Presumably it would be a GNS430W, and retaining all the previous analog connections from the old GPS.
If the old GPS was a GNS430, would the GNS430W give you LPV directly i.e. would all the glideslope connections be already “right” for the autopilot?
Yes.
KLNXX—>SN3500—>GPS400W
Only new antenna + cable ( I will be considering this option..)
There is an issue with autopilot coupling and the LPV glideslope. You have to make the LPV GS look like an ILS GS, which requires some bodging of the ILS ENERGISE signal, IIRC. And then you end up with the 2-step procedure to enable LPV GS capture, because the AP (unless it is a GFC700 or DFC90) disconnects when it sees the NAV to GPS mode switch.
I can’t actually put in a GNS430W in place of my KLN94 because (a) there isn’t enough room and (b) the KMD550 is not 100% compatible. But there are some intermediate options, via the SN3500 which drives the AP from its own outputs, so the AP doesn’t know anything about whether the GS comes from ILS or LPV.
KSN770….
Recently, I read that the STC required for LPV approaches in an EASA reg with a GNS430 was 5000 Euros. Can anyone confirm?
You will need an STC for that as it is considerd a major change by EASA. Major changes can only be performed by certified design organisations (DOA). If there is no “wide” STC available, you will need an STC for your specific aircraft, which is quite expensive.
Thanks. That does indeed make the GTN a more sensible proposition if EASA reg.
Best thing obviuosly (as usual) is to avoid EASA reg.
That is why most modern avionics come with an STC for the most populair aircraft. Else it would be very hard to sell that equipement. On the GTN you still need a minor change approval. The minor change approval is to approve the configuration you choose from the STC as the STC is very wide.
If the old GPS was a GNS430, would the GNS430W give you LPV directly i.e. would all the glideslope connections be already “right” for the autopilot?
You most likely will have to add three wires to interface to the KFC225. GPS Select replaces GPS Annunciate and the Arinc 429.