Posted for larry.eversmeyer@faa.gov:

If you buy an IFR certified GPS, you can use this in lue of ADF, DME,
OUTERMARKERS, AND IDENTIFACATION OF INTERSECTIONS WITHIN THE TERMINAL AREA.
You can use it for the DME requirements above flight level 240.

[ may a TSO-C129 A2 (enroute terminal) gps be used lue of ADF, DME
on an approch or do we need A1 (enroute terminal approach) GPS? http://www.rduafss.faa.gov/navaids/gps.htm  -Rob@Logan.com ]