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KC-Z - KC-135R Replacement

The Air Force revised its acquisition strategy and plans to recapitalize the aerial tanker fleet by developing three consecutive acquisition programs: KC-X, KC-Y, and KC-Z. The intention of those programs was to represent different tanker aircraft platforms. Follow-on programs, the KC-Y and KC-Z, will replace another 300-plus KC-135s and 59 wide-body KC-10s. Air Force staff have described the KC-Y and KC-Z programs as budgetary "off ramps."

The KC-Z, to replace the KC-135Rs is planned for the 2027-2036 time-frame. The Air Force intends to replace the fleet of more than 500 KC-135s, and the Mobility Capabilities Study of 2005 set the requirement for KC-135s at a range of between 520 to 640 aircraft. Replacement of this fleet is estimated to cost a minimum of $72 billion. The plan calls for procurement of nine KC-Zs a year until 2048.

The Air Force projected that the KC-135R models have lifetime flying hour limits of 39,000 hours. 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 has between 12,000 to 14,000 flying hours per aircraft, which is approximately 33 percent of the lifetime flying hour limit. Nevertheless, these aircraft are currently over 40 years old and plagued with maintenance problems resulting in an increase in costs. In 1996 it cost $8,400 per flight hour for the KC-135, and in 2002 this had grown to $11,000.

The Air Force completed an Analysis of Alternatives (AoA) in Apr 2006 to determine the most appropriate strategy to recapitalize the aging fleet of KC-135 aerial refueling aircraft. Based on this analysis, the Air Force concluded that a strategy of full and open competition to select a commercial derivative replacement tanker aircraft would result in a best value tanker contract. Replacement of the legacy KC-135 fleet will take place in three stages, known as the KC-X, the KC-Y, and the KC-Z. the Department of Defense continues to develop a long-range plan to replace the KC-10 Extender and KC-135 Stratotanker fleets with the KC-46A Pegasus, as well as the KC-Y and KC-Z programs.

In 2016 Lockheed Martin unveiled its concept of next-generation wing-body tanker aircraft for refuel fighters like the F-22 and F-35. The concept of new stealth tanker aircraft was displayed for the first time at AIAA SciTech Forum. Lockheeds vision builds on the companys Hybrid Wing Body (HWB) concept for a more fuel-efficient future airlifter.


"Popular Science" website published on 20 September 2017 Kel A. Atherton's report titled "Air Force Commander Adds Stealth Tanker to Wish List". The range of a fighter jet is mainly limited by how much fuel it can carry. Airborne refueling is an ordinary and challenging action that allows fighter jets to fly far beyond the distance that a tank of oil can support, and strikes targets that are normally inaccessible. At present, air refueling is best carried out in friendly airspace because tankers and fighter aircraft that are staying around them are vulnerable to enemy attacks. But what if this is not the case? If the tanker itself is invisible?

Lee Gian Greco reported in "Flying Global" magazine: "This year, the Air Force will start a study to find out what the KC-Z refueling opportunity looks like and will start looking for investment opportunities one year after the completion of the study. Is considering whether this new type of tanker should include off-premises operations, invisibility, or penetration capabilities for anti-intrusion/zone deterrence environments.. US Air Force general Carlton Everhart said that the F-35 stealth fighter entered anti-involvement After the area rejects the environment, a tanker with low detectability should follow."

Greg Greco quoted Everhart as saying: "We will need a brand new platform. It is a wing-body fusion layout body that has low detectability characteristics."

The Air Force is exploring the possibility of developing a stealth tanker. The advantage of this military aircraft is that it can fuel other stealth fighter planes in areas that are dangerous or difficult to access for non-stealth fighters. Its main drawback is that stealth fighter planes are faced with unique airframe design constraints. These design limitations, coupled with the complicated procurement process, mean that these fighters are always very expensive. It's not too hard for us to imagine an invisible refueling opportunity falling into the same R&D trap as the F-35, or as highly confidential as the B-21. But under the ambitious plans of the US Air Force to purchase 1,700 stealth fighter aircraft and up to 200 stealth bombers, the development of stealth tankers may still be a dream.

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