That’s why I switched off crossfill in my #1 GNS430. Of course you really have to know WHICH waypoint you use for DME.
As I said, the other reason why it’s not critical in the Cirrus is that you have an active approach chart and see exactly where in the approach you are.
I only fly ILS and RNAV/GPS approaches, for now anyway.
Why does one have to disable crossfill?
Is that issue also applicable to the IFD540?
If I have an active Flightplan on # 1 and have crossfill ON then I have the same FPL on # 2. But I need # 2 to enter a “DME”-Waypoint as a Direct!
I would say it should be the same with 2 IFD540s
This is how I do it. I use GPS 2 (on the left of the PFD) as “DME”. Note the (green) aircraft symbol intercepting the final course of the ILS on the MFD
The GPS overlays are probably the Jeppesen way of solving the whole issue – despite the legal part of it. Unfortunately I don’t have an active subscription for Europe yet and can’t see what is being offered outside Germany. From last year I do remember that there wasn’t really a need to be concerned with the DME – although the SR22 I used had a physical DME. That aircraft has an Avidyne R9 – similar to Garmin G1000 – but the DME was not integrated. It was mounted at the last position in the center console and one would have to look down to read it. On the other hand most flights were from VFR airports with a few ILS here and there. The only non-precision approach was an RNAV into EDDK. So I’m not really sure about other types of approaches – hence my original question.
I wish legal and safe would be the same more frequently.
With crossfill, both GNSx30 share the same route and the next waypoint. So if you use GPS1 with the approach loaded (and the missed approach!) for lateral navigation, and you really want the threshold distance on GPS2, you have to switch off crossfill.
Crossfill is a bit like North-Up vs. Track up. It really divides pilots into two camps.
I can’t stand crossfill. Makes me feel like reducing my gear from two GPS units down to one. And please don’t come up with "if GPS1 fails, then I still have my route in GPS2… 
Crossfill is a bit like North-Up vs. Track up. It really divides pilots into two camps.
Yes, those who are right (track up) and the rest. I disable crossfill on a 430W install. Why have 2 GPS if you want to treat them as one?
Well, at least we agree on one out of two points. 
This is a non issue in the US as the DME distance is the distance to the antenna and there are named waypoints for the vast majority of DME fixes. About the only DME fixes that will be missing in the database will be if there is a fix inside the FAF on the ILS used for the localizer version of the approach. These will not show in the database. Also, unless you need better than category I ILS, the RNAV procedures are all based on GPS. What is an ILS? Does it stand for I’m Lost Somewhere?
