https://crsreports.congress.gov
Updated September 2, 2020
Air Force F-15EX Fighter Program
In FY2020, the Trump Administration proposed to buy
eight F-15EX aircraft for $1.1 billion, the first installment
toward a planned initial buy of 144 planes. Subsequently,
Congress authorized $985.5 million and appropriated $1.05
billion for the program. The Administration’s FY2021
budget requests $1.27 billion for 12 more F-15EXs; the
plan set forth in FY2020 had called for 18 in FY2021.
This acquisition represents a change from previous Air
Force plans to procure only stealthy “fifth-generation”
fighter aircraft. What is an F-15EX, and why might the Air
Force have changed plans?
What is an F-15EX?
The Air Force received its first F-15 Eagle air superiority
fighter in 1974. Subsequently, the F-15 evolved to
encompass more roles, most notably with the deployment
of the F-15E Strike Eagle in 1989. The F-15E added
substantial air-to-ground capability, including a second
cockpit for a weapons systems operator. The Air Force has
453 F-15s of all variants, the last of which was ordered in
2001. Since then, F-15s have been continuously produced
for a variety of international customers, including (among
others) Israel, Saudi Arabia, and Japan.
Figure 1. F-15EX Concept
Source: Boeing.
Current F-15s have stronger airframes and more advanced
sensors, processors, and flight control systems than those in
the U.S. fleet. Many also include conformal fuel tanks to
extend range and increase payload. The proposed F-15EX
would be based on the most advanced Eagles, currently
entering production for Qatar, which first flew on April 14,
2020. F-15EXs would add radar and other subsystems
unique to the United States. Boeing says that the F-15EX
would have 70% parts commonality with existing U.S.
F-15s.
Why is the Air Force requesting
F-15EXs?
Air Force officials have offered numerous justifications for
the F-15EX:
The Air Force is engaged in upgrades to its existing
F-15 fleet. While costing more per aircraft than
modernizing legacy F-15s, a new F-15EX would yield
more future life. Replacing the older, 1980s-era F-15Cs
with F-15EX could also enable the Air Force to avoid
the cost of some or all of those upgrades. “The Air
Force has tried to retire its 250 aging F-15Cs and two-
seat F-15Ds over the years due to structural issues with
the aircraft, including most recently in 2017. Now,
instead of paying to upgrade the older aircraft in the
fleet, the Air Force hopes to use that money to buy
Boeing’s F-15EX.”
Buying F-15s, according to the Air Force, is an
economical way of reaching the service’s goals for
fighter fleet size and average age. “Gen. James ‘Mike’
Holmes, head of Air Combat Command, told reporters
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
from an F-15C to an F-35 could be anywhere from 18 to
36 months and would require MILCON and other
attributes that are not in our budget.”
F-15EX procurement helps maintain a competitive
fighter aircraft industrial base. Currently, Boeing and
Lockheed Martin are the prime contractors supplying
fighter jets to the Department of Defense. A National
Defense magazine report stated
After the decision was made to continue with a
mix of fourth- and fifth-generation aircraft,
“the conversation then turned to how are we
