Can GPS be used in place of DME for IFR?
Yes, with only a few exceptions. You can use GPS in place of DME if the named fix appears in the GPS database or the datum upon which the fix is based is in the GPS database. For example, if you were flying a VOR-DME approach without a DME in the aircraft, the GPS can substitute if the required fixes are named and included in the GPS database or the VOR upon which the approach is based can be found in the GPS database. One other exception is when flying an ILS-DME, one cannot legally use GPS in place of DME because DME fixes are not normally named in the GPS database. In addition, DME fixes are based on localizer DME sources that do not appear in GPS databases. The exception is ILS-DME approaches that may either have 5-letter named fixes or DME sources based on named datum such as a VOR.
Yes and no. You can use GPS in place of DME if the fix appears in the GPS database For instance, if you were flying a VOR-DME approach without a DME in the aircraft, the GPS can be substituted if the required fixes are named and included in the GPS database or the VOR upon which the approach is based can be found in the GPS database. Remember DME is slant distance. If not taken into account in the database, it’s not the same as GPS distance.