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That article is old and (2003) and has been superseded by more recent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)