (TSO129 vs TSO146 and variations).

So you can use GPS to substitute for ADF in the instance cited (so long as
the ADF fix is in the Database), but you could not use it as a substitute
for a procedure labelled as Kxyz NDB Rwy 15 approach.

Similar requirements for DME substitution, although the only approach I
know of that uses DME as the primary navaid is the KMTN VOR DME Rwy 15
approach.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[Sam Spade]

Ron Rosenfeld wrote:


> All of the overlay approaches have been renamed to include GPS or RNAV in
> the title.
>

Do you have an example of an overlay that states "...or RNAV" instead of
"...or GPS?"

[Ron Rosenfeld]

On Wed, 14 Jun 2006 12:27:19 -0700, Sam Spade > wrote:

>Ron Rosenfeld wrote:
>
>
>> All of the overlay approaches have been renamed to include GPS or RNAV in
>> the title.
>>
>
>Do you have an example of an overlay that states "...or RNAV" instead of
>"...or GPS?"

No, I don't. Do you?
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)