Order Code RS20941
Updated March 20, 2007
Air Force Aerial Refueling
Christopher Bolkcom
Specialist in National Defense
Foreign Affairs, Defense, and Trade Division
Summary
Aerial refueling aircraft are key to air operations. The U.S. tanker fleet is large and
effective, but old. Modernizing or replacing the current fleet of tankers presents the
Department of Defense (DOD) with difficult choices in terms of desired capabilities,
force structure, and budget. How this fleet will be maintained or replaced, and on what
schedule, has proven controversial. This report will be updated as events warrant.
Background
Modern military air operations require aerial refueling. Refueling aircraft, or tankers,
extend the range of fighters, bombers, and other aircraft. Tankers increase the range and
flexibility of projection forces. They increase the amount of time that combat and
surveillance aircraft can stay “on-station,” and they boost combat aircraft lethality.
According to senior Air Force officials, “Clearly the tanker fleet is really some of the
very fiber that holds our Air Force’s unique global capabilities together. It is an essential
enabler for getting to the fight and fighting the fight.”1 Navy aircraft can be configured
to refuel other Navy or Marine Corps aircraft, but the Navy prefers to use “big wing” Air
Force tankers for long-range flight operations.2 Air Force and Department of Defense
(DOD) leaders believe they need 550-650 KC-135-like aircraft.3
Air Force Capabilities. The majority of the Air Force’s tankers are Boeing KC-
135 Stratotankers. The Air Force owns 502 Stratotankers: 85 “E” models, and 417 more
capable “R” models. The average KC-135 is approximately 45 years old. The KC-135 can
carry 200,000 lbs of fuel that it dispenses to USAF aircraft through a flying boom. A
drogue can be attached to refuel Navy, Marine Corps, or allied-country aircraft. The
1 A. Butler, “Air Force Mulling Replacement for Aging, Maintenance-Needy KC-135,” Inside
the Air Force, May 4, 2001.
2 Department of the Navy (N78) provided to CRS by email Sept. 2, 2005.
3 See, for example, Tanker Requirements Study-05. Department of the Air Force, Air Mobility
Command. February 2001, and Mobility Capabilities Study (MCS). December 2005.
CRS-2
Multi-Point Refueling System Program outfits 20 KC-135Rs with wingtip pods so the
aircraft can simultaneously refuel two probe-equipped aircraft. The KC-135 can also carry
35,000 lbs of cargo in addition to its fuel payload. KC-135s are expected to fly until 2040.
The Air Force also owns 59 Boeing KC-10A Extenders. The KC-10 has an average
fleet age of approximately 22 years. The KC-10 is more flexible and more capable than
the KC-135. It can carry twice as much fuel as the Stratotanker, (356,000 lbs) and can be
refueled in the air to increase delivery range or on-station time. All KC-10s use the flying
boom, and 20 can employ wing tip probe and drogue systems. The KC-10 can carry up
to 75 troops and 170,000 lbs of cargo in addition to its fuel payload, representing
approximately 3% of all of DOD’s organic airlift capability. Current plans call for the
KC-10 to remain in the active inventory through 2040.
A brief review of recent conflicts underscores the importance of tanker aircraft. In
both Iraq and Afghanistan, U.S. military aircraft projected power over long distances and
in theaters with less than desirable access to forward bases or neighboring airspace. Thus,
combat and support aircraft had to fly great distances both to the theater and while in
theater, increasing aerial refueling demands. A large proportion of the Air Force’s aerial
refueling fleet (149 KC-135s, and 33 KC-10s) participated in Operation Iraqi Freedom,
flying over 6,000 sorties and offloading over 300 million pounds of fuel.
Modernization Controversy. Modernizing or replacing the Air Force tanker
fleet has been a point of contention for 10 years. In 1996, the General Accounting Office
(GAO) asserted that the long-term viability of the KC-135 fleet was questionable and
advocated expeditiously studying replacement options. DOD countered that KC-135
airframe hours were low and that the fleet was sustainable for another 35 years.4 In 2001,
the Air Force reported that the KC-135 fleet would incur “significant cost increases”
between 2001 and 2040, but “no economic crisis is on the horizon...there appears to be
no run-away cost-growth,” and “the fleet is structurally viable to 2040.”5 At that time, the
Air Force position on tanker modernization was to conduct an analysis of alternatives
(AOA) to determine the optimal replacement option for KC-135s. Recapitalization would
begin in the 2012 time frame to meet the KC-135 2040 retirement.
Section 8159 of the FY2002 DOD Appropriations Act (P.L. 107-117) authorized the
Air Force to lease 100 Boeing KC-767 aircraft to replace the oldest KC-135Es. This
proposal proved controversial because section 8159 appeared to depart from traditional
acquisition processes and to weaken congressional oversight. It was also established that
a lease would cost more than procuring the aircraft, and many found Air Force arguments
in favor of the lease to contradict its position of just a year prior. The proposed lease was
debated in four congressional hearings, culminating with a pair of Senate hearings in
September 2003.6 Subsequently, alleged and admitted ethical violations by government
and industry representatives involved in the lease proposal added to the controversy.
4 GAO/NSIAD-96-160.
5 “KC-135 Economic Service Life Study,” Technical Report F34601-96-C-0111, Feb. 9, 2001.
6 See CRS Report RL32056, The Air Force KC-767 Tanker Lease Proposal: Key Issues For
Congress, by Christopher Bolkcom.
CRS-3
The FY2004 Defense Authorization Act (P.L. 108-136, Sec.135) forged a
compromise between opponents and proponents of the KC-767 by giving the Air Force
permission to lease 20 tanker aircraft and purchase 80 aircraft. Section 134 of this act
prohibited the Air Force from retiring in FY2004 more than 12 KC-135Es. In September
2004, it was announced that the Air Force had grounded 29 KC-135Es due to safety
concerns. Conferees also mandated that the Air Force conduct an aerial refueling AOA
and that an independent assessment be conducted on the condition of the KC-135E fleet.
On February 1, 2004, former Deputy Secretary of Defense Paul Wolfowitz requested
that the Defense Science Board (DSB) conduct the independent analysis of the KC-135E
fleet, and on February 24, 2004, former acting Undersecretary of Defense for Acquisition
Michael Wynne directed the Air Force to conduct an aerial refueling AOA. Although it
had the statutory authority to proceed, DOD did not request any funds for FY2005 to lease
20 aircraft or procure 80 aircraft. Defense Department leaders instead deferred executing
either action until the completion of the DSB report, and an internal investigation by the
DOD Inspector General (IG) on potential improprieties by Boeing Company executives
and whether these activities negatively effected the Tanker lease program.
On April 20, 2004, Darleen A. Druyan, the former lead Air Force negotiator on the
tanker lease program, pleaded guilty to one charge of criminal conspiracy. Ms. Druyan
admitted to secretly negotiating an executive job with the Boeing company while still
overseeing the $23 billion deal between the Air Force and Boeing.7 Lease supporters
argued that Ms. Druyan was a single “bad apple” and that her actions did not negate the
KC-767’s merits. In February 2005, however, it was reported that the DOD IG found that
Air Force Secretary James Roche misused his office when he lobbied the Office of
Management and Budget (OMB) to support the lease concept.8 The IG’s final report
found that four other senior DOD officials were guilty of evading OMB and DOD
acquisition regulations that are designed to demonstrate best business practices and to
provide accountability. The DOD IG found that senior DOD officials knowingly
misrepresented the state of the KC-135 fleet and aerial refueling requirements.9
Issues for Congress
As DOD pursues its KC-135 recapitalization program, several issues appear to
compete for congressional attention.
Is it fair?. There has been much dialogue in the media that the first draft of the KC-
X request for proposal ( RFP) was biased toward the capabilities apparent in the KC-767.
Close review of this RFP is understandable in light of the controversy surrounding past
tanker recapitalization efforts. It is important to note within this context, that the driving
force behind DOD’s weapon acquisition system is designed to be warfighter
requirements, not what is most profitable to company x or company y. Northrop
Grumman and Airbus reportedly complained that the original KC-X RFP did not
7 R. Merle, “Ex-Pentagon Official Admits Job Deal,” Washington Post, Apr. 21, 2004.
8 R. Jeffrey Smith, “Roche Cited for 2 Ethics Violations,” Washington Post, Feb. 10, 2005.
9 Management Accountability Review of the Boeing KC-767A Tanker Program, Office of the
Inspector General of the Department of Defense, OIG-2004-171, May 13, 2005.
CRS-4
adequately address how the candidate aircraft’s airlift capability would be evaluated, and
they feared that the Air Force might not look upon the airlift capabilities of their aircraft
(the larger KC-30) as favorably as it should.
In the absence of detailed airlift evaluation information, however, Airbus could have
offered a smaller aircraft, such as its A300/A310 class, which it might believe
corresponded more closely to Air Force requirements.10 Similarly, if Boeing believed the
Air Force desired a larger aircraft with more airlift capability, it could have conceivably
offered its 777 aircraft.
Reduced demand of defense-unique systems and the resulting consolidation of the
defense industrial base has frequently reduced the number of companies available to
provide a given defense article, which adversely affects competition. Therefore, some
compromise between a warfighter’s “perfect world” requirements and real world
industrial capabilities is inevitable. However, substantially modifying warfighter
requirements or Key Performance Parameters (KPPs) to jibe with what industry wants to
offer, would appear to reflect an imbalance between requirements and capabilities.
As DOD defines its requirement, there appears to be nothing obvious in the KC-X
RFP that would inherently bias the contract award in favor of any platform that could be
offered by the competitors. The RFP makes clear, however, that the aircraft’s primary
mission is refueling DOD and allied aircraft with the flying boom mechanism. Any
passenger or cargo carrying capability is deemed a “secondary mission.”
Is it affordable?. DOD’s Aerial Refueling Analysis of Alternatives (AR AOA)
found that purchasing new commercially-derived tankers was the most cost effective
means of initially recapitalizing the fleet.11 This conclusion appears to be widely shared
among defense analysts. However, this course of action is also capital intensive when
compared with other potential courses of action, and the AR AOA noted that
“affordability (annual budget outlays)” was an important factor that should “drive the
acquisition schedule for tanker recapitalization.”12
At one time, the KC-X program was described as a 540-aircraft effort. The recent
Air Force description of the 179-aircraft KC-X program, however, portrays it as the first
of three potential efforts – followed by the KC-Y and KC-Z, which combined, would add
up to approximately 540 new tanker aircraft. This new conceptual framework may
indicate implicit Air Force recognition that 540 new aircraft are likely unaffordable: Air
Force staff have described the KC-Y and KC-Z programs as budgetary “off ramps.”13
Therefore, Air Force leaders might conceivably be more receptive to Congressional
direction on other potential recapitalization options for the KC-Y and KC-Z programs.
10 The last A300/A310 class aircraft are estimated to be produced in July 2007. The A300/A310
production line is in the process of being terminated. However, if Airbus believed that a medium
sized tanker was more compatible with Air Force requirements and therefore more competitive
than a larger A330-class aircraft, Airbus could have taken steps to keep the line open.
11 KC-135 Recapitalization Analysis of Alternatives. Briefing to Congress. January 26-27, 2006.
12 Ibid. p.5.
13 Meeting between CRS and SAF/AQQ April 4, 2006, and follow-on interviews.
CRS-5
The 2004 DSB Task Force on Aerial Refueling Requirements was an early
proponent of examining less capital-intensive recapitalization options. The DSB
recommended that DOD give “serious consideration” to purchasing surplus commercial
aircraft such as the DC-10, re-engining some fraction of the KC-135E fleet, and
expanding its use of commercial Fee-For-Service aerial refueling (FFS AR).
The Air Force has consistently argued against re-engining KC-135Es and purchasing
surplus commercial aircraft. However, the AR AOA appears to agree with the DSB –
although with distinct caveats – that purchasing used aircraft may merit additional study.
The AR AOA found that purchasing used aircraft as tankers is “generally not as cost
effective” (as purchasing new aircraft), but “...close enough in estimated cost to not
exclude it from competition.”14 Surplus DC-10 aircraft, in particular, might offer
attractive means of acquiring aerial refueling capabilities for less money up-front, and
since the Air Force already operates KC-10 aircraft, significant additional investments
may not be required in operations, maintenance, and supply.
Similarly, the AR AOA did not rule out re-engining some number of KC-135Es. The
study found that re-engining “E” models was “not a favorable return on investment
unless operated into late 2030s.”15 In an earlier study, the Air Force concluded that the
KC-135E fleet is “structurally viable until 2040.”16 A 2005 Air Force Study estimated,
with numerous caveats, that KC-135E aircraft upgraded to the “R” configuration would
remain viable until 2030.17 When evaluating these life-span projections, it may be useful
to review the findings of a third party. The DSB found that KC-135 corrosion problems
(a major determinant of costs and life span) were more manageable than Air Force
statements led some to believe, and that current and projected KC-135 operations and
support costs were also less than Air Force projections. If the DSB is correct, this may
lend credence to a longer life-span for KC-135 aircraft.
In FY2008, the Air Force proposes to retire its last 85 KC-135E aircraft, giving
Congress one last opportunity to assess the pros and cons of investing approximately $45
million per aircraft to re-engine some number of “E” models. If Congress believed that
the Air Force’s aerial refueling budget was unsustainable, re-engining 10 KC-135E
aircraft for $450 million and operate them until 2040 might appear more favorable than
acquiring some number of new tankers at a procurement cost of $120-$150 million each.
The KC-X RFP, “Part B” addresses Fee-for-Service aerial refueling (FFS AR), but
many have questioned the strength of the Air Force’s commitment to this recapitalization
approach.18 At one point the Air Force planned to complete a FFS AR Business Case
Analysis (BCA) in December 2006, and to let an RFP in January 2007 “if merited.” (A
CRS assessment of the proposed BCA methodology and assumptions can be found in
Appendix 2 to this statement.) The current status of FFS AR is unclear.
14 AOA Briefing to Congress. Op. Cit.
15 AOA Briefing to Congress. Op. Cit.
16 KC-135 Economic Service Life Study. Technical Report. February 9, 2001.
17 KC-135 Assessment Report. Air Force Fleet Viability Board. September 2005.
18 CRS interviews with congressional staff, Air Force, and industry (Oct. 2006 to Feb. 2007).
CRS-6
Will DOD’s plans produce what is needed?. It is difficult to evaluate DOD’s
recapitalization plan because there is no current or clear tanker requirement study. The
last comprehensive tanker requirement study performed by DOD was the Tanker
Requirements Study 2005, or TRS-05, which was completed in 2001. TRS-05 concluded
that to meet the National Military Strategy, DOD required 500-600 KC-135R -
equivalents, with an 85% Mission Capable Rate, and 900-1,000 aircrews, for a crew ratio
of 1.66 crews per aircraft to 1.92 aircrews per aircraft. The Mobility Capabilities Study
reportedly recommended the acquisition of 520 - 640 KC-135R model equivalents.19
Because DOD’s last tanker requirements study is outdated, and because subsequent
analyses failed, for many, to provide insight into tanker and airlift requirements, many
significant questions remain unclear. For example, how much airlift capability should the
aerial refueling fleet provide?” Some within DOD appear to believe that the KC-X
should provide more airlift capability. In April 2006, DOD’s top military transportation
commander expressed a strong preference for a multi-role tanker. Gen. Norton Schwartz,
Commander U.S. Transportation Command (TRANSCOM) testified that
What we need is a multi-mission tanker that can do both boom and basket refueling,
that can do passenger lift, some cargo lift, and have defensive systems that allow the
airplane to go wherever we need to take it....if we’re going to war with Iran or Korea
or over Taiwan or a major scenario, the first 15 to 30 days are going to be air refueling
intensive. But what I’m talking about is the global war on terrorism, sir, for the next
15 or 20 or 25 years. That is not an air refueling intensive scenario and that’s why a
multi-mission airplane to me makes sense.20
The DSB agreed with Gen. Schwartz’s opinion on refueling requirements and the
availability of tankers to provide airlift missions. “The major driver for future aerial
refueling needs is the number and type of nearly simultaneous “major” operations.
Demands on aerial refueling are particularly stressed when time is of the essence for the
mission and when local infrastructure is immature.”21
The amount of airlift ultimately to be provided by the tanker fleet could have
important implications for other air mobility programs. The Air Force’s 59 KC-10
Extender aerial refueling aircraft currently represent approximately 3% of DOD’s organic
airlift capability. The procurement of larger KC-X aircraft could increase the percentage
of airlift capacity provided by the tanker fleet, and could potentially reduce the number
of cargo aircraft such as C-5s and C-17s. The procurement of smaller KC-X aircraft could
potentially have the opposite effect. In the April 2006 hearing, Gen. Schwartz testified to
this trade-off: “If I had an airplane that could carry passengers there with defensive
systems, like a new tanker, I would use that instead, and we would be able to better
manage the workload on the C-17 fleet and apply it against the things that it does
exceptionally well, moving cargo.”
crsphpgw
19 KC-135 Tanker Replacement (KC-X) Program. SAF/AQQM. FY08 Staffer Brief. Feb. 2007.
20 “Senate Armed Services Subcommittee on Seapower Holds Hearing on FY2007 Budget:
Transportation Command.” CQ Congressional Transcripts. April 4, 2006
21 Defense Science Board Task Force on Aerial Refueling Requirements. Office of the Under
Secretary of Defense For Acquisition, Technology, and Logistics. May 2004. p. vi.