Say I enter a flight plan into my GTN750 from A via various WPTs to B. Then I load a procedure, e.g. a GPS approach, into the plan. Do I still need to delete WPT B? In my GNS530 I always need to do that otherwise it takes it as a real WPT instead of just flying the procedure.
Yes.
That’s weird.
Say I am flying EGKA MID EGMD and I load the GPS approach for EGMD. I now have to manually delete EGMD?
In the KLN boxes you don’t need to do that. The approach procedure just gets inserted into the flight plan. What you do need to do however is manually choose the desired IAF and either clean up the flight plan by removing preceeding waypoints, or when somewhere past MID just set a DCT to the IAF. But the Garmin can’t possibly know (for sure) which IAF you wanted to join to.
If I load an approach, the WPT are inserted after that airport WPT. If I do nothing, it wil fly to the airport and then back to the first WPT of that approach. This is how the GNS530 does it. Actually the device should know that the airport is not a WPT because I loaded the approach for it. It denotes it in the flight plan as approach as well. Strange.
Activating “loaded” approach sequence might help ….
You don’t want it to delete the waypoint as you may want to still fly towards the airport. Loading the approach with a particular IAF may be a guess. You do need to be careful of this but I always manually activate by direct to a waypoint in the approach.
But there are also wrong estimated times if I don’t delete it…
Yeah… you get massive errors in the EET and the LFOB. The latter one can be a bit scary until you realise the dogleg in the flight plan 
It’s a bit like when ATC recently gave me a WP which produced an LFOB of minus 1000 gallons… I asked them to spell it again. Usually these things are obvious on a moving map display but sometimes not if you are zoomed in the wrong way. Also some errors are not visible if the overlaying tracks are right on top of each other.
Yes, you have to ACTIVATE the approach … but you don’t delete the airport waypoint, just iike you don’t do that with the 430
Activating the approach is the equivalent of doing directly to the IAF. Not really something I would want to do straight after departure… if you want the approach in the flight plan, deleting the airfield is the best way to go (or not entering it in the first place).
Personally, I only load the approach when I know what it is likely to be and I do the approach briefing.
For en-route fuel planning, I am normally happy with the last leg ending up overhead; I establish a minimum fuel overhead destination as part of planning which includes an approach from that point, the missed approach, and the reserves.
