The US Air Force needs to be moving towards a purchase of new F-15X Super Eagles from Boeing. F-15C/Ds that are attached to three active-duty units need to be replaced with the new F-15X, enabling the older Eagles to cascade down to the Air National Guard. This will, in turn, enable the ANG to retire its two-seat F-15Ds that retain original AN/APG-63(v)0 mechanically scanned array radars. The USAF is facing a conundrum of whether to embark on expensive upgrades that are needed for its existing F-15C/Ds, or purchase new aircraft. Last week Lt Gen Arnold Bunch, the USAF’s top acquisition officer, said that the USAF will seek to add new Super Eagles in the FY2020 defence budget in order to replace the oldest F-15C/Ds still in service. This is linked to meeting the new National Défense Strategy, with increased F-35 purchase rates unable to meet the USAF’s time-critical demand for expansion. Senior USAF officials want to tap into the Advanced F-15 that has been developed for Saudi Arabia and Qatar. The F-15X will likely be offered as single-seat F-15CX and two-seat F-15EX versions of these variants, and is available in relatively short order from Boeing. Keeping the F-15 production line active in St Louis means the US and the allies doesn’t become overly reliant on Lockheed Martin. In addition, the F-15X is likely to be sold as a spend-to-save — a new Eagle runs out at the $100 million mark according to previous delivery costs, however the new USAF F-15X is likely to run out far cheaper at $75 or $80 million per aircraft. Officials have made no secret that the suite of upgrades required to keep old F-15C/D Eagles credible is almost prohibitively expensive. New weapons racks, new wings, upgraded cockpit and a new electronic warfare self-protection system to mention a few. Even throwing a huge upgrade package at the F-15C/D would still see the aircraft falling short of the capabilities of the Advanced F-15, which features a Digital Flight Control System. This is critical in that it opens up wing stations 1 and 9, enabling expanded weapons carriage — a significant factor for the USAF as it seeks to up-arm it’s Eagles to act as ‘weapons trucks’ to complement its stealthy fifth-gen fighters. It's no secret how old the current F-15C/Ds are and that at some point in time they'll need replaced. The need is based on the national security strategy and how that trickles down to DoD (Department of Defence) requirements to fill war plans to meet that strategy. Since most if that is classified, it's tough to define the DoD need in an unclassified forum. There is no good ratio for fifth-to-fourth generation replacements seeing as how the USAF never really been forced to use their fifth generation assets against a near peer in real combat. While the pilots can train to many different scenarios and simulate threat aircraft in large force exercises such as "Red Flag", it won't completely validate the force structure until those capabilities are used in a real conflict. The USAF didn't buy enough F-22A Raptors to fill the need for air superiority and that's why you've seen them extend the life of the existing F-15C/D models. Given that the F-35 production line is still opened and in fact the F-35 program needs to be cancelled. The question becomes one of cost compared to an alternate capability like the new F-15 from Boeing. It's my opinion that, for several reasons, it's beneficial to have a new modernised fourth generation fighter assets. I add that it also comes down to an ability to support those assets in service, the need to procure and/or sustain larger fourth generation aircraft fleets being a major factor in the need for overall mass. You can see the benefit of retaining several wings of fourth generation fighters and the options that gives combatant commanders. I believe it's one of the main reasons why the F-15C/D and the older type the A-10C Warthog are still so valuable and haven't been retired yet. The sixth generation PCA (Penetrate Counter Air) fighter is still years away and likely will not be purchased in sufficient numbers to address all the force structure requirements that future national security strategies could require. If I was Boeing, I'd take the F-15QA, make a single-seat F-15CX and also make a two-seat F-15EX versions of these variants, call it the F-15X, offer it up as cheap as possible to the USAF and to the new and existing customers and see what happens.

Re: Complementary Airpower: The Case for the F-15X

One clear solution to mitigate these challenges is the immediate introduction of Boeing’s F-15X into the current fighter force. While DoD was focused on getting the F-35 IOC and increasing inventory, Boeing continued to improve the capability and capacity of one of the most successful fighters in history. The F-15X Super Eagle is a 4++ gen fighter that will significantly complement the capabilities of the current fighter force with better sensors, more weapons capacity, reliable data links, and extended range. In addition, the F-15X will provide relief to the 5th gen fleet from missions that do not require stealth but require advanced sensors, weapons, datalinks, and range to optimise effectiveness and survivability. The F-15X is the common-sense answer to the limitations of both the current and future fighter force. Here is my take? The F-35 has morphed. In order for the plane to survive they've had to sell its features as being high end. That and the fact that it's taken so long to develop and is NOT going to meet the promise of being as affordable as current fighters has led to a return to the past. A high-low mix. The funny thing is that the USAF envisioned the F-35 as it's low end. Not anymore. The reality now is that the high end portion of the mix is the F-22 and F-35. The low end will be so called 4th gen fighters. The F-15X will certainly fill that bill. But what about Lockheed Martin? The US can't have that manufacturer (despite their bad behaviour with their thana marketing strategy) go down. So what do we do? I'm betting that we will see a US version of the F-16E/F Block 70/72 (F-21) for India to fill a portion of the low end mix along with the F-15X. I've taken heat for my claim that the F-35 is headed toward a death spiral. Fair enough. But one thing is becoming apparent. You can probably scratch at least a 300-500 of them off the procurement list. The F-15X is a thing and it's coming. That alone means fewer F-35A's for the USAF.

For more information - https://www.realcleardefense.com/articles/2019/02/21/complementary_airpower_the_case_for_the_f-15x_114201.html?utm_source=RC+Defense+Morning+Recon&utm_campaign=399a9f5c52-EMAIL_CAMPAIGN_2019_02_20_07_42&utm_medium=email&utm_term=0_694f73a8dc-399a9f5c52-85340453

The F-35 is going to be a long work in progress considering its laborious upgrade process, its current limited weapons capability, its enormous high CPFH and maintenance needs, and known reconstruction costs.

There are clear & present advantages of buying new advanced F-15s;

#1 - Foreign buyers have paid for all of the development costs for the Advanced F-15 models,

#2 - Based on #1 Boeing has developed a much long-lifespan and much-lower CPFH, as well as improved capabilities, for the new F-15 models,

#3 - The production line is hot with more oversees orders ongoing thereby economies of scale have lowered per unit prices,

#4 - The Advanced F-15CX/EX has clear performance advantages that the F-35 can't match,

#5 - Transition to a new model by existing F-15 squadrons would be much easier,

#6 - Rumours are that Boeing can offer the Advanced F-15CX/EX at a cost below the F-35,

#7 - The F-15CX/EX can complement existing F-22s and F-35s as a Force multiplier, and

#8- The legacy F-15C/D/E fleet is tired from massive amounts of use the last 30+ yrs.

If I was the USAF I would ask Boeing for two options;

#1 - fixed cost contract to replace the entire F-15C/D fleet, and

#2 - fixed cost contract to replace F-15C/Ds plus the entire F-15E fleet. Especially since two models (single & two seat) are being talked about.

With option #2 - Boeing could lower costs more due to a BIG one time production contract, and ramp production up based on a big contract.

Adding some additional airframes to transfer the E/A-18G ECM capabilities to an F-15 equivalent is a smart suggestion, especially since stealthy F-22s and F-35s might need some stand-off ECM help since their advantages will likely be degraded as time goes on.

Lastly, engine wise the USAF should consider is the GE Aviation General Electric F110-GE-132 since its' fully qualified, in use by F-16E/Fs, and having extra power is always handy.

While both F-22s and F-35s could operate as "disruptor" and 1st day forces, they would also serve as CNC nodes to allow the advanced F-15s to provide the much higher weapons load/capability that the F-22 and F-35 can't.

Boeing might have an even better suggestion unmanned fighters along with 5th and 4th Generation fighters. Or even a massive aircraft like a C-17 to manage not one or two unmanned fighters but dozens could you imagine the chaos the would cause in the air. Don't think both the Russians and Chinese are not thinking about that time to get smarter with our weapons

Two concerns seem to be the focus of this F-15X debate: cost and Fourth-Generation Plus fighter performance.
The USAF needs the F-15CX and F-15EX as not everything requires stealth or expensive high maintenance and flight hours like the F-35. If the F-22s and F-35s are grounded for some reason, it’s the F-15Xs that will “Hold the CONUS line of defense” for the USA.
Furthermore, two-seats, two-engines, Mach 2.5, 22 AAMs, 70,000 feet ceiling, and specs that the F-35 cannot match make it attractive. A two-seater can control the Boeing Australia unmanned wingman drone being proposed. F-15Xs may not be the best plane in the sky, but it sure is mature and proven enough to trounce the analog/semi-digital F-15Cs and F-16Cs that are now NORAD CONUS air defense.

The F-35 program is $1.2 trillion. If the US buys all 2500 planned aircraft the unit cost per plane will be approx. $490,000,000 per aircraft.
Simple math.