September 1, 2007  

The KC-X opportunity

Air Force Chief of Staff Gen. T. Michael Moseley often describes the "soul" of the Air Force as range and payload. Secretary of the Air Force Michael Wynne adds that he would "salt and pepper persistence in there as well," giving flavor to what the Air Force brings to the joint force. The request for proposal on the KC-X, the next- generation tanker, indicates that the Air Force may be asking its mobility forces to increase range, payload and persistence.

Although such increases in capacity will require new operational concepts to exploit the KC-X’s technical attributes, the trends in tanker and transport operations over the past 60 years suggest that extending air mobility’s range, increasing its fuel offload and growing its lift is a natural evolution.

Today’s airlift forces — C-17, C-5 and C-130 — were designed to meet the challenges of the Cold War and do so with fewer aircraft. The inter-theater C-141 replaced the C-124, C-54, C-119, C-121 and C-133, and the C-130 replaced the C-46, C-47 and C-123 for regional operations. From a budgetary perspective, Air Force officials justified the C-141 for its support to nuclear deterrence because of its ability to deploy medium bomber forces worldwide.

Likewise, the early Cold War’s nuclear deterrent mission justified the Air Force’s first jet air refueling aircraft — the KC-135. The Stratotanker replaced the KB-50 and KC-97 to support the B-47 and, later, the B-52. The Air Force justified the KC-135, an expensive aircraft acquisition, on the grounds that it provided more capability and enabled the nuclear deterrent mission at a reduced cost. The alternative to the jet bomber-tanker combination was nuclear armed naval aviation operating from a super-sized carrier. The Air Force argument won the day. The Air Force viewed the tanker-bomber pairing as so critical that both aircraft were often operated from the same Strategic Air Command (SAC) base.

Despite its nuclear mission rationale, the KC-135 proved vital to conventional combat operations, such as those in Vietnam. In that conflict, tankers flew more than 194,000 sorties and serviced roughly 250 aircraft per day. Without air refueling, fighters based in Thailand could not reach Hanoi and return. From this experience in Vietnam, Tactical Air Command (TAC) officials recognized the need to extend the fighter aircraft’s range and increased the number of air-refuelable TAC aircraft from 2,000 to 4,500.


One pattern persisted for airlift and tanker forces from World War II, the Korean War and into the Vietnam War era: Airlift and air refueling aircraft were single-purpose aircraft in design and operational employment. One key event changed that in the early 1970s: Operation Nickel Grass. Tasked to resupply Israel with 22,000 tons of materiel, Air Force airlift aircraft required en route air-to-air refueling (AAR) to reach Israel from the U.S. Although the C-5 was AAR-capable, most of its crews were not AAR-qualified. Therefore, the airlift operation needed en route bases. Only Portugal permitted the U.S. to use one of its airfields — Lajes Field in the Azores. Thus, Air Force officials learned two key lessons. First, airlift aircraft needed air-refueling capabilities. Second, dual-capable tankers-airlifters could be critical in a national emergency. The KC-10 emerged from that experience — the Air Force’s first multimission mobility aircraft.

The early 1990s marked the next significant event in the evolution of air mobility. Rapidly reinforcing Saudi Arabia required the tanker fleet to establish an aluminum air bridge to support the airlift force deploying air and ground forces to the region. Once hostilities began, tankers enabled deep strikes into Iraq. Compared with the Vietnam experience, the Desert Storm tankers conducted an average of 1,300 air refuelings per day. Just as important, Navy and Marine Corps strike aircraft now comprised nearly one in four aircraft receivers. Thus, the KC-135 that had once been reserved for B-52s now found its "customers" were not only Air Force fighters, but sister service aircraft as well. Desert Storm broke the Cold War coupling of tankers dedicated to bombers.

Then-Air Force Chief of Staff Gen. Merrill "Tony" McPeak understood Desert Storm as a watershed event and sought to realign the Air Force accordingly. With the creation of Air Mobility Command (AMC), he wanted to eliminate barriers between the functions of airpower. To advance this objective, SAC’s tankers and Military Aircraft Command’s long-range transporters merged into AMC.

In September 2001, the Air Force put these concepts to the test. Barely three weeks after the terrorist attacks on the U.S., the Joint Force undertook a major campaign in a place for which it did not have a prepared war plan: Afghanistan. Mobility forces quickly got the force in place — reinforcing Southwest Asia with command-and-control, bomber, reconnaissance, combat rescue and special operations forces. Once hostilities began, all bomber and fighter aircraft required air refueling to reach targets and establish a continuous presence over Afghanistan. This created an increased demand for fuel offload. Compared with the Desert Storm offload of 47,500 pounds per tanker, the Operation Enduring Freedom (OEF) tanker has provided 75,400 pounds per tanker, enabling strike aircraft to reach terrorist sanctuaries in Afghanistan.

If OEF has demonstrated the wisdom and efficiency of merging tanker and transport forces into the same command, it also has validated an earlier Air Force decision: making the KC-10 AAR-capable. The Air Force has learned many operational lessons in OEF about how to improve air mobility and, specifically, air refueling efficiency. Because most tankers do not offload all their fuel during a mission, mobility planners have had the "excess" fuel passed to AAR-capable KC-10s in the air. This innovative concept, known as "fuel consolidation," has extended the KC-10s’ on-station time by roughly 80 percent. With extra station time and fuel, KC-10s conducted unscheduled air refueling on 35 percent of their missions. Air Force officials estimate that this practice decreased required air refueling missions by at least 20 percent. In an environment where "time-sensitive targeting" and "dynamic tasking" redefined air operations, the tankers’ extra gas — and the ability to get it on short notice — increased air power’s flexibility and enabled a very critical element of the joint campaign against Taliban and terrorist targets.

OEF also has another prudent Air Force investment: the C-17, which has demonstrated its versatility as a complement to the C-5 fleet for oversized cargo and a supplement to the C-130 for long-range air-land/air-drop missions. With a fleet of fewer C-17s replacing the older and larger C-141 force, the Air Force has shown that air power is about effects and not the number of aircraft on the ramp. A more efficient aircraft has not just replaced a larger but less versatile platform, the C-17 also surpassed the C-141’s capability. The Air Force leadership’s vision has been validated.

The trends in the airlift and air refueling fleets over the past six decades reflect fewer airframe types performing a wider variety of missions. However, the tanker community has slowly embraced the transport mission. For example, during a typical year, U.S. Air Forces in Europe’s KC-135s based at RAF Mildenhall in the U.K. carry passengers or cargo on less than 4 percent of their annual missions (while flying 25 percent training missions). Since the war on terrorism began, however, AMC has increased the tankers’ role in supplementing airlift missions. Over the past five years, AMC tankers have delivered 197,000 passengers and more than 50,000 tons of cargo. Such efforts eliminated the need for 3,300 C-17 missions.

The tendency to turn to tankers to augment the airlift forces stems from the operational demands on the air mobility fleet — demands that exceed current capabilities. Airlift deficits have been documented in a number of ways. Since the early 1990s, the Defense Department has conducted a series of mobility requirement studies (MRS) to address the nation’s military transportation needs. The updated MRS 2005 articulated the airlift requirement deficit at 4.8 million ton miles per day (MTM/D). By altering the underlying assumptions, a more recent mobility capability assessment indicated that there was no shortfall in capacity. However, AMC leadership and officials working daily with the airlift system have a different opinion. Based on their experience supporting operations in Iraq and Afghanistan, plus other U.S. global commitments, they maintain that the mobility shortfall is as high as 10 MTM/D.

A shortage of air refuelers also exists but gets less notice. In June 2000, a Government Accountability Office study posited a 14 percent shortfall in terms of fuel available per day and a 19 percent shortage in terms of aircraft. This shortfall has been worsened by the demands of the high sustained tempo of the Iraq and Afghanistan operations and the age of the Eisenhower-era KC-135. The result: the Air Force has declared tanker replacement its No. 1 acquisition priority.

The shortfall in air refueling and airlift capability is adversely affected by other factors. One is airfield access, which has changed significantly in the last 50 years. When today’s tanker and transport forces were fielded, the U.S. focused on post-World War II Europe, where planners had access to 55 airfields per 1 million square miles. Today, as the U.S. military operations shift south and east from Europe, airfield density drops to just 13 airfields per 1 million square miles in that region.

With the KC-X acquisition, the Air Force recognizes an opportunity to address deficits in air fueling and airlift with an effects-based approach. Given the shift in U.S. interests to Africa, the Middle East and Asia, where distances between airfields are greater, the Air Force’s global reach capabilities will be more critical. Operating at extended range could include situations where bombers are needed for precision strike or C-17s to air drop/air land humanitarian supplies. Such scenarios will increase the demand for greater fuel offload at farther distances. A KC-X with more capability than the KC-135 could meet the demands of a few large receivers or numerous fighters with fewer sorties.

When one considers the Air Force’s future fighter force of F-22s and F-35s, the demand for fuel within a theater of operation will change. Although the overall fighter aircraft inventory will decline significantly through 2030, their average air refueling requirement will increase to meet greater sortie length and persistence. Thus, the overall booms needed by 2020 or 2030 will be less — but they must deliver more.

There are advantages to fielding the next-generation tanker/mobility aircraft with dual capabilities of air refueling and lift; however, the aircraft must be matched with operational concepts. Current operational experience suggests three scenarios in which the joint force would value innovative, multimission capabilities.

One scenario would have the KC-X perform both airlift and air refueling missions on the same sortie when supporting daily operations in the deployed environment. For example, today, AMC tanker and transport aircraft operate out of Manas Air Base, Kyrgyzstan, to support coalition forces in Afghanistan. If tasked, to exploit its dual-mission capability, the KC-X could be uploaded with both cargo and fuel, launch on an air-refueling mission over Afghanistan, then land at Bagram Air Base and offload the cargo. Such a concept would reduce the U.S. footprint, decrease fuel consumption and place fewer airmen in harm’s way.

A second scenario would involve deploying fighter or bomber squadrons while embracing the KC-X’s dual tanker-transport capability. Today, deploying an F-22 squadron using separate airlift and air refueling aircraft would require 82 KC-135s and C-17s. Using generic analysis of the two aircraft that the aerospace industry may offer for the KC-X, the number of mobility aircraft could be reduced to 64 — a minimum of a 22 percent reduction. The greater the refueling and lift capability of the KC-X, the greater the savings can be in terms of aircraft, sorties and associated support infrastructure.

Finally, the AC-130 strike against al-Qaida terrorists in southern Somalia earlier this year suggests another new doctrinal use of the next-generation mobility aircraft. Because of the lack of U.S. presence at the target location, it took days to confirm whether Fazul Abdullah Mohammed, the ringleader of the attack on the U.S. embassies in Kenya and Tanzania, was killed.

A KC-X capable of air refueling CV-22s plus transporting Special Forces ground units and a joint task force command element could deploy to a base where the target area was within CV-22 range of the target. At the deployed base, the KC-X functions as a forward air-refueling point for the tilt-rotor aircraft. Equipped with a network-centric, open architecture to accommodate a command-and-control module, the KC-X could launch as an airborne C2 node, providing updated intelligence so the strike aircraft could find, fix and target the terrorists. It could then integrate the insertion of special operations forces to follow up in the target area after the strike.

These three examples suggest the KC-X’s potential to advance the vision of AMC as the right command to move air refueling and airlift to a higher level — being a true mobility provider. These scenarios build on the trend within the mobility community within the past 60 years — to consolidate aircraft, capabilities and missions within fewer airframes and aircraft types while being more flexible in employment. They also reflect the Air Force intellectual investment in effects-based operations and extending that mind-set into acquisition efforts.

Mobility airmen have long provided adaptable and multi-mission capability to the joint force and the nation. Given the operational demands and the expected budgets of the near future, fresh and innovative approaches that exploit multirole and multimission capabilities will be needed. The Air Force appears poised to field an aircraft that allows that potential to become a reality.

Michael Isherwood is the senior air analyst in the Northrop Grumman Analysis Center. Previously, he served in the Air Force as a colonel with command positions from squadron to wing levels.