"Brien K. Meehan" wrote:

Whoever told you it's an indirect regulartory issue was making it up.

Well, okay, but I work with this stuff all the time.

Here is from the current FAA Order 8260.19C:

l. Dual Minimums. Enter dual minimums, when authorized. Do not publish
dual minimums unless a 60-foot operational advantage is obtained or a
reduction in visibility can be achieved. To avoid proliferation of dual
minimums, *all IFR aircraft are assumed to have at least one VOR
receiver*. Dual minimums based on a stepdown fix combined with local and
remote altimeter settings could result in four sets of minimums. When two
remote sources are used, treat the source resulting in lower minimums as
the "LOCAL" altimeter setting source in the following paragraphs.
Document only two sets of minimums. The combinations authorized are
minimums with and without a stepdown fix; or minimums with local and
remote altimeter settings.

The words between the asteriks are reflective of FAA Class I navigation
policy, which is a requirement to be a part of ICAO.

And, from the FAA's Instrument Procedures Hanbook (available in Summit's
Aviation Reference Library):

In the broad concept of air navigation, there are two major categories
of navigational operations consisting of Class I navigation and Class II
navigation. Class I navigation is any en route flight operation conducted
in controlled or uncontrolled airspace that is entirely within
operational service volumes of ICAO standard NAVAIDs (VOR, VOR/DME, NDB).
Class II navigation is any en route operation that is not categorized as
Class I navigation and includes any operation or portion of an operation
that takes place outside the operational service volumes of ICAO standard
NAVAIDs. For example, your aircraft equipped only with VORs conducts
Class II navigation when your flight operates in an area outside the
operational service volumes of federal VORs/DMEs. Class II navigation
does not automatically require the use of long-range, specialized
navigational systems if special navigational techniques are used to
supplement conventional NAVAIDs. Class II navigation includes
transoceanic operations and operations in desolate and remote land areas
such as the Arctic. The primary types of specialized navigational systems
approved for Class II operations include inertial navigation system
(INS), OMEGA, Doppler, and global positioning system (GPS). Figure 4-15
provides several examples of Class I and II navigation.