With TSO C145/146 (WAAS) avionics, if WAAS (SBS) is not available, FDE negates the need for a RAIM check, at least in FAA-dom.
Folks,
Does this post from aterpster not really define the situation.
You must know the certified capabilities of what you have on board, and its operational limitations.
I can well imagine that some authorities have a pre-flight planning requirement related to RAIM predictions, but RAIM is not applicable to later generation GPS receivers. If you have C-129 based equipment RAIM is applicable in flight. This is so, whether or not you have WAAS/SBAS for a particular area, WITH c-145/146 BASED EQUIPMENT, all WAAS/SBAS availability does is change the minima.