Originally Posted by
melmothtw
Yep, to add a cargo door basically.
Of course it didn't meet the USAF requirements, which is why they didn't select it. Oh wait...
KC-767 had a cargo door and it did not meet the requirements. No aircraft anywhere met USAF's requirements. Northrop/Airbus's
proposal (as well as Boeing's) met the requirements, but not the existing aircraft. But the bottom line was that neither the A330MRTT nor the KC-767 could meet USAF's requirements. Keep in mind that in 2006 when the RFP was released, Airbus did not even have a single flight qualified refueling boom, while Boeing had two. But Northrop/Airbus's
proposal was superior to Boeing's and thus it won the first competition. To put this in perspective, by the time of the final proposal, Boeing had switched to their "advanced boom" (developed on the KC-10) to overcome Airbus's superior boom envelope (the original boom was based on the KC-135 boom). USAF also required a very robust OBIGGS (tank inerting) suite that neither the A330MRTT nor the KC-767 had and which required development. This resulted in a significant delay when the manifolding was done wrong. Also consider that over 25
miles of wiring were added to the KC-767 to turn it into a KC-46. This wiring accounted for a lot of the delays in the program. I can't get into what all that wiring does, but rest assured that neither the A330MRTT nor the KC-767 includes that wiring nor the systems that wiring services. But I can say that because of those systems, the KC-46 does a LOT more than just pass fuel to other aircraft.