So I was discussing this with a friend of mine who just bought a 152 that wants to fly it IFR. He wants to buy a DME for it but doesn't want to spend much money. After looking at prices for used King DME's I told him he might as well buy a used King GPS for a little more. This is when we butted heads, he doesn't want to pay the premium for the GPS which I can understand. So my question is can he buy a VFR GPS and use that as the substitute for DME? My other question is will an out of date IFR GPS not be legal to fly under /A? This is all saying we decide to use the GPS as our DME substitute. I believe and correct me if I'm wrong, is it is ok? The airplane is not filed as a /G where GPS is our primary means of navigating. FAR's also do not state whether the GPS has to be an IFR unit to be substituted for DME. Like I said correct me if I'm wrong because I'd rather be wrong then spew out incorrect info. Thanks