Some years ago I was involved in a multinational AAR study. One topic to be covered was practical maximum fuel loads for future tankers. But rather than believe manufacturers' glossy brochure boasts, I set the following conditions for the departure and arrival aerodromes: Sea Level, ISA, still air, 10000 ft runway. Hardly very demanding and reasonably typical of most large European aerodromes.
The US representatives immediately asked for 12000 ft - which we refused on the grounds that neither Heathrow nor Frankfurt were typical tanker bases.
After each group had crunched the numbers, the answer was that both the A310MRTT and A330MRTT could operate with max fuel under those conditions. The 73.5T ex-ba B767-200ER proposed by TTSC for the FSTA contract was also just able do so.
Sorry BEagle, but I have to call BS. First off, BA never even had 767-200ERs, they were -300ERs. And 767 takeoff performance is just fine (as 1000 in-service passenger and freighter 767s can attest).
The 767-2C/KC-46 is designed for MTOW (415,000 lbs) at sea level from a 8,400 ft. runway up to corner point temp (+15C).
KenV, thanks for the objective and informed comments - in sharp contrast to most of what's been posted on this thread.