Also, I've just been reading some stuff on GPS/AP integration for LPV approaches, and it does get a bit tacky because the GPS has to fake an ILS glideslope for the benefit of the AP, etc. Maybe integrated avionics (with an integrated AP, which means Garmin unless Avidyne get their act together) will be the norm by the time we get them and they are operationally relevant.
Not sure of the terminology, but once that's achieved would one have in effect a mini-Airbus where you could switch AP on after take-off and only re-take manual control below decision height on the approach? Or could you even auto-land
