I didn't change anything and I didn't call GSX
That's the issue. If you used GSX to go there with the "Warp me here" menu option, it wouldn't allowed you to select it, because it's a parking too small for an airliner. But the simulator itself doesn't check this, and will let you park everywhere.
From sim starting location was Gate A 223 RAMP GA LARGE so, I guess is for a large plane as 777 or 747 right?
Ok, I see your confusion. In order to prevent the simulator to create its own ground vehicles that can easily conflict with GSX and other details around the apron, we labeled all parkings as GA.
But if you use the GSX menu, with the "Warp me here" function, you'll see all parkings listed with their real life names (the simulator naming convention is too limited to represent JFK), and it will tell you which ones are suitable for your airplane.
I can't find the name of AFCAD from GSX but my airport scanner found files appr_KJFK.bgl and KJFK_FSDT.bgl What do say?
That's correct. But you still shouldn't park there with a large airliner.