Please forgive my brief and sporadic posts, but I wanted to clarify something that has been incorrectly addressed on several recent tanker related threads.
By the way, I am a newbie here - and not this Keesje fellow some of you suspect that I am!
The cargo door for the KC-330 will be virtually identical in function and dimensions to the ones flying on freighter versions of the A300 and A310 for nearly a decade. With the exact same fuselage cross section as those shorter birds, engineering and certifying (from the FAA perspective) the big door on the KC-330 is relatively simple.
Also, some of you may be surprised to know that the KC-330 will use the existing fuel storage system of the civilian A330-200 - without additional tanks anywhere - thereby preserving all cargo space above the main deck and the fore and aft holds below deck. Provided you don't max out your take off weight carrying nothing but a massive load of fuel - which you can do if you have to - you have incredible mission versatility!
Another nice design element is that since the commercial A330/340 family share the same wing design with 4 wet engine hardpoints, the hose and drogue pods "bolt on" where the outboard engines would go the the A340, without requiring all of the engineering rework and minor performance penalties the KC-767 takes to carry the pods.