IFR use of handheld GPS

In article ,
Matt Whiting wrote:

So if the AIM says that handhelds are not authorized for IFR
navigation, there must be a rule somewhere, right?

Not necessarily. The AIM is meant to contain information that is "good
practice", not just regulatory information. The FARs are for
regulation. If the AIM was also regulatory and only contained
information already in the FARs, what would be the point of it?

Yes, it's true that the AIM is "not regulatory". We all learned that and
regurgitated it back on some private pilot knowledge test long ago. But,
just because it doesn't cite chapter and verse from 14 CFR is no reason to
completely ignore what it says.

The paragraph in question is 1-1-19-d-1-(a):

1. Authorization to conduct any GPS operation under IFR requires that:

(a) GPS navigation equipment used must be approved in accordance with the
requirements specified in Technical Standard Order (TSO) TSO-C129, or
equivalent, and the installation must be done in accordance with Advisory
Circular AC 20-138, Airworthiness Approval of Global Positioning System (GPS)
Navigation Equipment for Use as a VFR and IFR Supplemental Navigation System,
or Advisory Circular AC 20-130A, Airworthiness Approval of Navigation or
Flight Management Systems Integrating Multiple Navigation Sensors, or
equivalent. Equipment approved in accordance with TSO-C115a does not meet the
requirements of TSO-C129. Visual flight rules (VFR) and hand-held GPS systems
are not authorized for IFR navigation, instrument approaches, or as a
principal instrument flight reference. During IFR operations they may be
considered only an aid to situational awareness.

While the AIM may not be regulatory, it also doesn't lie. When a simple
declaratory statement is made such as, "hand-held GPS systems are not
authorized for IFR navigation, instrument approaches, or as a principal
instrument flight reference", it's a pretty good guess that there is some
regulation, somewhere that backs that up. Anybody who feels confident
enough that handheld GPS is good enough for IFR is welcome to invite an
FSDO guy to ride along with you for an inspection with a handheld as your
sole means of IFR navigation outside of DR, vectors, celestial, and a ham
sandwich. See how far you get. Then please post about it so we can all
share in your experience.

Until that time, all this talk about how the AIM is not regulatory and how
it's OK to fly IFR with a handheld is just a lot of masturbation.