Originally Posted by
DaveReidUK
Now you've lost me completely, I'm afraid.
If we agree that the 4,500 A320s built to date had their wing correctly positioned(!),
That's not a necessarily true assumption... at least in the sense that there are no CG problems. Such problems are common.
For example, the CRJ 200 at full or nearly full loads is often outside the forward limit, requiring the movement of passengers backwards. If it's totally full so that no one can move, then you have to add ballast. Now if a 190 pounds jumpseater wants to get on, he's really a 400+ pound weight addition.
So it's hard to see how there would be any specific aerodynamic advantages resulting from putting an A320 cargo door aft, rather than forward of the wing.
Do you see it now? If you're more commonly bumping against one end of the allowable range, and you're about to add weight, naturally it's better to add it closer to the other end.