On Mon, 28 May 2007 02:54:04 GMT, Judah wrote:

Ron Rosenfeld wrote in
:

Yeah, but there isn't any regulation allowing substitution of GPS for other
NAVAID's.

I think the AIM revision was just published today on the FAA web site. I
find it pretty confusing in terms of which units are allowed to do what.

But if the AIM is not regulatory, why does it matter?

IIRC, the Regs only say that you must have the equipment necessary for the
specific navigation being used.

The lack of regulatory power of the AIM is one of those arguments that goes
on from time to time. But I believe that, regardless of how we may want to
interpret things, the FAA would have a pretty good case, if they wanted to,
if you, for example, landed out of an approach requiring an ADF, and you
did not even have a functioning ADF on board, nor an FAA approved
equivalent.

If I were the FAA lawyer arguing, I would point out the following:

-------------------------
91.205

a) General. ... no person may operate a powered civil aircraft with a
standard category U.S. airworthiness certificate in any operation described
in paragraphs (b) through (f) of this section unless that aircraft contains
the instruments and equipment specified in those paragraphs (or
FAA-approved equivalents) for that type of operation, and those instruments
and items of equipment are in operable condition.

(d) Instrument flight rules. For IFR flight, the following instruments and
equipment are required:

(2) ... navigational equipment appropriate to the ground facilities to be
used.
------------------------------

It is the AIM that effectively gives the FAA-approved equivalent (specified
in para (a)) for the navigational equipment specified in para (d)(2). And
the AIM specifically requires, for GPS equivalents, that they be compliant
with the AC.

I'm sure someone will write that a GPS that has been specifically listed as
UNapproved for an approach related operation in the AIM can be used for it
because it is somehow "appropriate to the ground facility being used" and
the AIM is not regulatory. I would prefer to be on the other side of that
argument.

Hopefully, the AIM, and possibly the AC, will be changed to again indicated
that previously approved FAA-equivalents are continuing to be approved.
--ron