April 28, 2020
Air Force F-15EX Fighter Program
In FY2020, the Trump Administration proposed to buy
would have 70% parts commonality with existing U.S. F-
eight F-15EX aircraft for $1.1 billion, the first installment
15s.
toward a planned initial buy of 144 planes. Subsequently,
Congress authorized $985.5 million and appropriated $1.05
Why is the Air Force requesting F-
billion for the program. The Administration’s FY2021
15EXs?
budget requests $1.27 billion for 12 more F-15EXs; the
plan set forth in FY2020 had called for 18 in FY2021.
Air Force officials have offered numerous justifications for
the F-15EX:
This acquisition represents a change from previous Air
Force plans to procure only stealthy “fifth-generation”
The Air Force is engaged in upgrades to its existing F-
fighter aircraft. What is an F-15EX, and why might the Air
15 fleet. While costing more per aircraft than
Force have changed plans?
modernizing legacy F-15s, a new F-15EX would yield
more future life. Replacing the older, 1980s-era F-15Cs
What is an F-15EX?
with F-15EX could also enable the Air Force to avoid
the cost of some or all of those upgrades. “The Air
The Air Force received its first F-15 Eagle air superiority
Force has tried to retire its 250 aging F-15Cs and two-
fighter in 1974. Subsequently, the F-15 evolved to
seat F-15Ds over the years due to structural issues with
encompass more roles, most notably with the deployment
the aircraft, including most recently in 2017. Now,
of the F-15E Strike Eagle in 1989. The F-15E added
instead of paying to upgrade the older aircraft in the
substantial air-to-ground capability, including a second
fleet, the Air Force hopes to use that money to buy
cockpit for a weapons systems operator. The Air Force has
Boeing’s F-15EX.”
453 F-15s of all variants, the last of which was ordered in
2001. Since then, F-15s have been continuously produced
Buying F-15s, according to the Air Force, is an
for a variety of international customers, including (among
economical way of reaching the service’s goals for
others) Israel, Saudi Arabia, and Japan.
fighter fleet size and average age. “Gen. James ‘Mike’
Holmes, head of Air Combat Command, told reporters
Figure 1. F-15EX Concept
in February that purchasing the F-15EX could be the
‘affordable answer’ to meeting the Air Force’s goal of
acquiring 72 new fighter jets each year.”
F-15s could also cost less to operate over time than
fifth-generation fighters like the F-35. (The per-hour
cost of F-15s is fairly well established, while there is
less real-world experience with the F-35 fleet; a direct
comparison is difficult.)
Because the Air Force already operates F-15s, transition
to the F-15EX could be comparatively easy. “We made
the determination to buy F-15EXs so that we could keep
our readiness at a higher level and meet the capacity
need that we had for those fourth generation platforms.
That is important from a readiness perspective because
the time to transition from an F-15C to an F-15EX we
estimate at 3 to 6 months, while the time to transition
Source: Boeing.
from an F-15C to an F-35 could be anywhere from 18 to
Current F-15s have stronger airframes and more advanced
36 months and would require MILCON and other
sensors, processors, and flight control systems than those in
attributes that are not in our budget.”
the U.S. fleet. Many also include conformal fuel tanks to
extend range and increase payload. The proposed F-15EX
F-15EX procurement helps maintain a competitive
would be based on the most advanced Eagles, currently
fighter aircraft industrial base. Currently, Boeing and
entering production for Qatar, which first flew on April 14,
Lockheed Martin are the prime contractors supplying
2020. F-15EXs would add radar and other subsystems
fighter jets to the Department of Defense. A National
unique to the United States. Boeing says that the F-15EX
Defense magazine report stated:
https://crsreports.congress.gov
Air Force F-15EX Fighter Program
After the decision was made to continue with a
18 aircraft through FY2023 in its FY2020 and FY2021
mix of fourth- and fifth-generation aircraft,
budget submissions. This may not be a direct correlation,
“the conversation then turned to how are we
but has led some to see a tension between the two
going to maintain a robust industrial base,” a
programs.
Pentagon official, who declined to be named,
official told reporters.
Although the F-15EX acquisition was proposed as a sole-
source contract outside of the normal requirements-
“For the future of the Department of Defense,
definition process, Congress acted to retroactively require
it’s going to be good to have multiple providers
much of the same documentation. The FY2020 National
in the tactical aircraft portfolio … and that’s
Defense Authorization Act and the explanatory statement
what led our way into the F-15EX decision,” he
accompanying the FY2020 Defense Appropriations Act
added.
require the Secretary of the Air Force to provide an F-15EX
acquisition strategy, cost and schedule estimates, and
Former Air Force Secretary Heather Wilson said that the
strategies for test and evaluation, logistics, and post-
Air Force did not request the F-15EXs in its initial FY2020
production fielding. The appropriations statement also
budget submission. This proposal appears to have been
requires a capability production document and life-cycle
added by the Office of the Secretary of Defense during the
sustainment plan.
budget build process, without a request for proposals or
explanation. However, Wilson and other Air Force officials
Possible questions
subsequently advocated for the F-15EX. “‘We are seeing a
decline in the number of fighters available, the increase in
Should acquisition of new fighters be a competitive
the average age of those fighters, and if we look at the
procurement?
whole system and the whole capacity over the next 10 to 20
years, one of the airframes that is not going to make it is the
What are the relative costs of upgrade and modernizing
F-15C,’ Wilson said.” “We need to replace those F-15Cs
existing F-15s as opposed to buying new ones? How
with something.” Gen. Arnold Bunch added, “We have now
many flight hours does the Air Force expect to get from
looked at … what it takes to modernize that capability up in
the jets in each case?
an F-15C, and the determination we made was that was not
what we needed to do.”
If new F-15EXs are purchased, would the Air Force
retire older F-15s rather than upgrading them? How
Does the F-15EX replace the F-35?
many upgrades would be foregone for each new F-15
purchased?
The Air Force has been at pains to emphasize that the F-35
and F-15EX are not rivals, but complementary. The F-35
How does the replacement of F-15s fit with the Air
brings superior stealth and sensor fusion; the F-15 can carry
Force’s declared goal of growing to 386 squadrons?
more payload. (Air Force officials describe this as the
difference between “capability” and “capacity.”) The
If stealthy aircraft are only required in a given conflict
message of different missions can also be seen in the
until the air defenses are taken down, which allows
emphasis on F-15EX as an alternative to modernizing
older-technology aircraft to operate with impunity, does
existing F-15s in their existing roles.
it make sense to size the buy of fifth-generation aircraft
using requirements for the early phases of conflict?
Given a fixed Air Force budget topline, however, increases
in one program require cuts in others. According to Air
What is DOD’s commitment to completing the planned
Force Chief of Staff General David Goldfein, “If we had
buy of F-35As?
the money, those would be 72 F-35s. But we’ve gotta look
at this from a cost/business case.” He also noted, “We are
How does the F-15EX fit with the current National
absolutely adamant that the F-35 program, the program of
Military Strategy emphasizing capability against
record, absolutely stays on track and we don't take a dime
sophisticated adversaries?
out of the F-35.”
While maintaining the planned purchase of 48 F-35As in
Jeremiah Gertler, Specialist in Military Aviation
FY2020, the Administration reduced its projected buy by
IF11521
https://crsreports.congress.gov
Air Force F-15EX Fighter Program
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