Thomas Borchert ) wrote:

Is it allowed to use an IFR-approach-certified GPS instead of a DME in
a LOC-DME or VOR-DME approach that does not have a GPS-overlay?

YEs. See AIM 1-1-19. Global Positioning System (GPS), subsection (f).

http://www.faa.gov/ATPubs/AIM/Chap1/aim0101.html#1-1-19

A quote:

--- quote ---

(f) Use of GPS in lieu of ADF and DME

1. Subject to the restrictions below, operators in the U.S. NAS are
authorized to use GPS equipment certified for IFR operations in place of
ADF and/or DME equipment for en route and terminal operations. For some
operations there is no requirement for the aircraft to be equipped with
an ADF or DME receiver, see subparagraphs f6(g) and (h) below. The
ground-based NDB or DME facility may be temporarily out of service
during these operations. Charting will not change to support these
operations.

---- end quote ---

--
Peter