Red Herring Cargo
There is hardly a greater freighter than the DC-10 or MD-11, yet the USAF does not use their KC-10A fleet for regularly hauling cargo. The missions of cargo and refueling don't normally coincide. The 767 is an oddball for hauling cargo, so what?
According to Wiki, the KC-135 fleet is largely used in theatre, while the KC-10A are used over the pond.
The economics of buying a plane to last for 50 years is laughable. Most of the KC-135 fleet have had two engine changes, from J-57 to TF-33 (from retired 707s) to CFM-56.
"As of 2006, the KC-135E fleet is flying an annual average of 350 hours per aircraft and the KC-135R fleet is flying an annual average of 710 hours per aircraft. The KC-135 fleet is currently flying double its planned yearly flying hour program to meet airborne refueling requirements, and has resulted in higher than forecasted usage and sustainment costs.
The Air Force projects that E and R models have lifetime flying hour limits of 36,000 and 39,000 hours, respectively. According to the Air Force, only a few KC-135s would reach these limits before 2040, but at that time some of the aircraft would be about 80 years old. The Air Force estimates that their current fleet of KC-135s have between 12,000 to 14,000 flying hours on them-only 33 percent of the lifetime flying hour limit. Nevertheless these aircraft are over 40 years old and maintenance costs are increasing, with airframe corrosion being the worst problem."
It's better to put 767-200ERs into semi-retirement at a few hundred hours per year, with total cost undoubtedly under $50 Million each, vs. brand new $200 Million whatevers. There may even be used 737s that fit the mission, or a combination of 737s and 767s.
In order of utilization, hauling pax on scheduled ops is normally highest, followed by various cargo ops, and aerial refueling is near the bottom.
Fedex and UPS, two of the world's most successful airlines, buy new planes only when used ones are not available for the mission. Fedex has even spent $50 Million a copy to create the MD-10, a DC-10 with MD-11 cockpit.
The USAF should contract with Fedex and UPS to take their half-life or third-life 767s and MD-11s, and convert them to tankers.
The A330 refueler is supposedly scheduled to replace the KC-10A fleet. The A330F empty operating weight is 109 metric tons and takeoff max is 230t. The KC-10A base DC10-30 EOW is 121t and max 260t. That's in the same league, but not quite a direct replacement.
The MD-11 empty operating weight is 113t and max takeoff weight is 286t. Now there's a real fuel farm.
GB