Ibra wrote:
You can have glide path to fly on NAV+VPATH to any waypoint as long as you input WPT & Select target Baro AMSL altitude but your VNAV & LNAV will run in ENR mode (+/-5nm and higher HPL/VPL with no internal accuracy checks)
Minor points, Enroute is RNAV 2 and FSD is +/- 2 NM. VNV or VPATH is baro.
NCYankee wrote:
Minor points, Enroute is RNAV 2 and FSD is +/- 2 NM. VNV or VPATH is baro
You are (again) right GPS CDI on ENR is always set to +/-2nm (even if airspace is still RNAV5 
)
Yes, VNV or VPATH is from one baro altitude to another baro altitude but how do you fly between if you don’t have Baro-VNAV inputs? my guess the calculated TOD/PIT/ROD in your navigator comes for GPS position & altitude and depends on quality of it’s signal?
In other words, the derivative or guidance use bit of GPS while the final or target state is pure BARO
NCYankee wrote:
Minor points, Enroute is RNAV 2 and FSD is +/- 2 NM. VNV or VPATH is baro
You are (again) right GPS CDI on ENR is always set to +/-2nm (even if airspace is still RNAV5 )
Yes, VNV or VPATH is from one baro altitude to another baro altitude but unless you have Baro-VNAV inputs the calculated TOD/PIT/ROD your navigator will fly rely on GPS position & altitude as well as it’s quality of signal? derivative or guidance comes from GPS while the final or target state is BARO
Ibra wrote:
ou are (again) right GPS CDI on ENR is always set to +/-2nm (even if airspace is still RNAV5 )
Yes, on an SBAS box such as the GNSx30W. On a non-SBAS box its +/- 5 NM. (I really don’t see why as non-SBAS boxes are perfectly capable of RNAV 1 and RNAV APCH.)
Airborne_Again wrote:
Yes, on an SBAS box such as the GNSx30W. On a non-SBAS box its +/- 5 NM. (I really don’t see why as non-SBAS boxes are perfectly capable of RNAV 1 and RNAV APCH.)
Me now thinking is all boxes capable of VNAV are SBAS? 
Ibra wrote:
Me now thinking is all boxes capable of VNAV are SBAS?
LNAV/VNAV, yes. “Enroute” VNAV – I don’t think so. At least I see no reason why.
all boxes capable of VNAV are SBAS?
That statement is probably true in reality, simply because every IFR box out since the GNS430W (2005?) has been SBAS capable.
They had G1000 no WAAS just shortly after but aircraft had interfaces for KAP140, so no way to see ENR VNAV in FD/AP even if it was something in the navigator?
There should be a reason why Garmin never had ENR VNAV (or even LNAV+V) in non-SBAS boxes? maybe it was not stable or performing well? or they wanted that built with their AP (GFC700/500)?
G1000 no WAAS
Yes very true; a load of DA42s have this very problem!
Out of interest, how is autopilot driven VNAV implemented? Does it use VS mode with an altitude preset and fake the VS selection button input, or does it use ILS mode and fake a GS input?
It’s fake GS, the dot is given by actual aircraft baro altitude against desired baro altitude, the latter desired baro uses GPS position & GPS altitude data (this should work for non-SBAS box but maybe it was not very smooth for KAP140 GS mode to hook on it?)
