A friend has visited a Garmin shop in the USA, specifically asked about the G3X and flying GPS approaches, and sent me this:
So this settles it.
Obviously you could create a lateral profile for any approach using user waypoints, but you could not create the data block required for LPV.
Sorry, that was me, forgot to post here after the red-eye flight home.
The gist of my conversation with the very knowledgeable sales rep in the Garmin shop there was that yes, there are ways for Garmin to make the G3x legal for approaches, but they just aren’t interested because it would take a bunch of money away from the GTN.
The G3x (and Dynon and AFS and MGL and GRT and so on) is an incredibly capable piece of VFR nav kit, and combined with an IFR GPS device it has some amazing functionality as an IFR PFD – far in advance of anything in the certified market, at a miniscule fraction of the cost of the certified kit.
Regarding the posting above that Greece accepts homebuilts for IFR:
I have just received this from a Greek airport manager (known to me personally):
For experimentals they follow the respective EASA regulation, and when ramp-checking they check that it has a Permit to Fly (PtF – http://easa.europa.eu/easa-and-you/aircraft-products/permit-fly.
This is as expected i.e. if the permit says “VFR only” then it is VFR only. Which ECAC Permits allow IFR on the Permit? N-reg obviously does but then you get other issues.
There does not appear to be any Greek law on the subject, so I wonder what would happen if somebody just parked an N-reg homebuilt somewhere in Greece? Quite possibly nothing.
Peter wrote:
Which ECAC Permits allow IFR on the Permit?
It doesn’t work like that. That is a wrong question asked. In Norway (and I guess Sweden, France, Poland etc etc), a Permit is only issued during the test phase for a limited period, one year at a time, and is VFR day only. When the test phase is done, the aircraft receives a restricted C of A. The restriction being non-commercial operation only, and maybe some other stuff but I don’t know what. But, as I have learned a month ago, there will be nothing about VFR vs IFR vs NVFR, the CAA doesn’t care (literally), and they have made this very clear in an AIC. To fly IFR, you simply go to a shop and install the needed avionics, systems and instruments, that’s it.
To the best of my knowledge, in Poland you can get an “special” certificate (or permit, I am not sure on the distinction, nor what piece of paper one actually gets) which allows IFR flight, provided certain equipment and design prerequisites are met (e.g. instruments, an engine certified for IFR flight, etc). This is applicable ONLY to planes that DO NOT have a CoA. The downside is that piece of paper is really valid only in Poland, flying abroad is based on either treaties or getting permission. So it’s not much use for trouble free IFR flight anywhere one wants to fly on a whim.
So yes, one could probably get a RV with an IFR permit/special certificate in Poland, but it still doesn’t match the usefulness of a plane with a regular IFR certificate.
edit: changed “experimental” to “special” to better reflect the category name
Interesting article on RV safety
Looks like Vans made a similar experience as Cirrus did in the beginning.
Some incredible performance :
https://vansairforce.net/community/showthread.php?t=196589
An RV9 with an IO360 and electronic ignition (variable timing) doing 742nm in 5 hours, with 950nm to spare !!
(At 17500ft, 145KTAS, burning mogas)
It could do Shoreham-Kithira. Peter’s ideal plane 
That is impressive, here is a fresh 2021 edition, non certfied IFR at 0.5m$ !
LOL
The one I referred to is a 2-seater, side by side.
