Originally Posted by
stilton
Why does the A330 MRTT not have a main deck cargo door ?
Some do. Most don't. That's up to the customer. But keep in mind that every A330MRTT starts out as a regular airliner. After the airliner is built it gets flown to a modification center where it is taken apart to convert it into a tanker. Adding a main deck cargo door adds more cost. Adding a main deck cargo floor adds even more cost. If you only want a tanker that can also haul passengers on occasion why pay all that extra money?
So why do USAF tankers
all have cargo doors and floors? USAF routinely uses their tankers as freighters. The tankers (along with C-130s, C-5s, C-17s, etc) are all in Air Mobility Command and are part of USAF's airlift fleet . Remember that most European and Asian militaries are garrison forces. That is they are not designed to deploy regionally, much less globally. Most of the US military are global expeditionary forces. They are almost all designed to deploy globally. That even includes the Army's and USMC's heavy armored divisions. On the rare occasions that non US military units deploy, they are heavily dependent on US and Russian (yes, Russian) airlift. By making every tanker also a freighter, USAF can use the tankers as freighters to get the forces into the theater, and then in theater use the same airframes as tankers to provide tanking support.
In short the answer to the question is cuz most A330MRTT customers use their tankers almost exclusively as tankers and don't need (or want to pay for) an outsize freighter capability.
BTW even with all their organic airlift capability (C-130, C-5, C-17, KC-135, KC-10, KC-46, etc), USAF still does not have sufficient airlift. That's why they also have CRAF. CRAF (Civil Reserve Air Fleet) is a program that assists major US airlines to buy commercial freighters, gives those airlines preferential access to US military cargo in peacetime, and more recently, provides access to military facilities to operate commercial freighter business. In return, the airlines commit those airframes and crews to provide DoD airlift in the event CRAF is activated in wartime. (CRAF is activated in three stages.) The first CRAF activation was in August 1990 in support of Desert Shield/Desert Storm.