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Wednesday, February 18, 2015

America's Sixth Generation Fighters: The F-X and F/A-XX - III

Image 13: Early Lockheed Martin F-X concept. Image Credit: Lockheed Martin, 2012.  

The primary role of the aircraft produced as a result of the F-X program will be air superiority as a replacement for the F-22 (Majumdar, 2014). The Air Force has been comparatively more bullish on the future of adaptive cycle engines, stealth, and UAVs when compared to the Navy. The greater emphasis placed on air superiority over a deep strike role, as described in the F/A-XX section, will greatly impact the F-X's design as described by Air Force and defense industry officials interviewed by Dave Majumdar:
“'I would expect our requirements to be a lot different from the Navy’s,' Col. Tom Coglitore, who heads Air Combat Command’s Air Superiority Core Function Team and the F-X program, told the trade journal Aviation Week in its Oct. 13 issue. 'Our system of systems would be more offensively minded and operate in more difficult and highly contested areas of operation than the areas the Navy will likely be operating in'...The Navy may need to be content with ceding the uber-air dominance mission to the USAF due to the geometric constraints of their ‘mobile airbases’"
Air Force officials consistently uses the term "systems of systems" (SOS) when describing their vision for a new a sixth generation aircraft. General Carlisle explained the Air Force is reviewing the prospect of making significant changes to communications, capabilities from space, standoff and stand in options under a comprehensive assessment of air superiority in 2030 (Butler, 2015). Similarly,  Lt. Gen. James Holmes said, "[ the Air Force] not want to jump straight to the idea of a sixth-generation fighter". Given the service's aforementioned stance on the future of UAVs, the author surmises the air force plans to integrate UAVs with manned sixth generation aircraft in future air-to-air missions. However, the service has yet to release R&D or procurement plans, at least in the public domain, for a UCAV that would act as a force multiplier for sixth generation aircraft. The canceled MQ-X program likely have produced a UCAV with similar capabilities required to act as a force multipler but the program was canceled in 2012. The General Atomics Avenger did not meet MQ-X requirements (Axe, 2013).

Another possibility implied by SOS would be to integrate the LRS-B with the F-X. The LRS-B would be loaded with stand-off range air-to-air missiles and the F-X with a high power GaN AESA radar which would provide targeting information; the LRS-B has also frequently been referred to as a SOS or "family of systems". The LRS-B's bomb bay will accommodate at least 30,000 pounds in ordinance and its extensive signature reduction methods coupled with extended range air-to-air missiles would reduce risk to the aircraft (Hodge, 2013). It is also possible the SOS term refers to Air Force plans to integrate the F-X with ISR assets like the RQ-180 to perform electronic attack and suppression of enemy air defense (SEAD) missions which will be discussed later. Regardless of SOS, the physical F-X platform will rely upon its variable cycle engines to overcome the "tyranny of distance" between US facilities in the Pacific and they likely area of operations in the Western-Pacific. 

Image 14: Key US air bases with respect to their distance from the Taiwanese Strait. Image Credit: RAND, 2008. 

The Air Force's sixth generation air superiority fighter will likely be based from Andersen air force base at Guam which is 1,500 nautical miles from China's mainland. Air bases closer than 1,500 nautical miles will be subject to cluster munition strikes from Chinese ballistic missiles. The limited number of hardened aircraft shelters and exposed fuel storage depots at these locations would entail a high risk to US aircraft (RAND, 2008). The extended range from Guam to mainland China will put a heavy strain on tanker aircraft supporting fifth generation aircraft. For example, F-22s with a full load of air-to-air weapons would have to refuel six times (to destination and return) with a total fuel consumption rate of 2.6 million gallons per day to support 120 F-22s with 69 KC-135s. Raptors based at Guam would only be able to conduct 1.15 combat air patrol sorties per day meaning China would maintain a 10:1 numerical advantage at any given time over the Taiwanese strait with Andersen based aircraft and 3:1 from Kadena (RAND, 2008). The F-X will be able to more easily operate from Andersen given its variable cycle engines and will be better suited to face large numbers of J-20s in the 2030s than its fifth generation counterparts. Futhermore, the F-X will work alongside the LRS-B and RQ-180 in SEAD and Destruction of Enemy Air Defense (DEAD) missions.

As a result of the increment 3.1 upgrades, the F-22 is among the most capable SEAD/DEAD platforms in the USAF and it is likely the F-X will be tasked with similar roles. Working in conjunction with the RQ-180 and LRS-B, the F-X will play a vital role in disabling VHF radars, C2 nodes, missile batteries, and DF-21 launch sites within China's integrated air defense system (IADS). The addition of powerful GaN based electronic warfare systems, broadband stealth, and energy weapons will allow the F-X to support fifth generation assets to operate further within the A2/AD zone than would otherwise possible. In summary, the F-X concept and design characteristics are highly relevant to the expected threat environment of the late 2030s to 2040s.

Key Characteristics, Roles, and Missions F/A-XX

Image 15: Boeing F/A-XX concept 

Navy official have released few details as to the role and capabilities of the F/A-XX. Navy Rear Adm. Mike Manazir vaguely described the F/A-XX,
"You have to have something that carries missiles, you have to have something that has enough power and cooling for directed energy weapons and you have to have something that has a weapons system that can sense the smallest radar cross-section targets...We’re looking to replace the F/A-18E/F with an understanding already of what the F-35C has brought to the air wing, what the UCLASS mission set is,"
Adm. Mike Manazir indicated that as a replacement for the F/A-18E/F, the F/A-XX will focus on a strike role rather than air superiority which is the F-35C's role under NIFC-CA (Tucker, 2015). Similarly, changes made to the UCLASS program requirements underscore the emphasis of the F/A-XX as a deep strike platform. UCLASS was conceived as a 2,000 nautical mile range low observable platform which would enable carriers to operate outside of enemy A2/AD weapons employment range. However, the Navy altered its requirements for UCLASS from a low observable strike platform to a limited ISR platform in order to justify the role of the F/A-XX:
"The striking power and stealth of the U.S. Navy’s Unmanned Carrier Launched Airborne Surveillance and Strike (UCLASS) concept was reduced to protect the role of the service’s next-generation of manned fighters, USNI News has learned. In particular, the change in UCLASS from a deep strike stealthy penetrator into the current lightly armed intelligence, surveillance and reconnaissance (ISR) focused aircraft was — in large part — to preserve a manned version of the F/A-XX replacement for the Boeing F/A-18E/F Super Hornet, several Navy, Pentagon and industry sources confirmed to USNI News. Industry, Pentagon and Navy sources outlined a, 'bureaucratic and cultural resistance to the introduction of unmanned aircraft onto the carrier.'" - Dave Majumdar and Sam LaGrone, 2014 
The Navy's decision to delay the acquisition of a high-end stealthy carrier strike platform is, in the author's view, shortsighted. Depending upon how the fight for UCLASS program requirements unfold, the role of the F/A-XX may be subject to change. Deputy Secretary of Defense Robert Work currently chairs the Defense Acquisitions Board and he has been a longtime supporter of a high end UCLASS (he advocated for a high-end UCLASS as early as 2007 while working for the Center for Strategic and Budgetary Assessments). Furthermore, Congressional support for a high-end UCLASS remains strong with the backing of chairman of the House subcommittee on Seapower Randy Forbes. The Navy should embrace UCLASS as its low observable strike platform and subsequently adjust the F/A-XX to be geared towards its premier carrier based long range interceptor as a fleet defense asset with both robust sea control and offensive anti-air warfare capabilities similar to how the F-14 was utilized under its "Outer Air Battle" concept in the Cold War.

Image 16: F-14A fires a long range AIM-54 Phoenix missile

Several US Navy concepts developed during the 1980s were in response to the Soviet's use of sea denial platforms to keep the US Navy from being able to conduct transatlantic resupply operations (Tangredi, pgs. 36-38). With the rise of China as a near military competitor to the United States whose military will employ A2/AD methods, many of the Cold War concepts developed to protect US carrier battle groups are becoming increasingly relevant. Under the Outer Air Battle concept, F-14s would be guided by E-2Cs to intercept Soviet Tu-22 "Backfire" and Tu-95 "Bear" bombers at extended ranges away from the carrier group (Clark, 2014). Soviet bombers employed too many anti-ship cruise missiles (ASCMs) for individual missile interceptors to be cost effective but the combination of the F-14 armed with its 100 nautical mile range AIM-54 and the E-2C enabled the Navy to, "shoot the archer before he shoots his arrows". By destroying the launch platform of the ASCMs before they can fire at the carrier group, rather than targeting individual ASCMs, the F-14 would have been able to cost effectively protect the carrier battle group from air based threats. The basics of Outer Air Battle could be reimplemented with the F/A-XX, E2-D, and a yet to be developed long range air-to-air missile. This future assortment of systems could target Chinese and Russian air launched ASCM platforms at extended ranges as well as A2/AD enablers such as enemy Command and Control (C2) and ISR assets. For example, by destroying Chinese UAVs like the Chengdu Tian Yi and other ISR assets, the DF-21 "carrier killer" would be unable to receive mid-course guidance updates required to successfully hit American carriers.

As for why a new platform is needed to fulfill this fleet defense role rather than the F-35C, the variable cycle engines on the F/A-XX and presumably larger fuel capacity would grant it the ability to perform long duration combat air patrols at extended ranges further from the carrier strike group than the F-35C. Furthermore, the addition of a directed energy weapon on the F/A-XX would enable the aircraft to intercept any ASCMs launched against the carrier group which would subsequently reduce the strain on the limited number ship based interceptors like the SM-6 and evolved sea sparrow missile. Ideally, the F/A-XX would also be an exceedingly capable air dominance platform similar to the terminated A/F-X concept in order to enforce sea control and conduct offensive anti-air warfare missions.

Image 17: Lockheed A/F-X concept. The A/F-X program would have produced a twin engine low observable carrier based air superiority fighter second only to the F-22. The A/F-X would have replaced the A6 Intruder, F-14, F-15E, and F-111.

Sea control is the prerequisite to power projection operations which carriers are often associated with. The Navy defines sea control as the deployment of naval and air forces with the intent of establishing local military superiority, defending critical sea lines of communication, destruction of enemy naval vessels, and suppression of enemy sea commerce (Naval Operations Concept, pg. 52). Carrier based fighter's air-to-air capabilities would perform vital roles assisting surface action groups achieve sea control such as protecting surface action groups, tanker aircraft, ISR assets, and Airborne Early Warning aircraft. Jon Solomon further explains how carrier air wings would facilitate sea control in tandem with surface combatants:
"...carrier-based fighters—supported by battleforce-organic Airborne Early Warning (AEW) and aerial refueling assets, with augmentation by land-based AEW and tanker aircraft as possible—might screen SAGs throughout their contested zone missions. Carrier-based fighters might likewise be sortied forward if a SAG makes heavy contact with adversary forces, or be used to cover an ordnance-depleted SAG’s retirement from the contested zone. The same would be true for providing similar support to maritime forces operating at the ‘frontline’ at the beginning of a war. Fighters based on land within the contested zone could also render this support, but because their doing so would be predicated on their basing’s survivability and logistical lines of communications’ defensibility, carrier-based fighter support remains a necessary hedge within operational plans." - 2014 
As the F-X section describes, sixth generation aircraft will be needed when the mass deployment of Russian and Chinese fifth generation aircraft would severely reduce US exchange rates; the reduced US exchange rates in conjunction with the adversary's in thetare numerical advantage limits the prospect of the US being able to establish air superiority. As an author, I have been a staunch supporter of the F-35 program and I have often sought to defend its substantial air to air capabilities in the midst of mostly unfounded criticism. With a capable pilot, the F-35 is able to engage foreign stealth aircraft such as the J-20 and PAK FA as discussed ad nauseam in many of my articles. However, the F/A-XX will serve in the 2035-2050s time frame under a strategic environment where US competitors are likely to obtain both a numerical advantage and reduce the existing performance disparity between their fifth generation aircraft and the F-22 and F-35. The carrier air wing of 2030 requires a high-end air dominance platform to complement the F-35C strike fighter in order for the carrier to remain relevant in extremely hostile A2/AD environments. The United States' will have to respond to the aforementioned developments with higher quality air superiority aircraft given the finite space of the carrier flight deck in conjunction with new concepts and unmanned systems.

Image 18: Carrier air wing of the 2020s. Image Credit: Center for New American Security, 2014

Future Ford-class and upgraded Nimitz-class aircraft carriers will host only 44 strike fighters (20 F-35Cs and 24 F/A-18E/Fs) and possibly 6 UCLASS with limited strike capability under current procurement plans. In recent conflicts, the US Navy has at most deployed six carrier strike groups at any one time including surged units (Erdossy, 2012). Thus, at best the Navy could field 264 aircraft that could serve in an air-to-air role (300 with high-end UCLASS as a "missile truck" linked via NIFC-CA) .

The proposed F/A-XX's relationship to the F-35C would be similar to the F-22's complementary role to the F-35A in the Air Force or how the F-14 complemented the legacy F/A-18A/B Hornet in older carrier air wings. Without a high-end air superiority fighter, the carrier air wing will become less relevant to great power conflicts. During the Cold War, well armed and highly maneuverable F-14s provided the carrier group with an effective  air superiority and fleet defense capability. The F-14 was replaced in 2006 by the F/A-18E/F Super Hornet which was designed and built after the collapse of the Soviet Union when the US held uncontested dominion of the seas and the threat of a major great power conflict had subsided. Ideally, the F/A-XX should be thought of as an opportunity to replace the F-14 with A/F-X elements (such as low observability and supermaneuverability) rather than a replacement for the F/A-18E/F.

Upgrading the F-35

Image 19: F-35

Both the Air Force and Navy will examine the prospect of significantly upgrading the F-35 (and F-22) with the aforementioned sixth generation capabilities such as directed energy weapons and variable cycle engines as part of their analysis of alternatives (AOA) to building a new sixth generation fighter. However, Air Force and Navy officials speaking with Dave  Majumdar were not confident the F-35 will be upgraded to preform air dominance missions:
"The Navy will start its formal AOA in 2015 while the Air Force’s analysis will start a little later—in about a year and a half from now [December 2014] .The Air Force hopes to enter into a technology development phase in 2018...It will likely be one of the alternatives in the Analysis of Alternatives,” said a senior Air Force official...The Air Force official added that another alternative will be to modify and upgrade the tiny 186 aircraft-strong F-22 Raptor fleet. 'Modifying the Raptor will be an option too,' he said. 'I doubt either the F-22 or F-35 will win.’" -  Majumdar , 2014 
A host of new weapons and planned upgrades such as Lockheed Martin's CUDA, the AIM-9X Block III (pending its possible cancellation in the Navy's FY 2016 budget request), and Block 4 upgrades to increase the weapons bay capacity for internally carried AIM-120Ds to six paired with new sixth generation technologies would make the F-35 significantly more effective in an air-to-air role. Depending upon the cost of the individual upgrades, both the Navy and Air Force should consider adding some sixth generation technologies into their F-35 fleets in the late 2020s to early 2030s. For example, Block 6 improvements indicate the F-35 will receive a propulsion upgrade and the F-35 will likely be the first operational fighter aircraft with an adaptive cycle engine. However, upgrading the F-35 in lieu of developing a sixth generation fighter is not a plausible option unless the Pentagon is willing to facilitate further consolidation of the military aerospace industry which is likely to have detrimental effects of the competitiveness of future contracts. Ultimately the decision to significantly upgrade the F-35 will depend upon fiscal resources and the next presidential administration's management of the DoD.


In summary, the natural progression of threats from Russia and China necessitates a proactive US response to regain a technological advantage. The natural progression of threats does not reflect poorly on either the development of the F-22 or F-35 which are necessary programs the Air Force and Navy must sustain. Both fifth generation aircraft will be able to provide robust air-to-air capabilities over the next decade but as VHF systems evolve electronic warfare support will become increasingly important in the 2030s. As the F-X and F/A-XX programs progress, the DoD must be cognizant of the health of the US defense industrial base with respect to consolidation and the deeply unnerving bureaucratic/institutional constraints that currently inhibit the development of Naval UAV systems. Furthermore, the Navy should not cede the high-end air dominance mission to the Air Force and should subsequently re-adjust its F/A-XX concept to provide a more robust fleet defense and air-to-air capability. Lastly, upgrading both the F-22 and F-35 with sixth generation technology without building new sixth generation aircraft is not a plausible option. The addition of directed energy weapons, variable cycle engines, and GaN avionics would greatly increase the capabilities of fifth generation aircraft but such upgrades would be dependent on the fiscal environment of the late 2020s to 2030s.

Author's Note: Feel free to let me know if you have any comments, concerns, or suggestions.

Part I - The Need for 6th Gen. and 2030 A2/AD


  1. is there any recommendations on stealth? Or the current level of stealthiness of F-22 is enough?

    1. Because stealth is largely a consequence of air frame shape (one Lockheed Martin engineer said 80% shape 20% materials) there isn't much that can be done to reduce the F-22's potential vulnerability to VHF systems. China and Russia will have to continue to invest in VHF technology for another decade or more before it becomes a serous threat due to the fact VHF systems can't provide quality targeting information (for now). Before the 2030s, the best the Chinese and Russians will get is likely an early warning system that is capable of detecting the F-22 and F-35 but not engaging them. Other assets, like fighter aircraft, would be sent to intercept the F-22 and F-35. At the present, Russia and China field VHF systems in very limited quantities so the bottom line is the F-22 will continue to be effective for at least another decade in its SEAD/DEAD role. But, the threat is real enough that its time to invest in broadband stealth that can defeat VHF systems.

  2. It is very gratifying to finally see someone actually praising the F-14 and the "old" outer air battle mission. For far too long, I've been reading, and hearing about how the Tomcat and the AIM-54 were relics of a by-gone era. I do hope the proposed F/A-XX does share the same aerodynamic characteristics of the F-14, such as excellent range, speed, and cross sector agility to name a few. I am especially glad to see the Navy is pushing for their own requirements to be met. Outstanding article, keep it up!

    1. Thank you! I've been realizing a lot lately that many Cold War concepts are increasingly relevant today and I hadn't previous heard of Outer Air Battle (OAB) until Bryan Clark released his new Offensive Sea Control concept which takes inspiration from OAB. It is unfortunate the DoD cancelled the next generation missile, joint dual role air dominance missile, and AIM-152 programs. While the AIM-120D is a great missile and its 100 nm range is above average, both the USAF and USN need a new longer range missile in the 2030s. Hopefully the Navy will change their F/A-XX requirements to be more like the Tomcat and A/F-X but I realistically don't know how likely that is going to be, as for now its much less ambitious than the F-X.