Hello,
Just as an intellectual game (just after PBN course), I looked into WAAS upgrade, for a non-WAAS G1000 C182.
As you may know, there is a SB released by Cessna, with a Modification Kit, to perform the upgrade. It costs several tens thousand of dollars – just mad. Maybe the parts will be less expensive some day, and upgrade will be more easily feasible.
The only good point is that upgrade is rather easy: just swap two GIA63 from the avionics bay for two GIA63W, and change the two COM/GPS antennas. Upgrade the software, and you’re done. Much easier than Peter’s next winter 
My questions was about AP coupling.
Without WAAS, the KAP140 is able to couple in NAV mode with any NAV/GPS signal (lateral).
In APPR mode, it will follow an ILS, LOC and GLIDE (lateral and vertical).
After WAAS upgrade, you will be able to perform LPV approaches.
Here and there on internet, some people claim that the KAP140 will have horizontal and vertical coupling for LPV, as LPV generates the same kind of vertical signal as an ILS glide slope.
However, in a revision from the initial SB, Cessna states this:
The Honeywell KAP-140 autopilot, if installed and operational, will couple and track the lateral guidance provided by the SBAS navigational guidance. However, the vertical component of any GPS approach must be managed and flown by the pilot. The KAP-140 autopilot WILL NOT couple to GPS vertical guidance.
Would be interesting to read your opinion about this !
https://aviation-safety.net/wikibase/wiki.php?id=215989
https://www.rheinpfalz.de/lokal/artikel/flugplatz-speyer-flugzeug-faengt-feuer/
It can happen at any time, regardless if you’re flying or not.
