Greg Esres wrote:

Garmin is correct. You don't need approach RAIM or approach
sensitivity until the beginning of a final approach segment

I was sure they were, but I'm concerned about how to demonstrate this
correctness to others. The AIM says nothing about this.

I accept that flying the localizer outbound for the PT does not
require approach sensitivity and that the protected area is wide on
the initial segment, but I shouldn't have to know these things in
order to know what I can do with this box.

I'm mostly concerned with checkrides. Is there anything other than
Garmin documentation that can demonstrate this is a legal thing to do?

" non-overlay VOR approach?" True, it could, but the vendors
haven't seen that as a real-world issue.

I haven't done this in the real airplane, but on the simulator, the
box will advise changing to Vloc once established on the inbound
course of a VOR, but will not switch over. In fact, it goes down to
approach sensitivity, but doesn't indicate approach RAIM.

Would you argue that using the GPS for course guidance up to this
point is legal?

If you can retrieve it from a current database with an IFR
approach-approved GPS, it is legal to use. You will note the warning
message Garmin provides when you pull up and ILS approach.