When can RNAV equipment be used as a substitute means of navigation guidance? (AIM 1-2-3)
a) Determine aircraft position over or distance from a VOR, TACAN, NDB, compass locator, DME fix; or a named fix defined by a VOR radial, TACAN course, NDB bearing, or compass locator bearing intersecting a VOR or localizer course,
b) Navigate to or from a VOR, TACAN, NDB, or compass locator,
c) Hold over a VOR, TACAN, NDB, compass locator, or DME fix,
d) Fly an arc based upon DME
[Note: these operations allowable even when a facility is explicitly identified as required on a procedure (e.g., "Note ADF required"). Also, these operations do not include navigation on localizer-based courses.