The tanker is sent into an area of war. bullets are flying, SAM's are flying, its a bloody mess. An unsurvivable tanker has no chance. What they mean by survivable is that the Airbus is 5x more likely to be knocked out in time of war. If a missile hits the KC-767, it is designed to take the hit and possibly fly home. Kind of important in my book, especially in an age where stealth is near mandatory.
-S
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