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Lockheed Martin F-35 Lightning II
Lockheed Martin F-35 Lightning II
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The Lockheed Martin F-35 Lightning II is an American family of single-seat, single-engine, supersonic stealth strike fighters. A multirole combat aircraft designed for both air superiority and strike missions, it also has electronic warfare and intelligence, surveillance, and reconnaissance capabilities. Lockheed Martin is the prime F-35 contractor with principal partners Northrop Grumman and BAE Systems. The aircraft has three main variants: the conventional takeoff and landing (CTOL) F-35A, the short take-off and vertical-landing (STOVL) F-35B, and the carrier variant (CV) catapult-assisted take-off but arrested recovery (CATOBAR) F-35C.

Key Information

The aircraft descends from the Lockheed Martin X-35, which in 2001 beat the Boeing X-32 to win the Joint Strike Fighter (JSF) program intended to replace the F-16 Fighting Falcon, F/A-18 Hornet, and the McDonnell Douglas AV-8B Harrier II "jump jet", among others. Its development is primarily funded by the United States, with additional funding from program partner countries from the North Atlantic Treaty Organization (NATO) and close U.S. allies, including Australia, Canada, Denmark, Italy, the Netherlands, Norway, the United Kingdom, and formerly Turkey.[5][6][7] Several other countries have also ordered, or are considering ordering, the aircraft. The program has drawn criticism for its unprecedented size, complexity, ballooning costs, and delayed deliveries.[8][N 1] The decision to start manufacturing the aircraft while it was still in development and testing led to expensive design changes and retrofits.[10][11] As of July 2024, the average flyaway costs per plane are: US$82.5 million for the F-35A, $109 million for the F-35B, and $102.1 million for the F-35C.[12]

The F-35 first flew in 2006; its variants entered U.S. service in July 2015 (Marine Corps F-35B), August 2016 (Air Force F-35A), and February 2019 (Navy F-35C).[2][3][4] The aircraft first saw combat in 2018, during Israeli Air Force attacks on Syria.[13] The F-35 has since been used in combat by the U.S. in Afghanistan, Iran, Iraq, and Yemen; by Israel in Gaza, Iran, Iraq, Lebanon, and Yemen; and by the UK in Iraq and Syria. F-35As contribute to US nuclear forward deployment in European NATO countries. The U.S. plans to buy 2,456 F-35s through 2044, which will represent the bulk of its crewed fixed-wing tactical aviation for several decades; the aircraft is to be a cornerstone of NATO and U.S.-allied air power and operate until 2070.[14][15][16]

Development

[edit]

Program origins

[edit]

The F-35 was the product of the Joint Strike Fighter (JSF) program, which was the merger of various combat aircraft programs from the 1980s and 1990s. One progenitor program was the Defense Advanced Research Projects Agency (DARPA) Advanced Short Take-Off/Vertical Landing (ASTOVL) which ran from 1983 to 1994; ASTOVL aimed to develop a Harrier jump jet replacement for the U.S. Marine Corps (USMC) and the UK Royal Navy. Under one of ASTOVL's classified programs, the Supersonic STOVL Fighter (SSF), Lockheed's Skunk Works conducted research for a stealthy supersonic STOVL fighter intended for both U.S. Air Force (USAF) and USMC; among key STOVL technologies explored was the shaft-driven lift fan (SDLF) system. Lockheed's concept was a single-engine canard delta aircraft weighing about 24,000 lb (11,000 kg) empty. ASTOVL was rechristened as the Common Affordable Lightweight Fighter (CALF) in 1993 and involved Lockheed, McDonnell Douglas, and Boeing.[17][18]

The end of the Cold War and the collapse of the Soviet Union in 1991 caused considerable reductions in Department of Defense (DoD) spending and subsequent restructuring. In 1993, the Joint Advanced Strike Technology (JAST) program emerged following the cancellation of the USAF's Multi-Role Fighter (MRF) and U.S. Navy's (USN) Advanced Attack/Fighter (A/F-X) programs. MRF, a program for a relatively affordable F-16 Fighting Falcon replacement, was scaled back and delayed due to post–Cold War defense posture easing F-16 fleet usage and thus extending its service life as well as increasing budget pressure from the Lockheed Martin F-22 Advanced Tactical Fighter (ATF) program. The A/F-X, initially known as the Advanced-Attack (A-X), began in 1991 as the USN's follow-on to the Advanced Tactical Aircraft (ATA) program for an Grumman A-6 Intruder replacement; the ATA's resulting McDonnell Douglas A-12 Avenger II had been canceled due to technical problems and cost overruns in 1991. In the same year, the termination of the Naval Advanced Tactical Fighter (NATF), a naval development of USAF's ATF program to replace the Grumman F-14 Tomcat, resulted in additional fighter capability being added to A-X, which was then renamed A/F-X. Amid increased budget pressure, the DoD's Bottom-Up Review (BUR) in September 1993 announced MRF's and A/F-X's cancellations, with applicable experience brought to the emerging JAST program.[18] JAST was not meant to develop a new aircraft, but rather to develop requirements, mature technologies, and demonstrate concepts for advanced strike warfare.[19]

As JAST progressed, the need for concept demonstrator aircraft by 1996 emerged, which would coincide with the full-scale flight demonstrator phase of ASTOVL/CALF. Because the ASTOVL/CALF concept appeared to align with the JAST charter, the two programs were eventually merged in 1994 under the JAST name, with the program now serving the USAF, USMC, and USN.[19] JAST was subsequently renamed to Joint Strike Fighter (JSF) in 1995, with STOVL submissions by McDonnell Douglas, Northrop Grumman, Lockheed Martin,[N 2] and Boeing. The JSF was expected to eventually replace large numbers of multi-role and strike fighters in the inventories of the US and its allies, including the Harrier, F-16, F/A-18, Fairchild A-10 Thunderbolt II, and Lockheed F-117 Nighthawk.[20]

International participation is a key aspect of the JSF program, starting with United Kingdom participation in the ASTOVL program. Many international partners requiring modernization of their air forces were interested in the JSF. The United Kingdom joined JAST/JSF as a founding member in 1995 and thus became the only Tier 1 partner of the JSF program;[21] Italy, the Netherlands, Denmark, Norway, Canada, Australia, and Turkey joined the program during the Concept Demonstration Phase (CDP), with Italy and the Netherlands being Tier 2 partners and the rest Tier 3. Consequently, the aircraft was developed in cooperation with international partners and available for export.[22]

JSF competition

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Boeing and Lockheed Martin were selected in early 1997 for CDP, with their concept demonstrator aircraft designated X-32 and X-35 respectively; the McDonnell Douglas team was eliminated and Northrop Grumman and British Aerospace joined the Lockheed Martin team. Each firm would produce two prototype air vehicles to demonstrate conventional takeoff and landing (CTOL), carrier takeoff and landing (CV), and STOVL.[N 3] Lockheed Martin's design would make use of the work on the SDLF system conducted under the ASTOVL/CALF program. The key aspect of the X-35 that enabled STOVL operation, the SDLF system consists of the lift fan in the forward center fuselage that could be activated by engaging a clutch that connects the driveshaft to the turbines and thus augmenting the thrust from the engine's swivel nozzle. Research from prior aircraft incorporating similar systems, such as the Convair Model 200,[N 4] Rockwell XFV-12, and Yakovlev Yak-141, were also taken into consideration.[24][25][26] By contrast, Boeing's X-32 employed a direct lift system that the augmented turbofan would be reconfigured to when engaging in STOVL operation.

X-35B flying over Edwards Air Force Base

Lockheed Martin's commonality strategy was to replace the STOVL variant's SDLF with a fuel tank and the aft swivel nozzle with a two-dimensional thrust vectoring nozzle for the CTOL variant.[N 5] STOVL operation is made possible through a patented shaft-driven LiftFan propulsion system.[27] This would enable identical aerodynamic configuration for the STOVL and CTOL variants, while the CV variant would have an enlarged wing to reduce landing speed for carrier recovery. Due to aerodynamic characteristics and carrier recovery requirements from the JAST merger, the design configuration settled on a conventional tail compared to the canard delta design from the ASTOVL/CALF; notably, the conventional tail configuration offers much lower risk for carrier recovery compared to the ASTOVL/CALF canard configuration, which was designed without carrier compatibility in mind. This enabled greater commonality between all three variants, as the commonality goal was important at this design stage.[28] Lockheed Martin's prototypes would consist of the X-35A for demonstrating CTOL before converting it to the X-35B for STOVL demonstration and the larger-winged X-35C for CV compatibility demonstration.[29]

The X-35A first flew on 24 October 2000 and conducted flight tests for subsonic and supersonic flying qualities, handling, range, and maneuver performance.[30] After 28 flights, the aircraft was then converted into the X-35B for STOVL testing, with key changes including the addition of the SDLF, the three-bearing swivel module (3BSM), and roll-control ducts. The X-35B would successfully demonstrate the SDLF system by performing stable hover, vertical landing, and short takeoff in less than 500 ft (150 m).[28][31] The X-35C first flew on 16 December 2000 and conducted field landing carrier practice tests.[30]

On 26 October 2001, Lockheed Martin was declared the winner and was awarded the System Development and Demonstration (SDD) contract; Pratt & Whitney was separately awarded a development contract for the F135 engine for the JSF.[32] The F-35 designation, which was out of sequence with standard DoD numbering, was allegedly determined on the spot by program manager Major General Mike Hough; this came as a surprise even to Lockheed Martin, which had expected the F-24 designation for the JSF.[33]

Design and production

[edit]
Engineer handling a metallic scale model of jet fighter in wind-tunnel
An F-35 wind tunnel testing model in 16-foot (5 m) transonic wind tunnel at the Arnold Engineering Development Center

As the JSF program moved into the System Development and Demonstration phase, the X-35 demonstrator design was modified to create the F-35 combat aircraft. The forward fuselage was lengthened by 5 inches (13 cm) to make room for mission avionics, while the horizontal stabilizers were moved 2 inches (5.1 cm) aft to retain balance and control. The diverterless supersonic inlet changed from a four-sided to a three-sided cowl shape and was moved 30 inches (76 cm) aft. The fuselage section was fuller, the top surface raised by 1 inch (2.5 cm) along the centerline and the lower surface bulged to accommodate weapons bays. Following the designation of the X-35 prototypes, the three variants were designated F-35A (CTOL), F-35B (STOVL), and F-35C (CV), all with a design service life of 8,000 hours. Prime contractor Lockheed Martin performs overall systems integration and final assembly and checkout (FACO) at Air Force Plant 4 in Fort Worth, Texas,[N 6] while Northrop Grumman and BAE Systems supply components for mission systems and airframe.[34][35]

Adding the systems of a fighter aircraft added weight. The F-35B gained the most, largely due to a 2003 decision to enlarge the weapons bays for commonality between variants; the total weight growth was reportedly up to 2,200 pounds (1,000 kg), over 8%, causing all STOVL key performance parameter (KPP) thresholds to be missed.[36] In December 2003, the STOVL Weight Attack Team (SWAT) was formed to reduce the weight increase; changes included thinned airframe members, smaller weapons bays and vertical stabilizers, less thrust fed to the roll-post outlets, and redesigning the wing-mate joint, electrical elements, and the airframe immediately aft of the cockpit. The inlet was also revised to accommodate more powerful, greater mass flow engines.[37][38] Many changes from the SWAT effort were applied to all three variants for commonality. By September 2004, these efforts had reduced the F-35B's weight by over 3,000 pounds (1,400 kg), while the F-35A and F-35C were reduced in weight by 2,400 pounds (1,100 kg) and 1,900 pounds (860 kg) respectively.[28][39] The weight reduction work cost $6.2 billion and caused an 18-month delay.[40]

The first F-35A prototype, AA-1, being towed to its inauguration ceremony on 7 July 2006

The first F-35A, designated AA-1, was rolled out at Fort Worth on 19 February 2006 and first flew on 15 December 2006 with chief test pilot Jon S. Beesley at the controls.[N 7][41] In 2006, the F-35 was given the name "Lightning II" after the Lockheed P-38 Lightning of World War II.[42] Some USAF pilots have nicknamed the aircraft "Panther" instead, and other nicknames include "Fat Amy" and "Battle Penguin".[43][44][45]

The aircraft's software was developed as six releases, or Blocks, for SDD. The first two Blocks, 1A and 1B, readied the F-35 for initial pilot training and multi-level security. Block 2A improved the training capabilities, while 2B was the first combat-ready release planned for the USMC's Initial Operating Capability (IOC). Block 3i retains the capabilities of 2B while having new Technology Refresh 2 (TR-2) hardware and was planned for the USAF's IOC. The final release for SDD, Block 3F, would have full flight envelope and all baseline combat capabilities. Alongside software releases, each block also incorporates avionics hardware updates and air vehicle improvements from flight and structural testing.[46] In what is known as "concurrency", some low rate initial production (LRIP) aircraft lots would be delivered in early Block configurations and eventually upgraded to Block 3F once development is complete.[47] After 17,000 flight test hours, the final flight for the SDD phase was completed in April 2018.[48] Like the F-22, the F-35 has been targeted by cyberattacks and technology theft efforts, as well as potential vulnerabilities in the integrity of the supply chain.[49][50][51]

The first F-35C flight sciences aircraft, CF-01, conducts a test flight over Chesapeake Bay in February 2011.

Testing found several major problems: early F-35B airframes were vulnerable to premature cracking,[N 8] the F-35C arrestor hook design was unreliable, fuel tanks were too vulnerable to lightning strikes, the helmet display had problems, and more. Software was repeatedly delayed due to its unprecedented scope and complexity. In 2009, the DoD Joint Estimate Team (JET) estimated that the program was 30 months behind the public schedule.[52][53] In 2011, the program was "re-baselined"; that is, its cost and schedule goals were changed, pushing the IOC from the planned 2010 to July 2015.[54][55] The decision to simultaneously test, fix defects, and begin production was criticized as inefficient; in 2014, Under Secretary of Defense for Acquisition Frank Kendall called it "acquisition malpractice".[56] The three variants shared just 25% of their parts, far below the anticipated commonality of 70%.[57]

The program received considerable criticism for cost overruns and for the total projected lifetime cost, as well as quality management shortcomings by contractors.[58][59] As of August 2023, the program was 80% over budget and 10 years late.[60]

The JSF program was expected to cost about $200 billion for acquisition in base-year 2002 dollars when SDD was awarded in 2001.[61][62] As early as 2005, the Government Accountability Office (GAO) had identified major program risks in cost and schedule.[63] The costly delays strained the relationship between the Pentagon and contractors.[64] By 2017, delays and cost overruns had pushed the F-35 program's expected acquisition costs to $406.5 billion, with total lifetime cost (i.e., to 2070) to $1.5 trillion in then-year dollars which also includes operations and maintenance.[65][66][67] The F-35A's unit cost (not including engine) for LRIP Lot 13 was $79.2 million in base-year 2012 dollars.[68] Delays in development and operational test and evaluation, including integration into the Joint Simulation Environment, pushed full-rate production decision from the end of 2019 to March 2024, although actual production rate had already approached the full rate by 2020; the combined full rate at the Fort Worth, Italy, and Japan FACO plants is 156 aircraft annually.[69][70]

Upgrades and further development

[edit]
Sailors prepare to taxi an F-35C Lightning II on aircraft carrier USS Carl Vinson.

The F-35 is expected to be continually upgraded over its lifetime. The first combat-capable Block 2B configuration, which had basic air-to-air and strike capabilities, was declared ready by the USMC in July 2015.[2] The Block 3F configuration began operational test and evaluation (OT&E) in December 2018 and its completion in late 2023 concluded SDD in March 2024.[71] The F-35 program is also conducting sustainment and upgrade development, with early aircraft from LRIP lot 2 onwards gradually upgraded to the baseline Block 3F standard by 2021.[72][needs update]

With Block 3F as the final build for SDD, the first major upgrade program is Block 4 which began development in 2019 and was initially captured under the Continuous Capability Development and Delivery (C2D2) program. Block 4 is expected to enter service in incremental steps from the late 2020s to early 2030s and integrates additional weapons, including those unique to international customers, improved sensor capabilities including the new AN/APG-85 AESA radar and additional ESM bandwidth, and adds Remotely Operated Video Enhanced Receiver (ROVER) support.[73][74] C2D2 also places greater emphasis on agile software development to enable quicker releases.[75]

The key enabler of Block 4 is Technology Refresh 3 (TR-3) avionics hardware, which consists of new display, core processor, and memory modules to support increased processing requirements, as well as engine upgrade that increases the amount of cooling available to support the additional mission systems. The engine upgrade effort explored both improvements to the F135 as well as significantly more power and efficient adaptive cycle engines. In 2018, General Electric and Pratt & Whitney were awarded contracts to develop adaptive cycle engines for potential application in the F-35,[N 9] and in 2022, the F-35 Adaptive Engine Replacement program was launched to integrate them.[76][77] However, in 2023 the USAF chose an improved F135 under the Engine Core Upgrade (ECU) program over an adaptive cycle engine due to cost as well as concerns over risk of integrating the new engine, initially designed for the F-35A, on the B and C.[78] Difficulties with the new TR-3 hardware, including regression testing, have caused delays to Block 4 as well as a halt in aircraft deliveries from July 2023 to July 2024.[79][80]

In 2023, the GAO raised concerns in two reports that the estimated cost of the Block 4 upgrade has increased from $10.6 billion to $16.5 billion and completion of the upgrade is delayed from 2026 to 2029 the earliest.[81]

Defense contractors have offered upgrades to the F-35 outside of official program contracts. In 2013, Northrop Grumman disclosed its development of a directional infrared countermeasures suite, named Threat Nullification Defensive Resource (ThNDR). The countermeasure system would share the same space as the Distributed Aperture System (DAS) sensors and acts as a laser missile jammer to protect against infrared-homing missiles.[82]

Israel operates a unique subvariant of the F-35A, designated the F-35I, that is designed to better interface with and incorporate Israeli equipment and weapons. The Israeli Air Force also has their own F-35I test aircraft that provides more access to the core avionics to include their own equipment.[83]

Procurement and international participation

[edit]

The United States is the primary customer and financial backer, with planned procurement of 1,763 F-35As for the USAF, 353 F-35Bs and 67 F-35Cs for the USMC, and 273 F-35Cs for the USN.[14] Additionally, the United Kingdom, Italy, the Netherlands, Turkey, Australia, Norway, Denmark and Canada have agreed to contribute US$4.375 billion towards development costs, with the United Kingdom contributing about 10% of the planned development costs as the sole Tier 1 partner.[21] Britain supplies ejector seats, rear fuselage, active interceptor systems, targeting lasers and weapon release cables, mainly through British Aerospace, amounting to 15% of the value of the F-35, and is the largest supplier of spare parts for the jet after the US.[84] The initial plan was that the U.S. and eight major partner countries would acquire over 3,100 F-35s through 2035.[85] The three tiers of international participation generally reflect financial stake in the program, the amount of technology transfer and subcontracts open for bid by national companies, and the order in which countries can obtain production aircraft.[86] Alongside program partner countries, Israel and Singapore have joined as Security Cooperative Participants (SCP).[87][88][89] Sales to SCP and non-partner states, including Belgium, Japan, and South Korea, are made through the Pentagon's Foreign Military Sales program.[7][90] Turkey was removed from the F-35 program in July 2019 over security concerns following its purchase of a Russian S-400 surface-to-air missile system.[91][92][N 10] As of July 2024, the average flyaway costs per plane are: $82.5 million for the F-35A, $109 million for the F-35B, and $102.1 million for the F-35C.[12]

Design

[edit]

Overview

[edit]

The F-35 is a family of single-engine, supersonic, stealth multirole strike fighters.[94] The second fifth-generation fighter to enter US service and the first operational supersonic STOVL stealth fighter, the F-35 emphasizes low observables, advanced avionics and sensor fusion that enable a high level of situational awareness and long range lethality;[95][96][97] the USAF considers the aircraft its primary strike fighter for conducting suppression of enemy air defense (SEAD) and air interdiction missions, owing to the advanced sensors and mission systems.[98]

(From the top) F-35A of the 33rd FW, F-35B of VMFAT-501 and F-35C of VFA-101 near Eglin AFB, 2014
A vortex forms around the body of the aircraft

The F-35 has a wing-tail configuration with two vertical stabilizers canted for stealth. Flight control surfaces include leading-edge flaps, flaperons,[N 11] rudders, and all-moving horizontal tails (stabilators); leading edge root extensions or chines[99] also run forwards to the inlets. The relatively short 35-foot wingspan of the F-35A and F-35B is set by the requirement to fit inside USN amphibious assault ship parking areas and elevators; the F-35C's larger wing is more fuel efficient.[100][101] The fixed diverterless supersonic inlets (DSI) use a bumped compression surface and forward-swept cowl to shed the boundary layer of the forebody away from the inlets, which form a Y-duct for the engine.[102] Structurally, the F-35 drew upon lessons from the F-22; composites comprise 35% of airframe weight, with the majority being bismaleimide and composite epoxy materials as well as some carbon nanotube-reinforced epoxy in later production lots.[103][104][105] The F-35 is considerably heavier than the lightweight fighters it replaces, with the lightest variant having an empty weight of 29,300 lb (13,300 kg); much of the weight can be attributed to the internal weapons bays and the extensive avionics carried.[106] Each F-35 contains about 50 pounds (23 kg) of samarium magnets.[107]

While lacking the kinematic performance of the larger twin-engine F-22, the F-35 is competitive with fourth-generation fighters such as the F-16 and F/A-18, especially when they carry weapons because the F-35's internal weapons bay eliminates drag from external stores.[108] All variants have a top speed of Mach 1.6 (1,220 mph; 1,960 km/h), attainable with full internal payload. The Pratt & Whitney F135 engine gives good subsonic acceleration and energy, with supersonic dash in afterburner. The F-35, while not a "supercruising" aircraft, can fly at Mach 1.2 (913 mph; 1,470 km/h) for a dash of 150 miles (240 km) with afterburners. This ability can be useful in battlefield situations.[109] The large stabilitors, leading edge extensions and flaps, and canted rudders provide excellent high alpha (angle-of-attack) characteristics, with a trimmed alpha of 50°. Relaxed stability and triplex-redundant fly-by-wire controls provide excellent handling qualities and departure resistance.[110][111] Having over double the F-16's internal fuel, the F-35 has a considerably greater combat radius, while stealth also enables a more efficient mission flight profile.[112]

Sensors and avionics

[edit]
The AN/AAQ-40 Electro-Optical Target System (EOTS) under the nose of an F-35A

The F-35's mission systems are among the most complex aspects of the aircraft. The avionics and sensor fusion are designed to improve the pilot's situational awareness and command-and-control capabilities and facilitate network-centric warfare.[94][113] Key sensors include the Northrop Grumman AN/APG-81 active electronically scanned array (AESA) radar, BAE Systems AN/ASQ-239 Barracuda electronic warfare system, Northrop Grumman/Raytheon AN/AAQ-37 Electro-optical Distributed Aperture System (DAS), Lockheed Martin AN/AAQ-40 Electro-Optical Targeting System (EOTS) and Northrop Grumman AN/ASQ-242 Communications, Navigation, and Identification (CNI) suite. The F-35 was designed for its sensors to work together to provide a cohesive image of the local battlespace; for example, the APG-81 radar also acts as a part of the electronic warfare system.[114]

Much of the F-35's software was developed in C and C++ programming languages, while Ada83 code from the F-22 was also used; the Block 3F software has 8.6 million lines of code.[115][116] The Green Hills Software Integrity DO-178B real-time operating system (RTOS) runs on integrated core processors (ICPs); data networking includes the IEEE 1394b and Fibre Channel buses.[117][118] The avionics use commercial off-the-shelf (COTS) components when practical to make upgrades cheaper and more flexible; for example, to enable fleet software upgrades for the software-defined radio (SDR) systems.[119][120][121] The mission systems software, particularly for sensor fusion, was one of the program's most difficult parts and responsible for substantial program delays.[N 12][123][124]

AN/APG-81 AESA radar antenna

The APG-81 radar uses electronic scanning for rapid beam agility and incorporates passive and active air-to-air modes, strike modes, and synthetic aperture radar (SAR) capability, with multiple target track-while-scan at ranges in excess of 80 nmi (150 km). The antenna is tilted backwards for stealth.[125] Complementing the radar is the AAQ-37 DAS: six infrared sensors that can track targets and warn of approaching missiles all around the aircraft; it acts as a situational-awareness infrared search and track (SAIRST) and feeds spherical infrared and night-vision imagery to the helmet visor.[126] The ASQ-239 Barracuda electronic warfare system has ten radio frequency antennas embedded into the edges of the wing and tail for all-aspect radar warning receiver (RWR). It also provides sensor fusion of radio frequency and infrared tracking functions, geolocation threat targeting, and multispectral image countermeasures for self-defense against missiles. The electronic warfare system can detect and jam hostile radars.[127] The AAQ-40 EOTS is mounted behind a faceted low-observable window under the nose and performs laser targeting, forward-looking infrared (FLIR), and long range IRST functions.[128] The ASQ-242 CNI suite uses a half dozen physical links, including the directional Multifunction Advanced Data Link (MADL), for covert CNI functions.[129][130] Information from radio frequency receivers and infrared sensors are combined to form a single tactical picture for the pilot. The all-aspect target direction and identification can be shared via MADL to other platforms without compromising low observability, while Link 16 enables communication with older systems.[131]

The F-35 was designed to accept upgrades to its processors, sensors, and software. Technology Refresh 3, which includes a new core processor and a new cockpit display, is planned for Lot 15 aircraft.[132] Lockheed Martin has offered the Advanced EOTS for the Block 4 configuration; the improved sensor fits into the same area as the baseline EOTS with minimal changes.[133] In June 2018, Lockheed Martin picked Raytheon for improved DAS.[134] The USAF has studied the potential for the F-35 to orchestrate attacks by unmanned combat aerial vehicles (UCAVs) via its sensors and communications equipment.[135]

A new radar called the AN/APG-85 is planned for Block 4 F-35s.[136] According to the JPO, the new radar will be compatible with all three major F-35 variants. However, it is unclear if older aircraft will be retrofitted with the new radar.[136]

Stealth and signatures

[edit]
The sawtooth design on the landing gear door and access panels

Stealth is a key aspect of the F-35's design, and radar cross-section (RCS) is minimized through careful shaping of the airframe and the use of radar-absorbent materials (RAM); visible measures to reduce RCS include alignment of edges and continuous curvature of surfaces, serration of skin panels, and the masking of the engine face and turbine. Additionally, the F-35's diverterless supersonic inlet (DSI) uses a compression bump and forward-swept cowl rather than a splitter gap or bleed system to divert the boundary layer away from the inlet duct, eliminating the diverter cavity and further reducing radar signature.[102][137] The RCS of the F-35 has been characterized as lower than a metal golf ball at certain frequencies and angles; in some conditions, the F-35 compares favorably to the F-22 in stealth.[138][139][140] For maintainability, the F-35's stealth design took lessons from earlier stealth aircraft such as the F-22; the F-35's radar-absorbent fibermat skin is more durable and requires less maintenance than older topcoats.[141] The aircraft also has reduced infrared and visual signatures as well as strict controls of radio frequency emitters to prevent their detection.[142][143][144] The F-35's stealth design is primarily focused on high-frequency X-band wavelengths;[145] low-frequency radars can spot stealthy aircraft due to Rayleigh scattering, but such radars are also conspicuous, susceptible to clutter, and lack precision.[146][147][148] To disguise its RCS, the aircraft can mount four Luneburg lens reflectors.[149] Overseas deployments of the F-35, including the Estonia, Bulgaria, and South Korea, use these radar reflectors to prevent Russian and Chinese intelligence gathering on the true RCS signature. There were concerns that Russian involvement in the Syrian civil war allowed the country to gather true RCS data on Israeli F-35Is flying without reflectors over Lebanon, as well as US F-22s.[150]

Noise from the F-35 caused concerns in residential areas near potential bases for the aircraft, and residents near two such bases—Luke Air Force Base, Arizona, and Eglin Air Force Base (AFB), Florida—requested environmental impact studies in 2008 and 2009 respectively.[151] Although the noise levels, in decibels, were comparable to those of prior fighters such as the F-16, the F-35's sound power is stronger—particularly at lower frequencies.[152] Subsequent surveys and studies have indicated that the noise of the F-35 was not perceptibly different from the F-16 and F/A-18E/F, though the greater low-frequency noise was noticeable for some observers.[153][154][155]

Cockpit

[edit]
F-35 cockpit simulator

The glass cockpit was designed to give the pilot good situational awareness. The main display is a 20-by-8-inch (50 by 20 cm) panoramic touchscreen, which shows flight instruments, stores management, CNI information, and integrated caution and warnings; the pilot can customize the arrangement of the information. Below the main display is a smaller stand-by display.[156] The cockpit has a speech-recognition system developed by Adacel.[157] The F-35 does not have a head-up display; instead, flight and combat information is displayed on the visor of the pilot's helmet in a helmet-mounted display system (HMDS).[158] The one-piece tinted canopy is hinged at the front and has an internal frame for structural strength. The Martin-Baker US16E ejection seat is launched by a twin-catapult system housed on side rails.[159] There is a right-hand side stick and throttle hands-on throttle-and-stick system. For life support, an onboard oxygen-generation system (OBOGS) is fitted and powered by the Integrated Power Package (IPP), with an auxiliary oxygen bottle and backup oxygen system for emergencies.[160]

The F-35's helmet-mounted display system

The Vision Systems International[N 13] helmet display is a key piece of the F-35's human-machine interface. Instead of the head-up display mounted atop the dashboard of earlier fighters, the HMDS puts flight and combat information on the helmet visor, allowing the pilot to see it no matter which way they are facing.[161] Infrared and night vision imagery from the Distributed Aperture System can be displayed directly on the HMDS and enables the pilot to "see through" the aircraft. The HMDS allows an F-35 pilot to fire missiles at targets even when the nose of the aircraft is pointing elsewhere by cuing missile seekers at high angles off-boresight.[162][163] Each helmet costs $400,000.[164] The HMDS weighs more than traditional helmets, and there is concern that it can endanger lightweight pilots during ejection.[165]

Due to the HMDS's vibration, jitter, night-vision and sensor display problems during development, Lockheed Martin and Elbit issued a draft specification in 2011 for an alternative HMDS based on the AN/AVS-9 night vision goggles as backup, with BAE Systems chosen later that year.[166][167] A cockpit redesign would be needed to adopt an alternative HMDS.[168][169] Following progress on the baseline helmet, development on the alternative HMDS was halted in October 2013.[170][171] In 2016, the Gen 3 helmet with improved night vision camera, new liquid crystal displays, automated alignment and software enhancements was introduced with LRIP lot 7.[170]

Armament

[edit]
F-35A with all weapon bay doors open

To preserve its stealth shaping, the F-35 has two internal weapons bays each with two weapons stations. The two outboard weapon stations each can carry ordnance up to 2,500 lb (1,100 kg), or 1,500 lb (680 kg) for the F-35B, while the two inboard stations carry air-to-air missiles. Air-to-surface weapons for the outboard station include the Joint Direct Attack Munition (JDAM), Paveway series of bombs, Joint Standoff Weapon (JSOW), and cluster munitions (Wind Corrected Munitions Dispenser). The station can also carry multiple smaller munitions such as the GBU-39 Small Diameter Bombs (SDB), GBU-53/B StormBreaker and SPEAR 3; up to four SDBs can be carried per station for the F-35A and F-35C, and three for the F-35B.[172][173][174] The F-35A achieved certification to carry the B61 Mod 12 nuclear bomb in October 2023.[175] The inboard station can carry the AIM-120 AMRAAM and eventually the AIM-260 JATM. Two compartments behind the weapons bays contain flares, chaff, and towed decoys.[176]

An F-35A from the 4th Fighter Squadron, 388th Fighter Wing, Hill AFB, Utah, flies a strafing run at the Utah Test & Training Range in August 2018. This was the first operation use of the GAU-22/A of the F-35A aircraft.

The aircraft can use six external weapons stations for missions that do not require stealth.[177] The wingtip pylons each can carry an AIM-9X or AIM-132 ASRAAM and are canted outwards to reduce their radar cross-section.[178][179] Additionally, each wing has a 5,000 lb (2,300 kg) inboard station and a 2,500 lb (1,100 kg) middle station, or 1,500 lb (680 kg) for F-35B. The external wing stations can carry large air-to-surface weapons that would not fit inside the weapons bays such as the AGM-158 Joint Air to Surface Standoff Missile (JASSM) or AGM-158C LRASM cruise missile. An air-to-air missile load of eight AIM-120s and two AIM-9s is possible using internal and external weapons stations; a configuration of six 2,000 lb (910 kg) bombs, two AIM-120s and two AIM-9s can also be arranged.[162][180][181] The F-35 is armed with a 25 mm GAU-22/A rotary cannon, a lighter four-barrel variant of the GAU-12/U Equalizer.[182] On the F-35A this is mounted internally near the left wing root with 182 rounds carried;[citation needed] the gun is more effective against ground targets than the 20 mm gun carried by other USAF fighters.[dubiousdiscuss][citation needed] In 2020, a USAF report noted "unacceptable" accuracy problems with the GAU-22/A on the F-35A. These were due to "misalignments" in the gun's mount, which was also susceptible to cracking.[183] These problems were resolved by 2024.[184] The F-35B and F-35C have no internal gun and instead can use a Terma A/S multi-mission pod (MMP) carrying the GAU-22/A and 220 rounds; the pod is mounted on the centerline of the aircraft and shaped to reduce its radar cross-section.[182][185][verification needed] In lieu of the gun, the pod can also be used for different equipment and purposes, such as electronic warfare, aerial reconnaissance, or rear-facing tactical radar.[186][187] The pod was not susceptible to the accuracy issues that once plagued the gun on the F-35A variant,[183] though was apparently not problem-free.[184]

Lockheed Martin is developing a weapon rack called Sidekick that would enable the internal outboard station to carry two AIM-120s, thus increasing the internal air-to-air payload to six missiles, currently offered for Block 4.[188][189] Block 4 will also have a rearranged hydraulic line and bracket to allow the F-35B to carry four SDBs per internal outboard station; integration of the MBDA Meteor is also planned.[190][191] The USAF and USN are planning to integrate the AGM-88G AARGM-ER internally in the F-35A and F-35C.[192] Norway and Australia are funding an adaptation of the Naval Strike Missile (NSM) for the F-35; designated Joint Strike Missile (JSM), two missiles can be carried internally with an additional four externally.[193] Both hypersonic missiles and direct energy weapons such as solid-state laser are currently being considered as future upgrades; in 2024, Lockheed Martin disclosed its proposed Mako hypersonic missile, which can be carried internally in the F-35A and C and externally on the B.[194][N 14][198] Additionally, Lockheed Martin is studying integrating a fiber laser that uses spectral beam combining multiple individual laser modules into a single high-power beam, which can be scaled to various levels.[199]

F-35A weapon bays with two B61 nuclear bombs and 2 AIM-120 AMRAAM

The USAF plans for the F-35A to take up the close air support (CAS) mission in contested environments; amid criticism that it is not as well suited as a dedicated attack platform, USAF chief of staff Mark Welsh placed a focus on weapons for CAS sorties, including guided rockets, fragmentation rockets that shatter into individual projectiles before impact, and more compact ammunition for higher capacity gun pods.[200] Fragmentary rocket warheads create greater effects than cannon shells as each rocket creates a "thousand-round burst", delivering more projectiles than a strafing run.[201]

Engine

[edit]

The aircraft is powered by a single Pratt & Whitney F135 low-bypass augmented turbofan with rated thrust of 28,000 lbf (125 kN) at military power and 43,000 lbf (191 kN) with afterburner. Derived from the Pratt & Whitney F119 used by the F-22, the F135 has a larger fan and higher bypass ratio to increase subsonic thrust and fuel efficiency, and unlike the F119, is not optimized for supercruise.[202] The engine contributes to the F-35's stealth by having a low-observable augmenter, or afterburner, that incorporates fuel injectors into thick curved vanes; these vanes are covered by ceramic radar-absorbent materials and mask the turbine. The stealthy augmenter had problems with pressure pulsations, or "screech", at low altitude and high speed early in its development.[203] The low-observable axisymmetric nozzle consists of 15 partially overlapping flaps that create a sawtooth pattern at the trailing edge, which reduces radar signature and creates shed vortices that reduce the infrared signature of the exhaust plume.[204] Due to the engine's large dimensions, the U.S. Navy had to modify its underway replenishment system to facilitate at-sea logistics support.[205] The F-35's Integrated Power Package (IPP) performs power and thermal management and integrates environment control, auxiliary power unit, engine starting, and other functions into a single system.[206]

Illustration of the STOVL swivel nozzle, lift fan, and roll-control posts

The F135-PW-600 variant for the F-35B incorporates the Shaft-Driven Lift Fan (SDLF) to allow STOVL operations. Designed by Lockheed Martin and developed by Rolls-Royce, the SDLF, also known as the Rolls-Royce LiftSystem, consists of the lift fan, drive shaft, two roll posts, and a "three-bearing swivel module" (3BSM). The nozzle features three bearings resembling a short cylinder with nonparallel bases. As the toothed edges are rotated by motors, the nozzle swivels from being linear with the engine to being perpendicular. The thrust vectoring 3BSM nozzle allows the main engine exhaust to be deflected downward at the tail of the aircraft and is moved by a "fueldraulic" actuator that uses pressurized fuel as the working fluid.[207][208][209] Unlike the Harrier's Pegasus engine that entirely uses direct engine thrust for lift, the F-35B's system augments the swivel nozzle's thrust with the lift fan; the fan is powered by the low-pressure turbine through a drive shaft when engaged with a clutch and placed near the front of the aircraft to provide a torque countering that of the 3BSM nozzle.[210][211][212] Roll control during slow flight is achieved by diverting unheated engine bypass air through wing-mounted thrust nozzles called roll posts.[213][214]

An alternative engine, the General Electric/Allison/Rolls-Royce F136, was being developed in the 1990s and 2000s; originally, F-35 engines from Lot 6 onward were competitively tendered. Using technology from the General Electric YF120, the F136 was claimed to have a greater temperature margin than the F135 due to the higher mass flow design making full use of the inlet.[37][215] The F136 was canceled in December 2011 due to lack of funding.[216][217]

The F-35 is expected to receive propulsion upgrades over its lifecycle to adapt to emerging threats and enable additional capabilities. In 2016, the Adaptive Engine Transition Program (AETP) was launched to develop and test adaptive cycle engines, with one major potential application being the re-engining of the F-35; in 2018, both GE and P&W were awarded contracts to develop 45,000 lbf (200 kN) thrust class demonstrators, with the designations XA100 and XA101 respectively.[76] In addition to potential re-engining, P&W is also developing improvements to the baseline F135; the Engine Core Upgrade (ECU) is an update to the power module, originally called Growth Option 1.0 and then Engine Enhancement Package, that improves engine thrust and fuel burn by 5% and bleed air cooling capacity by 50% to support Block 4.[218][219][220] The F135 ECU was selected over AETP engines in 2023 to provide additional power and cooling for the F-35. Although GE had expected that the more revolutionary XA100 could enter service with the F-35A and C by 2027 and could be adapted for the F-35B, the increased cost and risk caused the USAF to choose the F135 ECU instead.[221][78]

Maintenance and logistics

[edit]

The F-35 is designed to require less maintenance than prior stealth aircraft. Some 95% of all field-replaceable parts are "one deep"—that is, nothing else needs to be removed to reach the desired part; for instance, the ejection seat can be replaced without removing the canopy. The F-35 has a fibermat radar-absorbent material (RAM) baked into the skin, which is more durable, easier to work with, and faster to cure than older RAM coatings; similar coatings are being considered for application on older stealth aircraft such as the F-22.[141][222][223] Skin corrosion on the F-22 led to the F-35 using a less galvanic corrosion-inducing skin gap filler, fewer gaps in the airframe skin needing filler, and better drainage.[224] The flight control system uses electro-hydrostatic actuators rather than traditional hydraulic systems; these controls can be powered by lithium-ion batteries in case of emergency.[225][226] Commonality between variants led to the USMC's first aircraft maintenance Field Training Detachment, which applied USAF lessons to their F-35 operations.[227]

The F-35 was initially supported by a computerized maintenance management system named Autonomic Logistics Information System (ALIS). In concept, any F-35 can be serviced at any maintenance facility and all parts can be globally tracked and shared as needed.[228] Due to numerous problems,[229] such as unreliable diagnoses, excessive connectivity requirements, and security vulnerabilities, ALIS is being replaced by the cloud-based Operational Data Integrated Network (ODIN).[230][231][232] From September 2020, ODIN base kits (OBKs)[233] were running ALIS software, as well as ODIN software, first at Marine Corps Air Station (MCAS) Yuma, Arizona, then at Naval Air Station Lemoore, California, in support of Strike Fighter Squadron (VFA) 125 on 16 July 2021, and then Nellis Air Force Base, Nevada, in support of the 422nd Test and Evaluation Squadron (TES) on 6 August 2021. In 2022, over a dozen more OBK sites will replace the ALIS's Standard Operating Unit unclassified (SOU-U) servers.[234] OBK performance is double that of ALIS.[235][234][233]

Operational history

[edit]

Testing

[edit]

The first F-35A, AA-1, conducted its engine run in September 2006 and first flew on 15 December 2006.[236] Unlike all subsequent aircraft, AA-1 did not have the weight optimization from SWAT; consequently, it mainly tested subsystems common to subsequent aircraft, such as the propulsion, electrical system, and cockpit displays. This aircraft was retired from flight testing in December 2009 and was used for live-fire testing at NAS China Lake.[237]

The first delivered USAF F-35A on its delivery flight to Eglin AFB, July 2011

The first F-35B, BF-1, flew on 11 June 2008, while the first weight-optimized F-35A and F-35C, AF-1 and CF-1, flew on 14 November 2009 and 6 June 2010 respectively. The F-35B's first hover was on 17 March 2010, followed by its first vertical landing the next day.[238] The F-35 Integrated Test Force (ITF) consisted of 18 aircraft at Edwards Air Force Base and Naval Air Station Patuxent River. Nine aircraft at Edwards, five F-35As, three F-35Bs, and one F-35C, performed flight sciences testing such as F-35A envelope expansion, flight loads, stores separation, as well as mission systems testing. The other nine aircraft at Patuxent River, five F-35Bs and four F-35Cs, were responsible for F-35B and C envelope expansion and STOVL and CV suitability testing. Additional carrier suitability testing was conducted at Naval Air Warfare Center Aircraft Division at Lakehurst, New Jersey. Two non-flying aircraft of each variant were used to test static loads and fatigue.[239] For testing avionics and mission systems, a modified Boeing 737-300 with a duplication of the cockpit, the Lockheed Martin CATBird has been used.[189] Field testing of the F-35's sensors were conducted during Exercise Northern Edge 2009 and 2011, serving as significant risk-reduction steps.[240][241]

Flight tests revealed several serious deficiencies that required costly redesigns, caused delays, and resulted in several fleet-wide groundings. In 2011, the F-35C failed to catch the arresting wire in all eight landing tests; a redesigned tail hook was delivered two years later.[242][243] By June 2009, many of the initial flight test targets had been accomplished but the program was behind schedule.[244] Software and mission systems were among the biggest sources of delays for the program, with sensor fusion proving especially challenging.[124] In fatigue testing, the F-35B suffered several premature cracks, requiring a redesign of the structure.[245] A third non-flying F-35B is currently planned to test the redesigned structure. The F-35B and C also had problems with the horizontal tails suffering heat damage from prolonged afterburner use.[N 15][248][249] Early flight control laws had problems with "wing drop"[N 16] and also made the airplane sluggish, with high angles-of-attack tests in 2015 against an F-16 showing a lack of energy.[250][251]

U.S. Marine Corps F-35B lands on JS Izumo

At-sea testing of the F-35B was first conducted aboard USS Wasp. In October 2011, two F-35Bs conducted three weeks of initial sea trials, called Development Test I.[252] The second F-35B sea trials, Development Test II, began in August 2013, with tests including nighttime operations; two aircraft completed 19 nighttime vertical landings using DAS imagery.[253][254] The first operational testing involving six F-35Bs was done on the Wasp in May 2015. The final Development Test III on USS America involving operations in high sea states was completed in late 2016.[255] A Royal Navy F-35 conducted the first "rolling" landing on board HMS Queen Elizabeth in October 2018.[256]

USN F-35C makes the aircraft's first arrested landing aboard the carrier USS Nimitz off the coast of San Diego

After the redesigned tail hook arrived, the F-35C's carrier-based Development Test I began in November 2014 aboard USS Nimitz and focused on basic day carrier operations and establishing launch and recovery handling procedures.[257] Development Test II, which focused on night operations, weapons loading, and full power launches, took place in October 2015. The final Development Test III was completed in August 2016, and included tests of asymmetric loads and certifying systems for landing qualifications and interoperability.[258] Operational test of the F-35C was conducted in 2018 and the first operational squadron achieved safe-for-flight milestone that December, paving the way for its introduction in 2019.[4][259]

The F-35's reliability and availability have fallen short of requirements, especially in the early years of testing. The ALIS maintenance and logistics system was plagued by excessive connectivity requirements and faulty diagnoses. In late 2017, the GAO reported the time needed to repair an F-35 part averaged 172 days, which was "twice the program's objective", and that shortage of spare parts was degrading readiness.[260] In 2019, while individual F-35 units have achieved mission-capable rates of over the target of 80% for short periods during deployed operations, fleet-wide rates remained below target. The fleet availability goal of 65% was also not met, although the trend shows improvement. Internal gun accuracy of the F-35A was unacceptable until misalignment issues were addressed by 2024.[248][261] As of 2020, the number of the program's most serious issues have been decreased by half.[262][184]

Operational test and evaluation (OT&E) with Block 3F, the final configuration for SDD, began in December 2018, but its completion was delayed particularly by technical problems in integration with the DOD's Joint Simulation Environment (JSE);[263] the F-35 finally completed all JSE trials in September 2023.[70]

United States

[edit]

Training

[edit]
The first F-35C Lightning II sortie takes off from VFA-101 at Eglin Air Force Base

The F-35A and F-35B were cleared for basic flight training in early 2012, although there were concerns over safety and performance due to lack of system maturity at the time.[264][265][266] During the Low Rate Initial Production (LRIP) phase, the three U.S. military services jointly developed tactics and procedures using flight simulators, testing effectiveness, discovering problems and refining design. On 10 September 2012, the USAF began an operational utility evaluation (OUE) of the F-35A, including logistical support, maintenance, personnel training, and pilot execution.[267][268]

A pair of F-35Cs and F/A-18E/Fs fly over NAS Fallon, home of TOPGUN, in September 2015.

The USMC F-35B Fleet Replacement Squadron (FRS) was initially based at Eglin AFB in 2012 alongside USAF F-35A training units, before moving to MCAS Beaufort in 2014 while another FRS was stood up at MCAS Miramar in 2020.[269][270] The USAF F-35A basic course is held at Eglin AFB and Luke AFB; in January 2013, training began at Eglin with capacity for 100 pilots and 2,100 maintainers at once.[271] Additionally, the 6th Weapons Squadron of the USAF Weapons School was activated at Nellis AFB in June 2017 for F-35A weapons instructor curriculum while the 65th Aggressor Squadron was reactivated with the F-35A in June 2022 to expand training against adversary stealth aircraft tactics.[272] The USN stood up its F-35C FRS in 2012 with VFA-101 at Eglin AFB, but operations would later be transferred and consolidated under VFA-125 at NAS Lemoore in 2019.[273] The F-35C was introduced to the Strike Fighter Tactics Instructor course, or TOPGUN, in 2020 and the additional capabilities of the aircraft greatly revamped the course syllabus.[274]

U.S. Marine Corps

[edit]

On 16 November 2012, the USMC received the first F-35B of VMFA-121 at MCAS Yuma.[275] The USMC declared Initial Operational Capability (IOC) for the F-35B in the Block 2B configuration on 31 July 2015 after operational trials, with some limitations in night operations, mission systems, and weapons carriage.[2][276] USMC F-35Bs participated in their first Red Flag exercise in July 2016 with 67 sorties conducted.[277] The first F-35B deployment occurred in 2017 at MCAS Iwakuni, Japan; combat employment began in July 2018 from the amphibious assault ship USS Essex, with the first combat strike on 27 September 2018 against a Taliban target in Afghanistan.[278]

In addition to deploying F-35Bs on amphibious assault ships, the USMC plans to disperse the aircraft among austere forward-deployed bases with shelter and concealment to enhance survivability while remaining close to a battlespace. Known as distributed STOVL operations (DSO), F-35Bs would operate from temporary bases in allied territory within hostile missile engagement zones and displace inside the enemy's 24- to 48-hour targeting cycle; this strategy allows F-35Bs to rapidly respond to operational needs, with mobile forward arming and refueling points (M-FARPs) accommodating KC-130 and MV-22 Osprey aircraft to rearm and refuel the jets, as well as littoral areas for sea links of mobile distribution sites. For higher echelons of maintenance, F-35Bs would return from M-FARPs to rear-area friendly bases or ships. Helicopter-portable metal planking is needed to protect unprepared roads from the F-35B's exhaust; the USMC are studying lighter heat-resistant options.[279] These operations have become part of the larger USMC Expeditionary Advanced Base Operations (EABO) concept.[280]

The first USMC F-35C squadron, VMFA-314, achieved Full Operational Capability in July 2021 and was first deployed on board USS Abraham Lincoln as a part of Carrier Air Wing 9 in January 2022.[281]

In 2024, Lt. Gen. Sami Sadat of Afghanistan described an operation using F-35Bs from USS Essex which bombed a Taliban position through cloud cover. "The impact [the F-35] left on my soldiers was amazing. Like, whoa, you know, we have this technology", Sadat said. "But also the impact on the Taliban was quite crippling, because they have never seen Afghan forces move in the winter, and they have never seen planes that could bomb through the clouds."[282]

On 9 November 2024, Marine F-35Cs carried out strikes on the Houthi movement in Yemen in the context of the Red Sea crisis, making it the first time the F-35C has been used in combat.[283]

U.S. Air Force

[edit]

USAF F-35A in the Block 3i configuration achieved IOC with the USAF's 34th Fighter Squadron at Hill Air Force Base, Utah on 2 August 2016.[3] F-35As conducted their first Red Flag exercise in 2017; system maturity had improved and the aircraft scored a kill ratio of 15:1 against an F-16 aggressor squadron in a high-threat environment.[284] The first USAF F-35A deployment occurred on 15 April 2019 to Al Dhafra Air Base, UAE.[285] On 27 April 2019, USAF F-35As were first used in combat in an airstrike on an Islamic State tunnel network in northern Iraq.[286]

For European basing, RAF Lakenheath in the UK was chosen as the first installation to station two F-35A squadrons, with 48 aircraft adding to the 48th Fighter Wing's existing F-15C and F-15E squadrons. The first aircraft of the 495th Fighter Squadron arrived on 15 December 2021.[287][288]

The F-35's operating cost is higher than some older USAF tactical aircraft. In fiscal year 2018, the F-35A's cost per flight hour (CPFH) was $44,000, a number that was reduced to $35,000 in 2019.[289] For comparison, in 2015 the CPFH of the A-10 was $17,716; the F-15C, $41,921; and the F-16C, $22,514.[290] Lockheed Martin hopes to reduce it to $25,000 by 2025 through performance-based logistics and other measures.[291]

According to US officials, F-35As and F-22s launched from land bases in the region, were used to attempt to draw surface-to-air missile fire ahead of B-2 bombing runs during the United States strikes on Iranian nuclear sites on 22 June 2025.[292][293][294]

U.S. Navy

[edit]
VFA-147 F-35C catches the wire on USS George Washington

The USN achieved operational status with the F-35C in Block 3F on 28 February 2019.[4] On 2 August 2021, the F-35C of VFA-147, as well as the CMV-22 Osprey, embarked on their maiden deployments as part of Carrier Air Wing 2 on board USS Carl Vinson.[295]

USN F-35Cs operating from the USS Carl Vinson took part the training exercise Pacific Stellar 2025 in February, along with the French and Japanese navies.[296]

In April 2025, F-35C's from VFA-97 shot down multiple Houthi drones in the Red Sea, making it the first time the Navy has used the jet in combat.[297]

United Kingdom

[edit]
F-35B ZM148 of No. 617 Squadron landing on HMS Queen Elizabeth, 2019

The United Kingdom's Royal Air Force and Royal Navy operate the F-35B. Called Lightning in British service,[298] it has replaced the Harrier GR9, retired in 2010, and Tornado GR4, retired in 2019. The F-35 is to be Britain's primary strike aircraft for the next three decades. One of the Royal Navy's requirements was a Shipborne Rolling and Vertical Landing (SRVL) mode to increase maximum landing weight by using wing lift during landing.[299][300] Like the Italian Navy, British F-35Bs use ski-jumps to fly from their aircraft carriers, HMS Queen Elizabeth and HMS Prince of Wales. British F-35Bs are not intended to use the Brimstone 2 missile.[301] In July 2013, Chief of the Air Staff Air Chief Marshal Sir Stephen Dalton announced that No. 617 Squadron would be the RAF's first operational F-35 squadron.[302][303]

The first British F-35 squadron was No. 17 (Reserve) Test and Evaluation Squadron (TES), which stood up on 12 April 2013 as the aircraft's Operational Evaluation Unit.[304] By June 2013, the RAF had received three F-35s of the 48 on order, initially based at Eglin Air Force Base.[305] In June 2015, the F-35B undertook its first launch from a ski-jump at NAS Patuxent River.[306] On 5 July 2017, it was announced the second UK-based RAF squadron would be No. 207 Squadron,[307] which reformed on 1 August 2019 as the Lightning Operational Conversion Unit (OCU).[308] No. 617 Squadron reformed on 18 April 2018 during a ceremony in Washington, D.C., becoming the first RAF front-line squadron to operate the type;[309] receiving its first four F-35Bs on 6 June, flying from MCAS Beaufort to RAF Marham.[310] On 10 January 2019, No. 617 Squadron and its F-35s were declared combat-ready.[311]

April 2019 saw the first overseas deployment of a UK F-35 squadron when No. 617 Squadron went to RAF Akrotiri, Cyprus.[312] This reportedly led on 25 June 2019 to the first combat use of an RAF F-35B: an armed reconnaissance flight searching for Islamic State targets in Iraq and Syria.[313] In October 2019, F-35s of 617 Squadron and No. 17 TES were embarked on HMS Queen Elizabeth for the first time.[314] No. 617 Squadron departed RAF Marham on 22 January 2020 for their first Exercise Red Flag with the Lightning.[315] As of November 2022, 26 F-35Bs were based in the United Kingdom (with 617 and 207 Squadrons) and a further three were permanently based in the United States (with 17 Squadron) for testing and evaluation purposes.[316]

The UK's second operational squadron is the Fleet Air Arm's 809 Naval Air Squadron, which stood up in December 2023.[317][318][319]

In June 2025, as part of its second phase of procurement, the UK announced plans to procure 12 F-35As, capable of delivering both conventional and nuclear weapons, including the B61-12 thermonuclear gravity bomb. The aircraft will form part of NATO's dual capable aircraft programme. The F35-As will be based in RAF Marham, to be used in a training role on routine operation, as part of the OCU. 15 F-35Bs are also planned in this phase.[320][321][322]

In July 2025, United States B61 nuclear weapons were redeployed to the US-operated RAF Lakenheath for the first time since 2008. The base operates F-35As and F-15Es, both capable of delivering the B61.[323][324]

Australia

[edit]
Four F-35As assigned to No. 3 Squadron RAAF in 2023

Australia's first F-35, designated A35-001, was manufactured in 2014, with flight training provided through international Pilot Training Centre (PTC) at Luke Air Force Base in Arizona.[325] The first two F-35s were unveiled to the Australian public on 3 March 2017 at the Avalon Airshow.[326] By 2021, the Royal Australian Air Force had accepted 26 F-35As, with nine in the US and 17 operating at No 3 Squadron and No 2 Operational Conversion Unit at RAAF Base Williamtown.[325] With 41 trained RAAF pilots and 225 trained technicians for maintenance, the fleet was declared ready to deploy on operations.[327] It was originally expected that Australia would receive all 72 F-35s by 2023.[326] Its final nine aircraft, which were the TR-3 version, arrived in Australia in December 2024.[328]

Israel

[edit]

The Israeli Air Force (IAF) declared the F-35 operationally capable on 6 December 2017.[329] According to Kuwaiti newspaper Al Jarida, in July 2018, a test mission of at least three IAF F-35s flew to Iran's capital Tehran and back to Tel Aviv. While publicly unconfirmed, regional leaders acted on the report; Iran's supreme leader Ali Khamenei reportedly fired the air force chief and commander of Iran's Revolutionary Guard Corps over the mission.[330][331]

On 22 May 2018, IAF chief Amikam Norkin said that the service had employed their F-35Is in two attacks on two battle fronts. This was part of the May 2018 Israel-Iran clashes, where airstrikes were claimed to target Iranian positions surrounding Syria's capital of Damascus and the buffer UNDOF Zone of the occupied Golan Heights.[332] This marks the first combat operation of an F-35 by any country.[13][333] Norkin said it had been flown "all over the Middle East", and showed photos of an F-35I flying over Beirut in daylight.[334] In July 2019, Israel expanded its strikes against Iranian missile shipments; IAF F-35Is allegedly struck Iranian targets in Iraq twice.[335]

In November 2020, the IAF announced the delivery of a unique F-35I testbed aircraft among a delivery of four aircraft received in August, to be used to test and integrate Israeli-produced weapons and electronic systems on F-35s received later. This is the only example of a testbed F-35 delivered to a non-US air force.[336][337]

On 11 May 2021, eight IAF F-35Is took part in an attack on 150 targets in Hamas' rocket array, including 50–70 launch pits in the northern Gaza Strip, as part of Operation Guardian of the Walls.[338] On 6 March 2022, the IDF stated that on 15 March 2021, F-35Is shot down two Iranian drones carrying weapons to the Gaza Strip.[339] This was the first operational shoot down and interception carried out by the F-35. They were also used in the Gaza war.[340][341][342] On 2 November 2023, the IDF posted on social media that they used an F-35I to shoot down a Houthi cruise missile over the Red Sea that was fired from Yemen during the Gaza war.[343]

F-35Is were used in airstrikes against Lebanon, including aerial refuelling in the country's airspace, in August and September 2024, as part of the Israel–Hezbollah conflict (2023–present).[344][150] F-35Is were used in the 29 September 2024 Israeli attacks on Yemen.[345] F-35Is were also reportedly involved in the October 2024 Israeli strikes on Iran.[346] The F-35 was also used during the June 2025 Israeli strikes on Iran, equipped with low-observable conformal fuel tanks to extend their range and allow operations over Iranian soil without mid-air refueling.[347] Iranian state-run media claimed that Iran shot down several Israeli F-35 jets, though the IDF denied the claims.[348][349]

Britain supplies Israel with parts for the F-35 through the global spares pool. Patrick Wintour wrote in The Guardian that, following criticism of Israel's role in the Gaza war, the legality of continuing this supply was questioned. The government in 2025 argued in a court case testing whether the law was broken by supplying Israel with F-35 parts usable to attack Palestinians in Gaza that preserving the British role in the F-35 jet fighter programme overrode UK laws on arms export controls and any UK obligation to prevent genocide in Israel.[84]

Italy

[edit]

Italy's F-35As were declared to have reached initial operational capability (IOC) on 30 November 2018. At the time Italy had taken delivery of 10 F-35As and one F-35B, with 2 F-35As and the one F-35B being stationed in the U.S. for training, the remaining 8 F-35As were stationed in Amendola.[350] Italian Navy F-35Bs have been operating from the Italian aircraft carrier ITS Cavour, where they have also conducted drills in the Philippine Sea with the US in 2024.[351][352] Construction in 2023 showed that Ghedi Air Base is planning to host F-35As for Italian delivery of US B61 nuclear weapons under NATO nuclear sharing.[353]

Japan

[edit]
F-35A in afterburner at JASDF Misawa Air Base

Japan's F-35As were declared to have reached initial operational capability (IOC) on 29 March 2019. At the time Japan had taken delivery of 10 F-35As stationed in Misawa Air Base. Japan plans to eventually acquire a total of 147 F-35s, which will include 42 F-35Bs. It plans to use the latter variant to equip Japan's Izumo-class multi-purpose destroyers.[354][355] On August 7, 2025, the first three Japanese F-35B's landed at Nyutabaru Air Base. Four more are to arrive by March 2026.[356]

Norway

[edit]
First Norwegian F-35A Lightning II at Luke Air Force Base, Arizona

On 6 November 2019 Norway declared initial operational capability (IOC) for its fleet of 15 F-35As out of a planned 52 F-35As.[357] On 6 January 2022 Norway's F-35As replaced its older F-16A and B models for the NATO quick reaction alert mission in the high north.[358] In April 2025, the total number of F-35s delivered totaled 49 out of 52.[359][360]

On 22 September 2023, two F-35As from the Royal Norwegian Air Force landed on a motorway near Tervo, Finland, showing, for the first time, that F-35As can operate from paved roads. Unlike the F-35B they cannot land vertically. The fighters were also refueled with their engines running. Major General Rolf Folland, Commander of the RNAF, said: "Fighter jets are vulnerable on the ground, so by being able to use small airfields – and now motorways – (this) increases our survivability in war",[361]

Netherlands

[edit]

On 27 December 2021, the Netherlands declared initial operational capability (IOC) for its fleet of 24 F-35As it has received to date from its order for 46 F-35As.[362] In 2022, the Netherlands announced they will order an additional six F-35s, totaling 52 aircraft ordered.[363] As of September 2024, 40 out of the 52 ordered have been delivered, and the Netherlands seeks to order another six jets to help completely phase out their F-16 fleet.[359]

Variants

[edit]
F-35 configurations
F-35A
F-35 variants in flight

The F-35 was designed with three initial variants – the F-35A, a CTOL land-based version; the F-35B, a STOVL version capable of use either on land or on aircraft carriers; and the F-35C, a CATOBAR carrier-based version. Since then, there has been work on the design of nationally specific versions for Israel and Canada.

F-35A

[edit]
JASDF F-35A Lightning II prepares to receive fuel from a USAF KC-135 Stratotanker in February 2025.

The F-35A is the conventional take-off and landing (CTOL) variant intended for the USAF and other air forces. It is the smallest, lightest version and capable of 9 g, the highest of all variants.

Although the F-35A currently conducts aerial refueling via boom and receptacle method, the aircraft can be modified for probe-and-drogue refueling if needed by the customer.[364][365] A drag chute pod can be installed on the F-35A, with the Royal Norwegian Air Force being the first operator to adopt it.[366] The F-35A has a tailhook designed to stop the aircraft during emergency situations. Unlike the more robust unit of the carrier-based F-35C, the F-35A's tailhook is a single-use device.[367]

F-35B

[edit]
F-35B cutaway with lift fan
F-35B conducting a vertical landing (note the rotated nozzle and the lift fan vent duct)

The F-35B is the short take-off and vertical landing (STOVL) variant of the aircraft. Similar in size to the A variant, the B sacrifices about a third of the A variant's fuel volume to accommodate the shaft-driven lift fan (SDLF).[368][369] This variant is limited to 7 g. Unlike other variants, the F-35B has no landing hook. The "STOVL/HOOK" control instead engages conversion between normal and vertical flight.[370][371] The F-35B is capable of Mach 1.6 (1,960 km/h; 1,220 mph) and can perform vertical and/or short take-off and landing (V/STOL).[213]

F-35C

[edit]

The F-35C is the carrier-based variant of the aircraft, designed for catapult-assisted take-off and barrier-arrested recovery (CATOBAR) operations from aircraft carriers. Compared to the F-35A, the F-35C incorporates several modifications to meet the specific demands of carrier operations. These include larger wings with foldable wingtips to reduce the aircraft's footprint for storage, enlarged control surfaces for improved handling at low speeds, a more robust tailhook for repeated use with carrier arrestor cables, a twin-wheel nose gear, and reinforced landing gear to withstand the stresses of arrested landings.[243] The increased wing area also allows for lower landing speeds and improves both range and payload capacity. The F-35C is limited to a maximum load factor of 7.5 g.[372]

F-35I "Adir"

[edit]

The F-35I Adir (Hebrew: אדיר, meaning "Awesome",[373] or "Mighty One"[374]) is an F-35A with unique Israeli modifications. The US initially refused to allow such changes before permitting Israel to integrate its own electronic warfare systems, including sensors and countermeasures. The main computer has a plug-and-play function for add-on systems; proposals include an external jamming pod, and new Israeli air-to-air missiles and guided bombs in the internal weapon bays.[375][376] A senior IAF official said that the F-35's stealth may be partly overcome within 10 years despite a 30 to 40-year service life, thus Israel's insistence on using their own electronic warfare systems.[377] In 2010, Israel Aerospace Industries (IAI) considered a two-seat F-35 concept; an IAI executive noted that there was a "known demand for two seats not only from Israel but from other air forces."[378] In 2008, IAI planned to produce conformal fuel tanks, as well as stealthy external fuel tanks;[379][380] these were reportedly used during the June 2025 Israeli airstrikes against Iran.[347]

Israel had ordered a total of 75 F-35Is by 2023, with 36 already delivered as of November 2022.[381][382]

Proposed variants

[edit]

CF-35

[edit]

The Canadian CF-35 was a proposed variant that would differ from the F-35A through the addition of a drogue parachute and the potential inclusion of an F-35B/C-style refueling probe.[366][383] In 2012, it was revealed that the CF-35 would employ the same boom refueling system as the F-35A.[384] One alternative proposal would have been the adoption of the F-35C for its probe refueling and lower landing speed; however, the Parliamentary Budget Officer's report cited the F-35C's limited performance and payload as being too high a price to pay.[385] Following the 2015 Federal Election the Liberal Party, whose campaign had included a pledge to cancel the F-35 procurement,[386] formed a new government and commenced an open competition to replace the existing CF-18 Hornet.[387] The CF-35 variant was deemed too expensive to develop, and was never considered. The Canadian government decided to not pursue any other modifications in the Future Fighter Capability Project, and instead focused on the potential procurement of the existing F-35A variant.[388]

On 28 March 2022, the Canadian Government began negotiations with Lockheed Martin for 88 F-35As[389] to replace the aging fleet of CF-18 fighters starting in 2025.[390] The aircraft are reported to cost up to CA$19bn total with a life-cycle cost estimated at CA$77bn over the course of the F-35 program.[391][392] On 9 January 2023, Canada formally confirmed the purchase of 88 aircraft. The initial delivery to the Royal Canadian Air Force in 2026 will be 4 aircraft, followed by 6 aircraft each in 2027–2028, and the rest to be delivered by 2032.[393][394] The additional characteristics confirmed for the CF-35[inconsistent] included the drag chute pod for landings at short/icy arctic runways, as well as the 'sidekick' system, which allows the CF-35 to carry up to 6 x AIM-120D missiles internally (instead of the typical internal capacity of 4 x AIM-120 missiles on other variants).[395]

New export variant

[edit]

In December 2021, it was reported that Lockheed Martin was developing a new variant for an unspecified foreign customer. The Department of Defense released US$49 million in funding for this work.[396]

Operators

[edit]
  Operates F-35A, F-35B and F-35C variants (United States)
  Operates F-35A and F-35B variants (Italy, Japan)
  Operates F-35A variant only (Australia, Denmark, Netherlands, Norway, South Korea)
  Operates F-35B variant and awaiting F-35B delivery (United Kingdom)
  Operates F-35I variant only (Israel)
  Awaiting delivery (F-35A: Belgium, Canada, Czech Republic, Finland, Germany, Greece, Poland, Romania, Switzerland; F-35A & F-35B: Singapore)
One of the RAAF's first two F-35As in December 2014
A Japan Air Self-Defense Force F-35A in flight
An F-35A Lightning II of the Royal Norwegian Air Force conducts a test flight over Fort Worth in October 2015.
First four RAF F-35Bs on a delivery flight to RAF Marham, June 2018
USN F-35C performs a touch-and-go landing aboard USS Abraham Lincoln.
 Australia
 Belgium
 Denmark
 Israel
 Italy
 Japan
 Netherlands
 Norway
 Poland
  • Polish Air Force – 32 F-35A "Husarz" Block 4 jets with "Technology Refresh 3" software update and drogue parachutes ordered, with six delivered as of 2025.[428][429][430][431][432] There are plans to order an additional 32 F-35s, which will comprise two squadrons.[433] The first domestic flights of the F-35 by Polish pilots took place in February 2025, signaling the start of the country's use of the aircraft.[432]
 South Korea
 United Kingdom
  • Royal Air Force and Royal Navy (owned by the RAF but jointly operated) – 41 F-35Bs received[442] with 37 in the UK after the loss of one aircraft in November 2021;[316][443][444][445] the other three are in the US where they are used for testing and training.[446] A total of 48 ordered as of 2021, with a total of 138 planned to be procured during the lifetime of the programme.[447] Whilst the UK was originally expected to only order the F-35B, in June 2025 the UK announced plans to procure 12 F-35As, enabling the UK to join NATO's nuclear mission due to the A variant's ability to carry B61 nuclear bombs internally, alongside 15 F-35Bs.[320][322] The first order of 48 aircraft is expected to be completed by 2026 with a secondary order of 27 aircraft (12 F-35A and 13 F-35B) to be procured by 2033.[448][449]
 United States

Future operators

[edit]
 Canada
  • Royal Canadian Air Force – 88 F-35As (Block 4) ordered on 9 January 2023. The first four are to be delivered in 2026, six in 2027, another six in 2028, and the remainder delivered by 2032.[454] The aircraft are to replace CF-18s delivered in the 1980s.[455][456]
Czech Republic
  • Czech Air Force – On 29 June 2023, the U.S. State Department announced the approval of a possible sale to the Czech Republic of F-35 aircraft, munitions and related equipment worth up to $5.62 billion.[457] On 29 January 2024, the Czech government signed a memorandum of understanding with the U.S. to buy 24 F-35As.[458] In September 2024, the Czech Republic signed a contract for F-35A logistics support.[459]
 Finland
 Germany
Greece
  • Hellenic Air Force – In 2024, Greece ordered 20 F-35As for delivery in late 2027 to early 2028,[467][468] with an option to buy 20 more.[469] The Greek F-35A production for 20 aircraft will "begin" with Lot 20, with full production starting in 2027, first delivery at the end of 2028, while the arrival of the first aircraft in Greece is expected for 2030, as per the VP for Strategy and Business Development and the VP for Customer Requirements of Lockheed Martin Aeronautics.[470][471]
 Romania
  • Romanian Air Force – Romania signed a contract for 32 F-35As worth $6.5 billion on 21 November 2024,[472] planning to buy 48 F-35A aircraft in two phases – a first phase of 32 and a second phase of 16. The first F-35s will arrive after 2030 and will replace the current Romanian F-16 fleet between 2034 and 2040.[473][474]
 Singapore
  • Republic of Singapore Air Force – 8 F-35As and 12 F-35Bs on order as of February 2024. The first 4 F-35Bs are to be delivered in 2026, while the other 8 are to be delivered in 2028. The 8 F-35As are expected to arrive by 2030.[475][476]
 Switzerland

Potential sales

[edit]

 India

 Chile
  • Chilean Air Force – Chile has entered formal negotiations with Lockheed Martin, expressing interest in the F-35A Lightning II variant as part of its air force modernization program. This initiative includes the planned retirement of the F-5 Tiger III fleet and at least 10 units of the F-16 MLU. The estimated acquisition period is between 2027 and 2030. Lockheed Martin has indicated its willingness to closely collaborate with Chilean authorities should the country decide to proceed with the integration of the F-35A into its combat aircraft fleet.[483]
 Morocco
  • Royal Moroccan Air Force – Morocco has entered into negotiations with the United States for the acquisition of the F-35 Lightning II stealth multirole fighter for its air force. These discussions have been ongoing for several months, with documents indicating that Israel has granted its approval in principle for the sale. This authorization is provided within the framework of the Qualitative Military Edge (QME), a clause of the Arms Export Control Act requiring that no arms sale in the region compromise Israel's military superiority. If finalized, the agreement would make Morocco the first African and Arab nation to operate the F-35.[484]

Cancellations

[edit]
 Republic of China
  • Republic of China Air Force – Taiwan has repeatedly expressed interest in buying the F-35 to deter and fight off any Chinese attempt to seize the island by force. It is reportedly most interested in the F-35B STOVL variant, which could enable the Republic of China Air Force to continue operations if China bombed the island's runways.[485] But the U.S. has repeatedly rebuffed this interest[486] – for example, in March 2009, September 2011,[487] early 2017[488] and March 2018. The usual reason given is to prevent provoking Beijing. But in April 2018, another reason for U.S. reluctance surfaced: concern that Chinese spies within the Taiwanese Armed Forces might gain classified data about the aircraft. In November 2018, it was reported that Taiwanese military leaders had abandoned efforts to buy the F-35 and would instead buy a larger number of F-16V Viper aircraft. The decision was reportedly motivated by concerns about industry independence, cost and espionage.[489]
Spain
  • Spanish Air and Space Force – The Spanish government explored the acquisition of the F-35 through requests for information and preliminary analysis,[490] but in August 2025 the option was formally ruled out.[491]
 Thailand
 Turkey
  • Turkish Air Force – 30 were ordered,[496] of up to 100 total planned.[497][498] Future purchases have been banned by the U.S. with contracts canceled by early 2020, following Turkey's decision to buy the S-400 missile system from Russia.[499] Six of Turkey's 30 ordered F-35As were completed as of 2019 (they are still kept in a hangar in the United States as of 2023[500][501] and so far haven't been transferred to the USAF, despite a modification in the 2020 Fiscal Year defense budget by the U.S. Congress which gives authority to do so if necessary),[502][503] and two more were at the assembly line in 2020.[502][503] The first four F-35As were delivered to Luke Air Force Base in 2018[504] and 2019[505] for the training of Turkish pilots.[506][507] On 20 July 2020, the U.S. government had formally approved the seizure of eight F-35As originally bound for Turkey and their transfer to the USAF, together with a contract to modify them to USAF specifications.[508] The U.S. has not refunded the $1.4 billion payment made by Turkey for purchasing the F-35A fighters as of January 2023.[500][501] On 1 February 2024, the United States expressed willingness to readmit Turkey into the F-35 program if Turkey agrees to give up its S-400 system.[509] After Trump and Erdoğan's phone call in March 2025, news was reported in the press that Trump could approve the sale of F-35s to Turkey if Turkey resolves the S-400 issue.[510] Following a meeting between U.S. President Trump and Turkish President Erdoğan at the White House on September 25, 2025, it was revealed that one of the proposed solutions, reported by the media in October 2025, stipulates the relocation of Turkey's S-400 missile systems to the Nakhchivan Autonomous Republic, an exclave of Azerbaijan which has a five-mile border with Turkey, as a precondition for lifting the CAATSA sanctions and approving the sale and transfer of F-35s and Patriot surface-to-air missile systems to Turkey.[511]
 United Arab Emirates
  • United Arab Emirates Air Force – Up to 50 F-35As planned.[512] On 27 January 2021, the Biden administration temporarily suspended the F-35 sales to the UAE.[513] After pausing the bill to review the sale, the Biden administration confirmed to move forward with the deal on 13 April 2021.[514] In December 2021, the UAE withdrew from purchasing F-35s as they did not agree to the additional terms of the transaction from the US.[515][516] On 14 September 2024, a senior UAE official said that the United Arab Emirates does not expect to resume talks with the U.S. about the F-35.[517]

Accidents and notable incidents

[edit]

The F-35 has been described as a relatively safe military aircraft.[518] Still, since 2014, more than a dozen have crashed or otherwise been involved in incidents that have killed or severely injured people or destroyed the aircraft. Some were caused by operator error; others by mechanical problems, some of which set the entire program back.[519]

Specifications (F-35A)

[edit]
F-35A three-view drawing

Data from Lockheed Martin: F-35 specifications,[520][521][522][523] Lockheed Martin: F-35 weaponry,[524] Lockheed Martin: F-35 Program Status,[112] F-35 Program brief,[162] FY2019 Select Acquisition Report (SAR),[372] Director of Operational Test & Evaluation[525]

General characteristics

  • Crew: 1
  • Length: 51.4 ft (15.7 m)
  • Wingspan: 35 ft (11 m)
  • Height: 14.4 ft (4.4 m)
  • Wing area: 460 sq ft (43 m2)
  • Aspect ratio: 2.66
  • Empty weight: 29,300 lb (13,290 kg)
  • Gross weight: 49,540 lb (22,471 kg)
  • Max takeoff weight: 65,918 lb (29,900 kg) [526]
  • Fuel capacity: 18,250 lb (8,278 kg) internal
  • Powerplant: 1 × Pratt & Whitney F135-PW-100 afterburning turbofan, 28,000 lbf (120 kN) thrust dry, 43,000 lbf (190 kN) with afterburner

Performance

  • Maximum speed: Mach 1.6 at high altitude
    • Mach 1.06, 700 knots (806 mph; 1,296 km/h) at sea level
  • Range: 1,500 nmi (1,700 mi, 2,800 km)
  • Combat range: 669 nmi (770 mi, 1,239 km) interdiction mission (air-to-surface) on internal fuel
    • 760 nmi (870 mi; 1,410 km), air-to-air configuration on internal fuel[527]
  • Service ceiling: 50,000 ft (15,000 m)
  • g limits: +9.0
  • Wing loading: 107.7 lb/sq ft (526 kg/m2) at gross weight
  • Thrust/weight: 0.87 at gross weight (1.07 at loaded weight with 50% internal fuel)

Armament

Avionics

Differences between variants

[edit]
F-35A
CTOL
F-35B
STOVL
F-35C
CV CATOBAR
Length 51.4 ft (15.7 m) 51.2 ft (15.6 m) 51.5 ft (15.7 m)
Wingspan 35 ft (10.7 m) 35 ft (10.7 m) 43 ft (13.1 m)
Height 14.4 ft (4.39 m) 14.3 ft (4.36 m) 14.7 ft (4.48 m)
Wing Area 460 sq ft (42.74 m2) 460 sq ft (42.74 m2) 668 sq ft (62.06 m2)
Empty weight 28,999 lb (13,154 kg) 32,472 lb (14,729 kg) 34,581 lb (15,686 kg)
Internal fuel 18,250 lb (8,278 kg) 13,500 lb (6,123 kg) 19,750 lb (8,958 kg)
Weapons payload 18,000 lb (8,160 kg) 15,000 lb (6,800 kg) 18,000 lb (8,160 kg)
Max takeoff weight 70,000 lb (31,800 kg) class 60,000 lb (27,200 kg) class 70,000 lb (31,800 kg) class
Range >1,200 nmi (2,200 km) >900 nmi (1,700 km) >1,200 nmi (2,200 km)
Combat radius on
internal fuel
669 nmi (1,239 km) 505 nmi (935 km) 670 nmi (1,241 km)
Thrust/weight
 • full fuel:
 • 50% fuel:

0.87
1.07

0.90
1.04

0.75
0.91
g limit +9.0 +7.0 +7.5

Appearances in media

[edit]

See also

[edit]

Related development

Aircraft of comparable role, configuration, and era

Related lists

Notes

[edit]

References

[edit]

Further reading

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia

The Lockheed Martin F-35 Lightning II is a family of single-engine, fifth-generation stealth developed primarily for the and allied nations under the . It features three main variants: the F-35A conventional takeoff and landing model for the U.S. Air Force, the F-35B short takeoff/vertical-landing variant for the U.S. Marine Corps and allies requiring STOVL capabilities, and the F-35C carrier-based version for the U.S. Navy. All variants share advanced , , and low-observable stealth design to enable network-centric operations, internal weapons carriage, and supersonic dash speeds exceeding Mach 1.6.
Initiated in the to replace aging fighters like the F-16, A-10, AV-8B Harrier, and F/A-18, the program has produced over 1,000 aircraft as of 2024, achieving a record 191 deliveries in 2025 across variants, accumulating more than 1 million flight hours including combat operations by all models. The F-35 emphasizes fifth-generation attributes such as radar-evading stealth through shape, materials, and coatings, integrated electro-optical targeting systems, and the for superior . However, the program has faced significant scrutiny for cost overruns, with total lifecycle expenses projected to exceed $2 trillion, including $1.58 trillion in sustainment alone, driven by complex maintenance and supply chain challenges. Despite these issues, the F-35 has achieved initial operational capability across U.S. services, with the F-35B declared operational by the Marine Corps in July 2015 and the F-35A by the Air Force in August 2016, and entered full-rate production for the F-35A in 2024, with flyaway costs stabilizing at approximately $82.5 million for F-35A, $109 million for F-35B, and $102.1 million for F-35C in recent lots. It operates with over a dozen international partners, including the , , , , and , forming the largest fleet of stealth fighters globally, with the U.S. accounting for more than two-thirds of units. Persistent controversies include reliability shortfalls—such as failure to meet mission-capable rate targets and engine performance metrics—and ongoing quality defects in production, alongside delays in software upgrades like Block 4 modernization. These factors, documented in Government Accountability Office and Department of Defense reports, highlight trade-offs between technological ambition and operational maturity in a program criticized for prioritizing capabilities over affordability and dependability.

Program History

Origins and Joint Strike Fighter Competition

The origins of the F-35 Lightning II trace back to the early , amid post-Cold War defense reviews and lessons from the 1991 , which highlighted the need for advanced multirole strike capabilities to replace aging fleets including the A-10 Thunderbolt II, F-16 Fighting Falcon, AV-8B Harrier II, and F/A-18 Hornet. In 1993, the U.S. Department of Defense initiated the Joint Advanced Strike Technology (JAST) program to explore affordable technologies for next-generation strike aircraft, merging it with the U.S. Marine Corps' (CALF) effort and incorporating short take-off and vertical landing (STOVL) requirements from the U.S.-U.K. Advanced Short Take-Off/Vertical Landing (ASTOVL) project established in 1986. Between 1994 and 1995, JAST identified core technologies such as stealth, , and reduced observability to support a family of variants for conventional takeoff and landing (), carrier-based (CV), and STOVL operations. By 1996, the program transitioned into the Joint Strike Fighter (JSF) competition, with initial concept development contracts awarded to four industry teams before downselecting to and for the Concept Demonstration Phase (CDP). This phase involved building and flying demonstrator aircraft: 's X-32, featuring a delta-wing design with direct-lift STOVL using a swiveling engine nozzle, and 's X-35, which employed a separate lift-fan system for STOVL alongside shaft-driven variants. The X-32A CTOL prototype achieved its first flight on September 18, 2000, while the X-35A followed later that year, with STOVL demonstrators testing vertical operations by early 2001 to validate performance against JSF requirements for commonality across variants, reduced lifecycle costs, and among U.S. services and allies like the . On October 26, 2001, Under Secretary of Defense for Acquisition, Technology, and Logistics Pierre "Pete" Aldridge announced Lockheed Martin's X-35 as the winner of the JSF competition, awarding the $19 billion System Development and Demonstration (SDD) contract over Boeing's X-32 primarily due to the X-35's superior STOVL solution, which better met Marine Corps expeditionary needs without compromising or carrier variants, alongside advantages in stealth integration and projected manufacturing efficiency. The selection emphasized a single-engine, supersonic design leveraging F-22 Raptor technologies for affordability, aiming for 80% parts commonality across the F-35A ( ), F-35B (Marine Corps STOVL), and F-35C ( carrier) variants to serve as a "fifth-generation" force multiplier for joint operations. This decision launched full-scale development, with international partners committing early funding shares to influence requirements and secure export slots.

Engineering and Production Milestones

The F-35 program's engineering development advanced through the System Development and Demonstration (SDD) phase after was awarded the primary contract on October 26, 2001, initiating detailed design, prototyping, and for the three variants. This phase incorporated technologies from prior programs, including stealth shaping and derived from the F-22 Raptor and F-117 , with extensive testing validating aerodynamic performance across subsonic to supersonic regimes. The X-35 demonstrator aircraft, precursors to production models, completed flight tests in 2000–2001, demonstrating short takeoff/vertical landing (STOVL) capabilities for the F-35B variant using a shaft-driven lift fan system. The first production-representative F-35A (AA-1) achieved its maiden flight on December 15, 2006, from Fort Worth, Texas, marking the start of over 17,000 cumulative flight test hours by 2018 to verify airframe integrity, propulsion integration with the Pratt & Whitney F135 engine, and avionics functionality. The F-35B followed with its initial flight on March 11, 2009 (after earlier STOVL tests), validating vertical landing operations, while the F-35C carrier variant flew first on November 7, 2011, confirming catapult launches and arrested recoveries with reinforced landing gear. Software Block 3F, enabling full combat capabilities including data fusion and weapons integration, completed operational testing in 2018, though concurrency between development and production introduced risks of retrofits. Production transitioned from SDD to low-rate initial production (LRIP) with Lot 1 authorization in 2007, yielding the first deliveries: an F-35A to the U.S. in March 2011 and an F-35B to the Marine Corps in June 2012. LRIP encompassed 14 lots through 2020, producing 857 aircraft at declining unit costs—from $133 million for F-35A in Lot 5 (2011) to $77.9 million in Lot 14 (2019)—driven by and maturation. This supply chain features major partner contributions to structural components: Northrop Grumman produces the center fuselage for all variants, BAE Systems manufactures the aft fuselage, while Lockheed Martin handles the forward fuselage and wings, followed by final assembly at the Fort Worth facility in Texas. Initial operational capability (IOC) followed: F-35B for the U.S. Marine Corps on July 31, 2015; F-35A for the on August 2, 2016; and F-35C for the on February 28, 2019. The program achieved Milestone C approval on March 12, 2024, authorizing full-rate production (FRP) after completing operational test and evaluation, including live-fire testing and cybersecurity validations, despite prior delays from reliability issues and software deficiencies. FRP lots, starting with Lot 15, target sustained annual output of 156 , though production ramped up to deliver a record 191 F-35s in 2025, surpassing the previous annual high of 142 jets; cumulative production exceeding 1,000 units by mid-2024 and flyaway costs stabilized at $80–90 million per F-35A. International production milestones include the first F-35 assembled outside the U.S. in (2014) and (2024), supporting partner nations' sustainment through shared logistics.

Technical Challenges and Software Upgrades

The F-35 program's adoption of concurrency—overlapping development, testing, and production phases—introduced significant technical challenges, requiring extensive retrofits on early to incorporate changes discovered post-production. This approach, intended to accelerate fielding, resulted in higher costs and delays as unresolved issues in software integration and hardware maturity necessitated modifications to hundreds of delivered jets. Software development proved particularly problematic, with the mission systems' complexity—encompassing over 8 million lines of code—leading to persistent instability and integration failures. Early blocks like Block 3F achieved initial operational capability but faced ongoing deficiencies in and reliability, compounded by late hardware arrivals that delayed lab and . In 2023, during TR-3 flight tests, pilots reported frequent in-flight system resets, highlighting immature software-hardware interfaces. The Autonomic Logistics Information System (ALIS), designed for and , encountered reliability issues including data inaccuracies, server crashes, and dependency on constant connectivity, which hampered fleet readiness and increased . These flaws prompted a shift to the Operational Data Integrated Network (), a cloud-based successor initiated in 2020, with initial hardware deployments completed by 2023 but full software fielding deferred to 2025 due to integration hurdles. Technology Refresh 3 (TR-3), a critical hardware and software upgrade featuring enhanced processors, expanded memory, and open mission , faced severe delays from 2023-2024 hardware maturation shortfalls and software validation problems, halting deliveries due to these issues. These were largely resolved by mid-2025, enabling a record 191 deliveries in 2025 and clearing the backlog. This $1.9 billion package enables Block 4 capabilities such as advanced sensors, electronic warfare enhancements, and weapons integration. However, as of early 2026, separate delays in integrating the new AN/APG-85 radar—due to configuration differences and mounting incompatibilities with the current setup—have led to some F-35s being delivered with the legacy AN/APG-81 radar instead. This compromises full capability but does not stop deliveries. Block 4 modernization, encompassing 75 new capabilities including engine upgrades and distributed aperture system improvements, is now projected for completion no earlier than 2031, exceeding original timelines by five years and budgets by over $6 billion due to TR-3 dependencies and ongoing concurrency effects. The Joint Program Office reorganized Block 4 and TR-3 into a subprogram in response, yet assessments indicate persistent risks from inadequate testing and contractor performance incentives that tolerate delays.

International Procurement and Cost Management

The F-35 program incorporates international participation to distribute development costs and leverage collective procurement for economies of scale. Seven U.S. allies serve as cost-sharing partners—the United Kingdom, Italy, the Netherlands, Australia, Canada, Denmark, and Norway—contributing to the system's research, development, and production phases in exchange for industrial workshare and access to technology. This structure, managed by the F-35 Joint Program Office (JPO), reduces redundant investments and spreads financial risk, with partners funding portions of the approximately $71.3 billion in research and development costs as of 2024. The United Kingdom, as the largest non-U.S. contributor, committed billions to the System Development and Demonstration phase, enabling its procurement of 138 F-35B variants for carrier operations. Partner nations have collectively committed to acquiring over 700 F-35 aircraft, including Australia's 144 F-35As, Italy's 90 (60 F-35As and 30 F-35Bs), the Netherlands' 52 F-35As, Norway's 52 F-35As, Denmark's 27 F-35As, and Canada's planned 88 F-35As. These procurements occur through cooperative agreements tied to development contributions, allowing partners priority in production lots and localized manufacturing, such as wing assembly in the UK or fuselages in Italy. Beyond partners, ten foreign military sales (FMS) customers, including Japan, Israel, and South Korea, have ordered hundreds more via the U.S. Defense Security Cooperation Agency, with Japan's program totaling an estimated $23.11 billion for additional aircraft as of December 2024. International orders, exceeding 1,000 aircraft to date across partners and FMS, amplify production volumes to lower unit costs, with flyaway prices for F-35As falling to approximately $62.2 million in recent lots due to mature supply chains and fixed-price incentives. Cost management emphasizes lifecycle affordability through shared sustainment infrastructure, including the global Autonomic Logistics Information System (ALIS) and its successor , which partners and FMS customers access for parts and . The JPO coordinates multinational efforts to cap operating and support costs, targeting reductions via competition for engine sustainment and software upgrades like Block 4, though actual annual sustainment expenses have risen to over $7 million per in some variants, exceeding early projections amid disruptions and . International participation mitigates U.S.-specific overruns by pooling demand—total program procurement now estimated at $325.8 billion for 2,456 U.S. plus foreign buys—but partners face independent challenges, such as Switzerland's $610 million for 36 F-35As in Lot 18 due to and labor pressures. assessments highlight persistent sustainment cost growth despite these mechanisms, attributing it to immature reliability and global supply dependencies, while program officials credit international scale for a 50% drop in Lockheed Martin's cost per flight hour since 2015.

Design and Technical Features

Airframe, Stealth, and Signatures Management

The F-35 employs a structure optimized for stealth, incorporating approximately one-third each of , aluminum, and composites by weight to balance strength, weight, and low-observability requirements. Composites constitute about 35% of the airframe, facilitating a trapezoidal mid-wing configuration, twin vertical tailfins, and an internal weapons bay that minimizes protrusions. components, including bulkheads and engine structures, provide durability in high-stress areas, while the overall integrates -absorbent materials and aligned edges to deflect waves. Stealth capabilities derive from all-aspect low-observability shaping, where the airframe's contours, including canted tailfins and smooth, curved surfaces, reduce radar reflections across multiple angles. The diverterless supersonic inlet (DSI) replaces traditional boundary layer diverters, eliminating radar-reflective gaps and mechanical parts while shielding engine fan faces from direct radar illumination, thereby lowering the radar cross-section (RCS) and reducing weight and maintenance needs. Internal carriage of weapons and fuel tanks further preserves a smooth external profile during stealth missions. Signatures management encompasses , , visual, and acoustic domains to achieve holistic low detectability. The F-35's RCS is estimated at 0.001 to 0.01 square meters in frontal aspects, comparable to a small or , though exact figures remain classified and vary by configuration and frequency band. IR signatures are mitigated through exhaust cooling, sinks, and ducting that disperses hot gases, reducing thermal detectability relative to non-stealth peers. Visual and acoustic signatures are lowered via dark, non-reflective coatings and noise suppression, while emissions are tightly controlled to avoid unintended detection. These features enable the F-35 to operate closer to threats before detection, prioritizing in contested environments over absolute .

Avionics, Sensors, and Data Fusion

The F-35 Lightning II's architecture centers on an integrated mission data system that processes inputs from multiple sensors to deliver fused to the pilot. This system includes a high-performance core processor and computing infrastructure capable of handling vast data streams in real time. The suite supports multirole operations by enabling simultaneous air-to-air and air-to-ground functions without compromising stealth or performance. Central to the sensor package is the active electronically scanned array (AESA) , developed by , operating in the X-band with approximately 1,676 transmit/receive modules. This provides long-range detection in active and passive modes for air-to-air and air-to-ground targets, while also functioning as an electronic warfare aperture for jamming and . It supports synthetic aperture mapping and ground moving target indication, enhancing precision strikes. The (EOTS), designated AAQ-40 and integrated beneath the forward , combines (FLIR) imaging, laser designation, and infrared search-and-track capabilities in a lightweight package weighing under 200 pounds. EOTS enables precision targeting for air-to-surface weapons and extended-range air-to-air threat detection without external pods, preserving the aircraft's low-observable profile. An advanced variant is under development for Block 4 upgrades, incorporating enhanced resolution and processing. Complementing these is the AN/AAQ-37 Distributed Aperture (DAS), comprising six sensors distributed around the airframe to provide 360-degree spherical coverage for missile warning, fire control, and imaging. DAS fuses imagery to generate a 360-degree panoramic view displayed on the helmet-mounted , allowing pilots to "see through" the aircraft structure and detect threats passively across mid-wave wavelengths. This also supports automatic threat cueing and navigation in degraded visual environments. Data fusion in the F-35 occurs via a dedicated engine that correlates tracks from , EOTS, DAS, and offboard sources into a unified representation, reducing pilot workload by prioritizing relevant threats and targets. This process leverages algorithmic integration to resolve ambiguities, such as distinguishing decoys from actual threats, and displays results on the panoramic display or . The (MADL) enables low-probability-of-intercept sharing of fused data among F-35 formations, extending while maintaining stealth. Initial operational capability for full fusion was achieved in software Block 3F, certified in 2015, though ongoing upgrades address fusion latency in dense threat environments.

Cockpit, Pilot Interface, and Ergonomics

The F-35 employs a architecture centered on the Panoramic Display (PCD), a contiguous 20-by-8-inch surface composed of two redundant 10-by-8-inch panels that integrate flight , sensor feeds, electronic warfare information, and moving maps via a hybrid interface. This setup supports configurable layouts for mission-specific needs, with upgrades to the PCD Electronics Unit enhancing and capacity for improved handling as of 2020. The primary pilot interface is the Gen III Helmet Mounted Display System (HMDS), developed by Collins Aerospace and Elbit Systems, which serves as the sole heads-up display equivalent, eliminating the traditional HUD used in prior fighters and marking the first such implementation in a tactical aircraft in over 50 years. The HMDS projects dual stereoscopic images onto the visor's waveguide optics—one per eye, focused at infinity—for overlaying critical flight parameters, tactical symbology, infrared video from the Electro-Optical Targeting System (EOTS), and distributed aperture system feeds, enabling virtual "see-through" visibility below the aircraft and 360-degree situational awareness by tracking head movements to cue sensors and weapons. Each helmet, costing approximately $400,000, undergoes custom anthropometric fitting to the pilot's head, neck, and eye measurements for optimal alignment and comfort during high-g maneuvers. Ergonomically, the cockpit prioritizes reduced pilot workload through and voice-activated controls, but stealth-driven design compromises limit physical rearward visibility from the canopy, with early test pilots in 2013 reporting vulnerability to tail chases absent compensatory systems like the HMDS. The US16E zero-zero optimizes terrain clearance, g-forces, and spinal injury risk via sequenced rocket deployment and harness tensioning, accommodating the HMDS during escape sequences following initial software and hardware refinements to address pre-2015 integration issues. Overall, these elements aim to fuse human factors with digital augmentation, though persistent HMDS challenges like display latency and weight distribution have prompted iterative Gen III enhancements for sustained operational efficacy.

Propulsion and Engine Performance

The Lockheed Martin F-35 Lightning II is powered by the afterburning turbofan engine across all variants, which derives its core technology from the F119 engine used in the F-22 Raptor. The F135 delivers over 40,000 pounds of thrust, enabling supersonic dash speeds up to Mach 1.6 while maintaining low-observable signatures through specialized coatings and design features. For the F-35A conventional takeoff and landing variant, the F135-PW-100 variant provides 43,000 pounds of thrust. The F-35C carrier variant employs the F135-PW-400, adapted with a low-infrared to mitigate heat detection during naval operations, while retaining comparable output to the PW-100. Both the F-35A and F-35C use a conventional cycle without vertical lift components, prioritizing stealth, thermal management, and integrated engine controls for sustained high-performance missions. In contrast, the F-35B short takeoff and vertical landing variant utilizes the F135-PW-600, integrated with the for STOVL capability. This system features a shaft-driven LiftFan, a 50-inch two-stage counter-rotating fan generating over 20,000 pounds of , powered by up to 29,000 shaft horsepower extracted from the main via a driveshaft and clutch assembly. Supplementary roll control is provided by wing-mounted doors directing bypass air, and the main nozzle incorporates 2D pitch vectoring for enhanced maneuverability during transition to vertical flight. This configuration allows the F-35B to achieve vertical lift without a dedicated auxiliary , optimizing for internal weapons and at the cost of slightly reduced range compared to variants. Ongoing enhancements include the F135 Engine Core Upgrade, a retrofittable modification supporting Block 4 avionics and weapons upgrades across all variants by improving durability and thermal capacity without altering base thrust ratings. Production contracts for later lots, such as 18 and 19, reflect continued investment in engine sustainment amid fleet expansion.

Armament Integration and Mission Flexibility

The F-35 integrates armaments via two internal weapons bays that preserve the aircraft's low-observable stealth profile by eliminating external drag and cross-section increases from protrusions. These bays, located under the , support carriage of precision-guided munitions and air-to-air missiles without compromising signatures in contested environments. External stations—wingtip rails and underwing/ pylons—enable expanded payloads exceeding 18,000 pounds in non-stealth missions where levels permit higher . Standard internal loadouts include two air-to-air missiles for beyond-visual-range engagements and two 2,000-pound GBU-31 JDAMs for precision strikes, alongside the F-35A's internal GAU-22/A 25mm with 181 rounds. The bays accommodate smaller bombs like the GBU-39/53 SDB series, allowing up to eight such munitions for saturation attacks while maintaining stealth. In 2024, the F-35A achieved certification for internal carriage of the B61-12 nuclear gravity bomb, marking the first stealth fighter capable of such integration for extended deterrence roles. Mission flexibility derives from rapid reconfiguration between roles, supported by modular interfaces and software-defined targeting that fuses data from onboard sensors to guide diverse munitions. The platform executes air superiority with internal AMRAAMs and AIM-9X short-range missiles, transitions to ground attack via laser- or GPS-guided bombs, and incorporates standoff weapons like JASSM-ER for suppression of enemy air defenses in later blocks. Variant-specific adaptations, such as the F-35B's reduced bay volume due to the lift fan, prioritize STOVL operations but retain multi-role versatility, with external loads trading stealth for heavier ordnance in permissive . This armament architecture enables the F-35 to adapt dynamically across air-to-air, , , and electronic attack missions, with total capacities reaching 22,000 pounds in fully loaded configurations. Integration efforts continue, incorporating hypersonic and long-range munitions to counter evolving threats without redesigning the .

Logistics, Maintainability, and Sustainment

The F-35 program's logistics framework relies on integrated information systems to manage supply chains, diagnostics, and maintenance scheduling across global operations. Initially, the Autonomic Logistics Information System (ALIS) was intended to provide real-time aircraft health data, predictive maintenance, and parts provisioning, but it encountered persistent issues including unreliable software, excessive false positives in diagnostics, cumbersome user interfaces, and dependency on constant internet connectivity that raised data sovereignty concerns for international partners. By 2021, the program transitioned to the successor Offline Data Integrated Network (ODIN), designed for offline functionality and improved reliability, with initial deployments completing core capabilities by early 2022, though full rollout faced delays due to software instability. Maintainability metrics for the F-35 highlight ongoing challenges in achieving design goals, particularly for stealth coatings and complex that demand specialized handling. Maintenance man-hours per flight hour (MMH/FH) for the F-35A variant improved to 4.79 by 2022 from higher initial rates, surpassing the program's nine MMH/FH mission requirement but falling short of broader sustainment targets aimed at legacy fighters like the F-16's approximately 10-12 MMH/FH. Reliability, measured by mean flight hours between critical failures, reached only 10.5 in 2023 after over 288,000 cumulative flight hours, well below the 100-hour goal, contributing to extended ground times for repairs. Depot-level delays, exacerbated by incomplete facilities and parts shortages, have further strained availability, with the Government Accountability Office (GAO) noting systemic underperformance in contractor-managed sustainment. Sustainment costs have escalated significantly, driven by low aircraft utilization and high dependency on proprietary contractor support. Lifetime sustainment estimates rose 44% to $1.58 trillion by 2023 from $1.1 trillion in 2018, even as projected flight hours declined 21% to mitigate expenses, with cost per flight hour stabilizing around 33,60033,600-42,000 for the F-35A, exceeding original $25,000 targets. Mission-capable rates, indicating aircraft ready for tasked missions, averaged 51.9% for F-35As in 2023, down from prior years and far below the 80% threshold, attributed primarily to spare parts shortages and backlogs rather than design flaws alone. The Joint Program Office contends recent per-aircraft and per-flight-hour costs have decreased by up to 34%, citing efficiencies in forward-deployed units, though assessments emphasize unresolved risks from contractor reliance and incomplete organic depot capabilities.

Operational History

Flight Testing and Capability Validation

The Joint Strike Fighter program's flight testing originated with the X-35 demonstrator aircraft, which conducted initial flights to validate competing concepts for conventional, carrier, and STOVL variants. The X-35A achieved its maiden flight on October 24, 2000, from Palmdale, California, demonstrating conventional takeoff and landing capabilities. Subsequent X-35B and X-35C flights in 2001 confirmed STOVL transitions and carrier approach maneuvers, paving the way for the Lockheed Martin design selection in 2001. The first production-representative F-35A, designated AA-1 or CF-1, rolled out on February 19, 2006, at , and completed its initial flight on December 15, 2006, from Naval Air Station Fort Worth, reaching 15,000 feet despite a minor sensor anomaly. Flight envelope expansion followed at , , under the 461st Squadron, encompassing structural loads, , and tests across subsonic to supersonic regimes. The F-35B variant's BF-1 achieved first flight in November 2008, validating short takeoff and vertical landing modes through Mode 1 and Mode 2 testing, while the F-35C's CF-1 flew initially in 2009, focusing on launches and arrested recoveries. Developmental testing accumulated over 10,000 flight hours by 2018, including 183 weapons separation tests, 46 weapons delivery accuracy evaluations, and 33 mission effectiveness assessments to confirm sensor fusion, stealth signatures, and multi-role integration. Challenges included F-35B STOVL system redesigns, which delayed the program by three years and added $6.5 billion in costs due to propulsion integration issues. Software deficiencies, such as those in Block 3F upgrades, extended validation timelines, with initial operational test and evaluation (IOT&E) commencing in December 2018 at Edwards by the 31st Test and Evaluation Squadron, evaluating full warfighting scenarios. Capability validation progressed through phases like Block 2B Mode 4 in 2014 and TR-3 software first flights in 2023, addressing electronic warfare and . Despite persistent issues like 857 identified deficiencies—only seven classified as critical—the program achieved milestones in supersonic operations and weapons environments, supporting full-rate production approval in March 2024 following IOT&E completion. Testing at Edwards and emphasized causal factors in performance, such as lift fan efficiency for F-35B hover and cross-section management under loads, ensuring empirical substantiation of design claims.

Combat Deployments and Real-World Performance

The F-35 achieved its first confirmed combat use on May 22, 2018, when F-35I Adir aircraft conducted airstrikes against Iranian military targets in , penetrating airspace defended by Russian-supplied S-300 systems without detection. Israeli officials reported that the stealth capabilities of the F-35I enabled undetected ingress and egress, marking the platform's debut in operational strikes amid heightened tensions with Iranian forces. Subsequent Israeli operations have included F-35I missions over as recently as October 26, 2024, targeting threats in areas like , demonstrating sustained employment in contested environments with integrated Israeli modifications for electronic warfare and precision munitions. U.S. forces initiated F-35 deployments with the Air Force's F-35A variant in 2019, stationing aircraft at in the for operations in the U.S. Central Command area, where they conducted initial real-world missions including intelligence, surveillance, and reconnaissance alongside limited strikes. The U.S. Marine Corps followed with F-35B deployments, exemplified by Marine Fighter Attack Squadron 542 (), which in 2025 completed a historic rotation logging 1,099 combat sorties and 4,736 mishap-free flight hours over five months, achieving one of the highest readiness rates in the fleet during forward operations from amphibious ships and expeditionary bases. These deployments highlighted the F-35's role as a force multiplier, fusing sensor data to share real-time awareness with legacy aircraft and ground units, though specific kinetic outcomes remain classified. In real-world performance, the F-35 has demonstrated high survivability and mission success rates in operational theaters, with no reported losses attributable to enemy action across Israeli and U.S. uses as of 2025; Israeli pilots have credited its low-observable signatures and advanced for enabling strikes on high-value targets amid dense air defenses. U.S. evaluations post-deployment emphasize its beyond-visual-range engagement superiority, where integrated provide pilots with superior , outperforming fourth-generation fighters in networked kill chains during Central Command patrols. exercises like Red Flag have validated these attributes, with F-35s achieving sortie generation rates exceeding 80% in high-threat simulations and maintaining undefeated records in beyond-visual-range scenarios since software Block 3F upgrades in 2017, though within-visual-range dogfighting remains a secondary capability optimized for evasion rather than dominance. Reliability metrics from deployments show variability, with forward units sustaining high operational tempos but overall fleet mission-capable rates averaging around 55-65% due to maintenance-intensive stealth coatings and software dependencies, impacting peacetime availability more than execution.

U.S. Military Service Introductions

The United States Marine Corps achieved initial operational capability (IOC) for the F-35B short takeoff/vertical landing variant on July 31, 2015, with Marine Fighter Attack Squadron 121 (VMFA-121) "Green Knights" at Marine Corps Air Station Miramar, California, certifying 10 aircraft as combat-ready for worldwide deployment. This milestone followed the squadron's completion of operational readiness evaluations, enabling the F-35B to integrate into Marine expeditionary units for austere airfield operations and shipboard STOVL missions. VMFA-121 became the first Fleet Marine Force squadron to operate the F-35B, transitioning from legacy AV-8B Harriers and emphasizing the variant's role in distributed maritime operations. The declared IOC for the F-35A conventional takeoff and landing variant on August 2, 2016, with the "Rude Rams" of the at , , achieving combat readiness with 12 Block 3i-configured aircraft. This followed the delivery of the first production F-35A to the on May 5, 2011, at Lockheed Martin's Fort Worth facility, with initial operational training commencing at . The 's certification marked the transition to fifth-generation capabilities for conventional , focusing on air superiority, ground attack, and intelligence, surveillance, and reconnaissance missions from fixed bases. The United States Navy attained IOC for the F-35C carrier variant on February 28, 2019, with Strike Fighter Squadron 147 (VFA-147) "Argonauts" at , , after completing carrier qualifications and certifying a squadron of 10 . Key precursors included the first F-35C delivery on June 22, 2013, to the 33rd Fighter Wing at for training, and the variant's inaugural arrested carrier landing on November 3, 2014, aboard (CVN-68). VFA-147's readiness emphasized carrier-based stealth strike and electronic warfare integration, supporting sea control and from aircraft carriers like .

Allied Operations and Joint Exercises

The Royal Australian Air Force (RAAF) has integrated its F-35A fleet into multinational exercises, including Talisman Sabre 2025, where U.S. Air Force pilots conducted the first international interfly by flying RAAF F-35As on July 16, 2025, in , , enhancing interoperability among allies. This exercise, held from July 13 to August 4, 2025, involved RAAF F-35As alongside U.S. and partner nation aircraft for combined training in amphibious and air operations. Similarly, RAAF F-35As participated in 2024 from July 12 to August 2, marking a key venue for allied air training in the . In NATO contexts, F-35s from allied nations have featured prominently in joint maneuvers, such as Steadfast Noon 2025, where F-35s led nuclear deterrence simulations across starting October 2025, involving multiple members to validate alliance capabilities. An earlier multinational basic fighter maneuvering exercise in in June 2024 united F-35s from various operators, including U.S. and European allies, to refine tactics in a contested environment. Nordic allies conducted initial inter-allied fifth-generation training in March 2024, with Danish F-35s engaging Swedish Gripens over Danish airspace on March 11 and 13. The Royal Air Force (RAF) has employed F-35B variants in carrier-based operations during joint exercises, such as flight trials aboard in the as part of Operation Achillean in November 2022, integrating with allied forces for strike group proficiency. British F-35Bs also supported multinational training during Exercise Med Strike, conducting deck operations from with U.S. partners. In the , RAF pilots flew RAAF F-35As during Talisman Sabre 2025, building on prior interoperability efforts like the 2023 Lightning-X initiative. Other allied operators have expanded F-35 roles in regional exercises; for instance, RAAF F-35As joined Exercise Guardian 2025 in starting September 30, 2025, at with eight aircraft from No. 3 Squadron training alongside units. In Exercise Bersama Lima 2025, held in from September 19 to October 6, RAAF F-35As conducted mid-flight maneuvers under the Five Power Defence Arrangements framework. These activities underscore the F-35's role in fostering coalition data sharing and tactical alignment among partner nations.

Variants

F-35A Conventional Takeoff and Landing

The F-35A Lightning II is the conventional takeoff and landing (CTOL) variant of the Joint Strike Fighter family, designed primarily for U.S. Air Force operations from standard runways at air bases. Selected as part of the JSF program approved on October 26, 2001, the F-35A emphasizes high-performance conventional flight without the structural compromises required for short takeoff/vertical landing or carrier compatibility found in the F-35B and F-35C variants. This allows for greater internal fuel capacity of 18,498 pounds and a maximum takeoff weight in the 70,000-pound class, enhancing range exceeding 1,350 miles on internal fuel alone. The first F-35A prototype, designated AA-1, achieved its maiden flight on December 15, 2006, from , validating core and propulsion integration. Powered by a single F135-PW-100 engine producing 43,000 pounds of thrust, the F-35A accelerates along using conventional high-lift devices and for short-field performance, though it requires a minimum length of approximately 8,000 feet for safe takeoff at maximum gross weight under standard conditions. Post-takeoff, it attains a top speed of Mach 1.6 (approximately 1,200 mph) and sustains 9G maneuvers, with a service ceiling above 50,000 feet. Landing operations rely on conventional wheel braking, spoilers, and reverse thrust unavailable in turbofans, supported by the aircraft's 51-foot length, 35-foot wingspan, and low approach speeds enabled by advanced controls and stealth-optimized . Unlike carrier variants, the F-35A lacks a tailhook as standard equipment, focusing instead on unprepared field compatibility within limits, though optimal performance demands paved surfaces to accommodate its 14-foot height and 18,000-pound capacity. Initial operational capability for the U.S. was declared in August 2016, following extensive that confirmed reliability across diverse mission profiles.

F-35B Short Takeoff/Vertical Landing

The F-35B is the short takeoff and vertical landing (STOVL) variant of the F-35 Lightning II, designed primarily for the to operate from amphibious assault ships, expeditionary airfields, and austere locations without requiring long runways. It achieves this through the integration of the , which includes a shaft-driven LiftFan positioned forward of the engine, a three-bearing swivel module for the main engine's , and roll posts for lateral control during hover. The LiftFan, powered by the engine via a clutch and shaft, generates upward thrust equivalent to approximately 20,000 pounds; the integrated LiftSystem provides a total vertical thrust of approximately 41,900–42,000 lbf, enabling balanced hovering and vertical takeoff/landing around the center of gravity, while preserving the aircraft's supersonic performance in conventional flight modes. This system marks the first production vertical lift technology for a supersonic fighter jet, allowing the F-35B to transition seamlessly between jet-borne hover and wing-borne flight. Development of the F-35B stemmed from the Joint Strike Fighter program's demonstrator phase, where the X-35B prototype validated STOVL feasibility with its first hover flight in 2001. The production F-35B achieved its maiden flight on June 11, 2008, initially in conventional takeoff and landing configuration, with STOVL mode testing commencing in early 2009. Key milestones included the first vertical takeoff and landing on March 18, 2010, and the initial shipboard vertical landing aboard the amphibious assault ship USS Wasp in October 2011. These tests confirmed the variant's ability to operate from decks as short as 600 feet for short takeoffs, though full vertical landings require precise control to manage hot gas reingestion risks during hover near surfaces. In terms of specifications, the F-35B features a of 35 feet, an empty of 32,300 pounds, and a maximum gross of around 60,000 pounds, with a top speed of Mach 1.6 powered by the F135-PW-600 engine delivering 125 kN of dry . Its STOVL capability supports Marine Air-Ground Task Force operations, enabling missions such as air superiority, , and intelligence, surveillance, and reconnaissance from forward-deployed positions inaccessible to conventional fighters. Operationally, U.S. Marine Corps squadrons have demonstrated reliability, with one deployed unit logging over 5,000 flight hours without mishaps by October 2025, underscoring the variant's maturation despite early engineering hurdles. The STOVL design imposes trade-offs, including a reduced internal capacity and compared to the F-35A—approximately 20% less range and weapons load—to accommodate the LiftSystem's weight and volume, which totals about 6,000 pounds. Early development faced setbacks, such as engine durability issues and vulnerabilities that delayed the program by three years and added $6.5 billion in costs, prompting scrutiny over whether STOVL requirements compromised overall JSF performance. Nonetheless, empirical testing verified key performance parameters, including hover efficiency and short takeoff distances under combat loads, validating the variant's utility for where carrier or fixed-base alternatives are unavailable.

F-35C Carrier-Based Variant

The F-35C Lightning II serves as the U.S. Navy's carrier-based variant within the Joint Strike Fighter program, engineered for catapult-assisted takeoff but arrested-recovery (CATOBAR) operations on Nimitz- and Ford-class aircraft carriers. It incorporates a wingspan of 43 feet with folding wingtips for efficient deck storage, reinforced landing gear capable of absorbing the high-impact forces of arrested landings at sink rates up to 24 feet per second, a tailhook for wire engagement, and internal fuel capacity of approximately 19,750 pounds to enable combat radius exceeding 600 nautical miles on internal fuel alone. These adaptations address the aerodynamic and structural demands of naval aviation, providing lower wing loading than the F-35A for enhanced low-speed stability during approach and recovery phases, while preserving fifth-generation stealth, sensor fusion, and Mach 1.6 top speed. Development traced back to the X-35C demonstrator, which conducted its first flight on December 16, 2000, validating carrier-compatible design elements like larger wings and simulations. The production F-35C achieved its on June 7, 2010, from Lockheed Martin's Fort Worth facility, logging a 57-minute to test basic handling. The accepted delivery of its first operational F-35C aircraft, designated CF-1, on June 24, 2013, assigning it to Strike Fighter Squadron 101 () at , , for pilot training and tactics development. Key milestones included initial carrier integration testing, with the variant demonstrating operational wing folding during shipboard trials aboard USS Abraham Lincoln in March 2018, where and pilots executed 140 day and night arrested landings to certify carrier suitability. The F-35C attained Initial Operational Capability (IOC) on February 28, 2019, after , the "Argonauts," completed required manning, training, and equipping to undertake assigned missions, including safe-for-flight certification following carrier qualifications on . The squadron embarked on its inaugural deployment in August 2021 aboard , integrating F-35C operations into routines and marking the first forward deployment of a stealth carrier-based in U.S. history.

F-35I Adir Israel-Specific Configuration

The F-35I Adir, designated as a customized subvariant of the F-35A for the , incorporates Israel-developed electronic warfare systems, including an indigenous suite from that replaces the standard configuration to enhance compatibility with national defense requirements. This setup integrates Israeli sensors, countermeasures, and command-and-control software via a modified main computer, enabling seamless operation with domestically produced munitions such as guided bombs and air-to-air missiles carried internally to preserve stealth. Key structural adaptations include provisions for extended range through conformal fuel tanks and optimized tailored for regional threats, allowing the to interface with Israel's layered air defense architecture without reliance on the U.S.-centric ALIS/ logistics . The configuration supports "beast mode" operations with external ordnance loads exceeding standard stealth limits, as demonstrated in , while maintaining core F-35A attributes like the engine and radar. Future enhancements encompass Technology Refresh 3 (TR-3) hardware for improved computing and Block 4 software upgrades for and weapon interoperability, implemented in collaboration with the Israeli Ministry of Defense. Procurement began with an initial order of 50 aircraft in 2010, expanded to 75 by a $3 billion deal signed on June 4, 2024, with deliveries reaching approximately 39 operational units by mid-2025 across three squadrons at . The first F-35I arrived on June 22, 2016, achieving initial operational capability in December 2017, independent of U.S. software dependencies that have plagued other operators. This self-reliant sustainment yields mission-capable rates above 90%, with 35 of 39 aircraft ready as of June 2025, contrasting with lower U.S. averages due to 's focused and indigenous modifications.

Proposed and Developmental Variants

The Block 4 upgrade program represents the most extensive developmental effort for the F-35 fleet, incorporating approximately 75 major enhancements across all variants to address evolving threats and improve mission effectiveness. These include hardware and software modifications such as the integration of the APG-85 radar, which offers greater range and resolution than the existing APG-81, and upgrades to the AN/AAQ-37 Electro-Optical Distributed Aperture System (EO-DAS) for enhanced capabilities. The program also features an advanced (EOTS) for improved precision targeting and weapon employment, with full operational capability targeted for the late 2020s following initial testing. Complementing Block 4, the Technology Refresh 3 (TR-3) configuration focuses on computational upgrades, including quad-core processors and increased memory to support advanced algorithms and , enabling the aircraft to handle greater data loads from networked operations. First demonstrated in in early 2020, TR-3 addresses prior limitations in processing power that delayed deliveries from mid-2023 to mid-2024, with retrofits planned for earlier production lots to restore full mission capabilities. Beyond these, Lockheed Martin has proposed conceptual evolutions of the F-35 platform, including a "5-plus generation" reworked configuration pitched as an interim "bridging fighter" to extend ahead of sixth-generation platforms like the (NGAD) program. This developmental pathway emphasizes modular upgrades for stealth, propulsion, and autonomy integration, potentially incorporating adaptive cycle engines for improved and performance, though no new variants have been formally contracted as of 2025. Such proposals aim to sustain the F-35's role in collaborative combat aircraft ecosystems, where manned F-35s direct unmanned loyal wingmen, but implementation remains contingent on U.S. Department of Defense funding priorities amid rising program costs.

Operators and Global Adoption

Primary Operators and Fleet Sizes

The United States military services constitute the primary operators of the F-35 Lightning II, accounting for the majority of global deliveries and operational aircraft. As of late August 2025, over 1,230 F-35s had been delivered worldwide, with the U.S. receiving the largest share across its , Marine Corps, and branches. The U.S. Air Force fields the F-35A conventional takeoff and landing variant, intended to replace aging F-16 and A-10 fleets in multirole strike and air superiority roles. The U.S. Marine Corps primarily operates the F-35B short takeoff/vertical landing model for expeditionary operations, supplemented by a smaller number of F-35C carrier variants, while the U.S. Navy employs the F-35C exclusively for carrier-based missions.
OperatorVariant(s)Planned Fleet Size
U.S. Air ForceF-35A1,763
U.S. Marine CorpsF-35B / F-35C280 / 140
U.S. NavyF-35C273
Among international operators, the maintains a significant fleet of F-35B aircraft jointly operated by the Royal Air Force and for carrier strike capabilities, with deliveries supporting initial operational capability achieved in 2020. operates the customized F-35I Adir variant, integrated with indigenous and weapons, achieving approximately 39 aircraft in service by mid-2025 out of a planned total of 75. Other notable primary operators include (planned 147 across A and B variants) and (100 F-35As), reflecting the program's emphasis on allied within U.S.-led coalitions. Lockheed Martin delivered a record 191 F-35s in 2025, surpassing the previous annual high of 142, primarily to U.S. and partner nations, amid ongoing production lots.

Export Successes and Partner Nations

The F-35 Lightning II has seen substantial export success through the Joint Strike Fighter (JSF) program and Foreign Military Sales (FMS), with 19 allied nations operating or ordering the aircraft as of 2025, representing over 900 delivered units internationally alongside more than 1,700 on order. Original JSF partners, including Level 1 collaborator the United Kingdom and Level 2 nations such as Australia, Italy, the Netherlands, Canada, Denmark, and Norway, committed early to co-development and procurement, fostering interoperability and shared sustainment costs. These partnerships have enabled technology sharing and industrial participation, with non-US partners acquiring over 800 aircraft collectively. Japan stands as the largest export customer, ordering 147 F-35s (105 F-35A and 42 F-35B) to bolster its air defense amid regional threats, with deliveries commencing in and ongoing production supporting local final assembly. Other significant deals include the United Kingdom's commitment to 138 F-35B variants for carrier operations, Australia's 100 F-35A for replacing legacy F/A-18s, and Israel's customized 75+ F-35I "Adir" jets featuring indigenous avionics and weapons integration. has ordered 60 F-35A, while newer adopters like (32 F-35A), (64 F-35A), and (34 F-35A) have integrated the platform into frameworks, enhancing collective deterrence. 2025 milestones for these nations included Finland's first F-35 rollout ceremony on December 16, Belgium's initial in-country aircraft arrivals in October, and Norway's completion of its 52 F-35A fleet deliveries.
NationOrdered AircraftPrimary VariantNotes
147F-35A/BLargest foreign buyer; local assembly for F-35A.
138F-35BJSF partner; STOVL for Queen Elizabeth-class carriers.
100F-35AFull operational capability achieved in 2023.
75+F-35IModified for Israeli systems; combat debut in 2018.
90F-35A/BJSF partner; assembly line in Cameri.
Export momentum continued into with recent contracts, including a $24 billion deal for 296 additional F-35s across multiple nations, underscoring sustained demand despite program challenges. completed delivery of its 52 F-35A fleet in 2025, becoming one of the first to achieve full operational capability among European operators. This global adoption reflects the jet's role in allied force modernization, though sustainment costs and software upgrades remain points of international coordination.

Potential Acquisitions and Program Expansions

is considering the acquisition of 15 additional F-35A aircraft to expand its existing fleet of 35 ordered in , with evaluations ongoing as of October 2025 to enhance nuclear-sharing capabilities within . approved a $4.5 billion for more F-35s in October 2025, building on its initial order of 27 aircraft and incorporating Collaborative Combat Aircraft wingman drones for enhanced operational integration. has pursued F-35 acquisitions, with announcements in 2025 prompting regional security concerns among North African neighbors due to the stealth fighter's advanced capabilities. Greece and Singapore are projected to integrate F-35 variants into their air forces by 2030, following letters of intent and negotiations aimed at modernizing their fleets against evolving threats in the Mediterranean and , respectively. Poland maintains plans to increase its F-35 holdings beyond the initial 32 aircraft, prioritizing additional fighters in short-term procurements while deferring detailed planning documents. Program expansions include Lockheed Martin's September 2025 contract for nearly 300 F-35s across Lots 18 and 19, supporting U.S. and partner sustainment with deliveries commencing in 2026. The Block 4 upgrade, incorporating over 80 enhancements such as the APG-85 and improved thermal management, faces delays to full operational capability until at least 2031, amid cost increases exceeding $6 billion. The U.S. Department of Defense's FY2025 budget allocates $12.4 billion for F-35 procurement and modernization, sustaining production through the mid-2040s despite reduced annual buys in some services.

Instances of Program Reassessment or Delays

Turkey's participation in the F-35 program ended in July 2019 when the United States formally removed it as a partner nation following Ankara's acquisition of Russia's S-400 air defense system, which Washington deemed incompatible with the jet's stealth features and a potential security risk. The expulsion halted Turkey's planned purchase of 100 F-35A aircraft and ended its role in manufacturing rear fuselages at Turkish Aerospace Industries, resulting in the forfeiture of approximately $1.4 billion in invested funds and the relocation of production work to other partners. As of October 2025, Turkey retains sensitive F-35 production equipment but has not been reinstated, with ongoing diplomatic efforts complicated by persistent S-400 possession and U.S. congressional opposition. Canada's F-35 procurement has faced repeated delays and reassessments since the program's inception, with the 2023 agreement for 88 aircraft valued at C$19 billion encountering scrutiny over escalating sustainment costs projected to exceed C$100 billion over the lifecycle and low fleet availability rates below 50%. Political shifts under successive s led to a 2015 cancellation of an interim sole-source , followed by a competitive process favoring alternatives like the Saab Gripen, though Canada rejoined the F-35 program in 2019 as a security partner. As of October 2025, deliveries originally slated for 2026 remain in limbo amid a review weighing industrial offsets and operational readiness concerns, with potential cuts to the order to accommodate lighter fighters. Switzerland selected the F-35A in 2020 for 36 aircraft at a fixed price of 6 billion Swiss francs, overriding a 2020 rejection of the broader budget, but subsequent cost overruns and U.S. restrictions prompted parliamentary reassessment in 2025. Rising unit costs, reported delivery delays averaging 238 days in 2024, and disputes over U.S. tariffs under 25% on imports have fueled calls to cancel or renegotiate, though the affirmed in 2025 that initial deliveries remain on track for 2027 pending review outcomes. Public and political opposition, including activist campaigns dropped in 2022 after legal setbacks, highlights tensions between interoperability with allies and domestic fiscal pressures. Belgium's adoption experienced delivery delays in 2023 when the government withheld acceptance of initial F-35As due to unresolved software issues with the Technical Refresh 3 configuration, pushing back the first two from mid-2023 to late 2023 and subsequent units into 2024. Further technical faults, including a mid-Atlantic issue on one of four jets en route in October 2025, stranded and underscored broader program maturation challenges, though Belgium proceeded with its 34- order and announced plans for additional purchases in July 2025.

Controversies and Strategic Debates

Development Costs Versus Delivered Capabilities

The F-35 program's System Development and Demonstration phase, initiated in the 1990s, experienced substantial cost overruns, with research, development, test, and evaluation expenditures exceeding $55 billion by completion in 2018, far above initial estimates of around $30 billion, due to technical challenges in integrating advanced stealth features and software across variants. These overruns stemmed partly from concurrent development and production, which locked in design flaws requiring costly retrofits, as highlighted in Government Accountability Office analyses. Total program lifecycle costs, encompassing acquisition and 60-year sustainment for over 2,400 planned aircraft, are now projected at $2.1 trillion through 2088, reflecting a 44% rise in sustainment estimates since 2018 amid persistent reliability shortfalls. Flyaway unit costs have declined through , reaching approximately $82 million for the F-35A variant in recent lots as of 2024, excluding engines and retrofits, though full lifecycle costs per approach $100 million when including and upgrades. Block 4 modernization, aimed at enhancing weapons, sensors, and , adds another $16.5 billion in development funding, with delays pushing full operational capability beyond 2029. Critics, including GAO reports, argue these escalations undermine affordability without commensurate schedule adherence, as deliveries averaged 238 days late in 2024. In exchange, the F-35 delivers fifth-generation capabilities centered on low-observable stealth, enabling penetration of advanced air defenses, combined with that integrates data from the radar, Distributed Aperture System, and into a unified picture for the pilot. This fusion provides automated threat geolocation, multispectral targeting, and networked data sharing with joint and allied forces, transforming the aircraft into a force multiplier rather than a standalone dogfighter, as evidenced in operational exercises where it achieves superior over legacy platforms. Unlike fourth-generation fighters, the F-35's internal weapons bays preserve radar cross-section during strikes, supporting multirole missions from air superiority to in contested environments. Assessing value, empirical data from combat simulations and early deployments indicate the F-35's information dominance yields higher mission effectiveness against peer adversaries, justifying costs in scenarios requiring anti-access/area-denial countermeasures, though critiques highlight that unaddressed sustainment inefficiencies erode long-term returns. Proponents note no comparable alternative exists at lower cost for tri-service, multinational , with unit prices now competitive to upgraded fourth-gen jets when factoring total ownership. Independent analyses, such as those from the , underscore that while upfront investments were inflated by program concurrency, the resultant platform's deterrence utility in high-threat theaters outweighs per-unit expenditures for planned fleets.

Reliability Issues and Mission Capability Rates

The F-35 program has faced ongoing reliability challenges, characterized by mission capability rates (MCR)—the percentage of aircraft able to perform all assigned missions—and full mission capable (FMC) rates—the subset fully ready for combat without restrictions—consistently falling short of service-specific targets, which range from 70-80% for MCR depending on variant and operator. From (FY) 2015 to FY2024, all variants (F-35A, F-35B, F-35C) recorded MCR below targets, with FMC rates even further deficient, reflecting issues in condition and sustainment rather than just depot maintenance. Similarly, assessments from 2019-2023 confirmed no variant achieved MCR or FMC goals, attributing shortfalls to deferred , supply chain dependencies, and immature systems like the Autonomic Logistics Information System (ALIS), now transitioning to . Key reliability metrics underscore these gaps: mean flight hours between critical failures (MFHBCF) for the F-35A fell below requirements in FY2023, while F-35B and F-35C were marginally short; maintainability suffered with mean corrective time for critical failures (MCMTCF) across variants exceeding requirements by double or more, showing minimal improvement since FY2015. Operational , incorporating depot and non-mission capable , trended downward over five years ending 2023, below goals, exacerbated by spares shortages, inadequate technical for organic , and heavy contractor reliance—issues compounded by the 's complex stealth coatings, , and software-intensive architecture requiring specialized skills not yet scaled for fleet-wide sustainment. For instance, F-35B MCR reached 59.7% in recent Navy/Marine Corps evaluations, missing the 75% threshold, while full mission for B and C variants hovered below 10% for older airframes, with only newest lots exceeding that minimally. Sustainment costs have risen 44% since 2018 to a projected $1.58 trillion lifetime, partly due to these reliability shortfalls driving higher-than-planned hours and reduced generation rates—DOD now anticipates flying F-35s less than originally estimated, with per-aircraft operating costs at $6.6 million annually for the versus a $4.1 million target. Contributing factors include production quality escapes persisting despite a 63% reduction in such defects from 2016-2023, TR-3 software instability delaying full combat capabilities on 41 aircraft as of FY2024 end (limited to truncated Block 3F version), and depot capacity constraints amplifying non-mission capable status. Positive trends include post-FY2019 gains for F-35A and B via improved spares management, but overall, these issues stem from the program's concurrency of development and production, prioritizing rapid fielding over mature reliability—a causal evident in comparisons to legacy fighters like the F-16, which maintain 80-90% MCR with simpler designs and established .
MetricF-35A (FY2023)F-35B (FY2023)F-35C (FY2023)Requirement Status
MFHBCFBelowSlightly belowSlightly belowShortfall across variants
MCMTCF~2x requirement~2x requirement>2x requirementExceeded, no improvement trend
MCR (2019-2023 avg.)Below targetBelow targetBelow targetNone met goals
DOT&E notes that while 17 of 24 reliability/ goals were met or neared by August 2023, systemic fixes like deployment (phased through 2025) and enhanced training are essential to close gaps, though testing delays for upgrades like TR-3 push operational maturity to FY2026 or later.

Comparisons to Legacy Aircraft and Alternatives

The F-35 incorporates stealth features, such as a low cross-section estimated at 0.001 in frontal aspect, enabling it to evade detection by legacy fourth-generation fighters' radars like those on the F-16 or F/A-18, which lack comparable low-observability . This allows the F-35 to conduct strikes in contested environments where non-stealth aircraft, such as the F-15C, would face higher attrition risks from surface-to-air missiles. In aerodynamic performance, a combat-configured F-35A exceeds fourth-generation peers in sustained speed and climb rate due to its optimized airframe, though it yields in raw to dedicated interceptors like the F-15. Sensor fusion distinguishes the F-35 from legacy aircraft, automatically integrating inputs from its radar, distributed aperture system, and to present fused threat data on a single , reducing pilot workload compared to the siloed sensors on F-16s or F/A-18s. This networking capability extends to sharing real-time data with joint forces, amplifying beyond the standalone operations typical of fourth-generation fighters. However, empirical readiness metrics reveal shortcomings: the F-35A fleet achieved a 51.9% mission-capable rate in fiscal 2023, trailing the higher of mature F-16 and F-15 fleets, attributable to immature sustainment and parts commonality issues across variants. Lifetime sustainment costs, projected at $1.58 trillion through 2088, exceed those of legacy platforms by factors driven by stealth coatings and software-intensive maintenance, prompting debates on cost-effectiveness for high-sortie-rate missions suited to cheaper F-16 upgrades. Flyaway costs for the F-35A, approximately $82 million per unit in recent lots, align with or undercut advanced fourth-generation upgrades like the F/A-18E/F Super Hornet ($80-90 million) and F-15EX ($87.7 million base), while delivering fifth-generation stealth absent in those alternatives. Against European 4.5-generation options like the or , the F-35's all-aspect stealth and integrated sensor suite provide superior survivability in beyond-visual-range engagements, where Rafale's active missiles and warfare excel but falter against low-observable targets. The Russian Su-57, while emphasizing via , exhibits higher observability due to engine design compromises and lags in sensor maturity, rendering it less effective in networked, stealth-centric warfare paradigms. These attributes position the F-35 as a qualitative leap for multirole missions, though procurement decisions in nations like weigh Rafale's combat-proven versatility against F-35's information dominance.

Geopolitical Value and Deterrence Effectiveness

The F-35 Lightning II contributes to geopolitical stability by enhancing interoperability among U.S. allies, enabling networked operations that amplify collective defense capabilities against peer adversaries. Its and stealth features facilitate information sharing across platforms, strengthening deterrence through superior in contested environments. Exports to over a dozen nations, including members and Indo-Pacific partners, signal commitment to mutual security arrangements, often aligning recipients with U.S. strategic priorities amid rising tensions with and . In contexts, the F-35 bolsters conventional and nuclear deterrence against Russian aggression, as evidenced by its first-time leadership in the Steadfast Noon exercise in October 2025, involving 14 countries and simulating nuclear strikes from bases like Volkel Airbase in the . Deployments for have intercepted Russian incursions, with Italian F-35s escorting intruders in recent violations, underscoring its role in restoring deterrence. European operators view the aircraft as foundational for countering anti-access/area-denial threats, extending penetration capabilities beyond legacy fighters. Within the Indo-Pacific, F-35 deployments to and exercises like Talisman Sabre with reinforce U.S. strategy to deter Chinese expansion, with over 300 aircraft projected in the region by 2035 to counter advanced threats. Accelerated acquisitions are urged to address U.S. readiness gaps relative to China's modernization, emphasizing the jet's survivability in high-threat scenarios. Israel's F-35I Adir variant has demonstrated deterrence effectiveness through combat operations, achieving 90% mission readiness during sustained conflicts and conducting suppression of enemy air defenses against Iranian targets in Operation Rising Lion in June 2025. First operational use in 2018, followed by strikes in , Gaza, and , highlights its role as a force multiplier, integrating indigenous systems for deep-strike missions that degrade adversary capabilities without losses.

Accidents and Incidents

Major Flight Mishaps and Investigations

On May 19, 2020, a U.S. F-35A (tail number 12-005053) assigned to the crashed on runway 30 at , , during a nighttime approach. The Investigation Board (AIB) determined the primary cause was the mishap pilot's improper control inputs following a , compounded by inadequate familiarity with the aircraft's automated flight control responses and logic during high sink-rate conditions. The pilot ejected safely prior to impact, sustaining minor injuries, while the aircraft was destroyed, resulting in damages exceeding $100 million. On October 19, 2022, an F-35A from the crashed at , , shortly after takeoff during a routine . The AIB report identified the cause as a initiated by an in-flight generator malfunction, which led to the loss of primary flight displays, subsequent pilot , and departure from controlled flight. Contributing factors included limitations in the aircraft's backup systems and the pilot's delayed recognition of the emergency in . The pilot ejected safely, and the jet was a total loss valued at over $80 million. In a more recent incident on January 28, 2025, an F-35A (tail number 19-5535) from Eielson Air Force Base, Alaska, crashed during takeoff in sub-zero temperatures. The AIB, in its August 2025 report, attributed the mishap to water contamination in the hydraulic fluid, which froze within the nose and main landing gear actuators, preventing proper gear retraction and causing erroneous ground-mode sensor inputs that degraded flight controls. This triggered a loss of aircraft authority, forcing the pilot to eject uninjured as the jet impacted the runway. The event underscored maintenance challenges with hydraulic system purity in Arctic conditions, with the aircraft loss estimated at $110 million. Additional investigations have examined mishaps involving environmental hazards, such as a July 2021 F-35A encounter with from a preceding at , where the AIB cited insufficient spacing and pilot overcorrection as factors in a temporary loss of control, though the jet recovered without destruction. These events, predominantly occurring during training, have prompted fleet-wide reviews of flight control software, maintenance procedures, and pilot training curricula to address systemic vulnerabilities.

Grounding Events and Safety Responses

The F-35 program has experienced multiple fleet-wide groundings and partial stand-downs due to identified safety risks, primarily stemming from engine anomalies, failures, and malfunctions. In June 2017, the U.S. grounded an F-35A squadron at following five reported hypoxia-like episodes where pilots experienced oxygen deprivation symptoms during flight. These incidents traced back to physiological events reported as early as April 2011, totaling 15 by mid-2017, prompting investigations into the aircraft's onboard oxygen generation system (OBOGS) and leading to temporary flight restrictions until mitigations like enhanced monitoring and system tweaks were implemented. A global grounding of nearly all operational F-35s occurred from October 11, 2018, to mid-November 2018, affecting over 280 aircraft across and international fleets, after an F-35B crash off on September 28, 2018, revealed a faulty tube in the F135 engine prone to cracking under high-pressure fuel transfer conditions. The Pentagon's Joint Program Office mandated inspections and replacements of the affected fuel lines, with responses including redesigned tubing materials and rigorous non-destructive testing protocols to prevent fatigue failures, restoring full flight operations after verification on over 500 engines. In December 2022, following an F-35B crash in during a post-maintenance check flight, the program grounded all F-35s with fewer than 40 flight hours due to a similar high-pressure tube vulnerability in low-time engines, exacerbating concerns over quality in early production lots. Safety responses involved accelerated tube inspections and a shift to more durable alloys, though the incident highlighted ongoing issues in engine components from . By July 2022, the U.S. had grounded most continental U.S.-based F-35As due to deficiencies in Martin-Baker ejection seat cartridge-actuated propeller devices, which risked failure during ejections at low altitudes or speeds; this was resolved through seat hardware retrofits and pilot briefings on adjusted ejection envelopes. The September 17, 2023, incident where an F-35C went untraceable for over 30 minutes due to a latent malfunction and pilot communication failure prompted a broader U.S. Marine Corps-wide stand-down from September 18-19, 2023, encompassing all fixed- and rotary-wing assets, not limited to F-35s. Commanders conducted assessments, procedural reviews, and refreshers on mode selector usage and protocols, with F-35-specific software patches deployed to enhance automatic backup systems and prevent similar disorientation events. These groundings underscore persistent challenges in integrating complex and propulsion systems, with responses emphasizing empirical testing and iterative hardware-software fixes over rushed operational tempo.

Lessons Learned and Mitigation Measures

The U.S. Air Force's Accident Investigation Boards (AIBs) have systematically analyzed F-35 mishaps to identify root causes and implement targeted mitigations, emphasizing hardware reliability, procedural safeguards, and pilot training. In the July 8, 2025, Eielson AFB F-35A crash, the AIB attributed the nose landing gear retraction failure to water-contaminated freezing during extreme cold weather operations, resulting in the aircraft's destruction valued at $196.5 million; subsequent mitigations included enhanced pre-flight fluid purity checks and cold-weather maintenance protocols to prevent contamination ingress. Engine durability emerged as a critical lesson from early incidents, such as the June 2015 Eglin AFB F-35A mishap, where a third-stage forward fan blade fracture in the engine caused and fire; this prompted mandatory ultrasonic inspections of fan blades across the fleet and material coating refinements to mitigate susceptibility. Pilot-aircraft interface deficiencies have driven software and training upgrades, as evidenced by the May 19, 2020, Eglin AFB F-35A overrun, where reliance on the Speed Hold mode combined with latency contributed to the pilot's failure to arrest landing rollout; mitigations involved software blocks in Block 3F upgrades to restrict incompatible modes during approach and expanded simulator scenarios for alternate cross-check techniques. Air data system vulnerabilities were addressed following the July 2022 Hill AFB F-35A crash, where erroneous inputs triggered uncontrolled flight during approach, linked to insufficient landing spacing in formation and uncommanded pitch oscillations; responses included refined air data algorithms in subsequent software loads and procedural mandates for increased separation distances in low-visibility or conditions. Broader incidents, including the 2023 F-35B "zombie" flight after pilot ejection due to a latent fuel exhaust nozzle failure, underscored the need for automated termination protocols; this led to enhancements and ground control integration tests to enable remote disablement of unmanned , reducing risks to populated areas. Ejection risks for lighter pilots, identified in 2015 Martin-Baker US16E seat testing showing up to 98% fatal injury probability below 135 pounds, resulted in operational weight restrictions and seat cushion modifications prior to full-rate production clearance in 2019. Collectively, these measures—drawn from over a dozen Class A mishaps since —have incorporated fleet-wide groundings for inspections, iterative Block 4 upgrades integrating failure mode redundancies, and joint service safety stand-downs, such as the Marine Corps-wide pause after the 2023 disappearance incident to audit upload procedures.

Performance Specifications

Baseline F-35A Characteristics

The F-35A Lightning II is the conventional takeoff and landing (CTOL) variant of the F-35 family, optimized for air force operations with internal weapons bays, stealth features, and advanced sensor fusion for multirole missions including air superiority, ground attack, and intelligence, surveillance, and reconnaissance. It accommodates a single pilot in a tandem cockpit with a panoramic helmet-mounted display system providing 360-degree situational awareness. The aircraft measures 51.4 feet (15.7 meters) in length, 14.4 feet (4.38 meters) in height, and has a of 35 feet (10.7 meters), with a wing area of 460 square feet (42.7 square meters). Empty weight is approximately 29,300 pounds (13,290 kilograms), while reaches 70,000 pounds (31,800 kilograms). Internal capacity totals 18,250 pounds (8,278 kilograms), enabling a combat radius exceeding 590 nautical miles on internal fuel for air-to-ground missions. Propulsion is provided by a single F135-PW-100 engine delivering 43,000 pounds of thrust with . Maximum speed is Mach 1.6 (approximately 1,200 at ) with full internal weapons load. The F-35A achieves a service ceiling of 50,000 feet and sustains 9g maneuvers, supported by controls and for enhanced agility.
CharacteristicSpecification
Crew1
51.4 ft (15.7 m)
35 ft (10.7 m)
14.4 ft (4.38 m)
Empty Weight29,300 lb (13,290 kg)
Max Takeoff Weight70,000 lb (31,800 kg)
Internal Fuel18,250 lb (8,278 kg)
F135-PW-100
Thrust (Afterburner)43,000 lbf
Max SpeedMach 1.6
Combat Radius (Internal)>590 nmi (air-to-ground)
Service Ceiling50,000 ft
G-Limits+9.0

Inter-Variant Performance Differences

The F-35A, F-35B, and F-35C variants share core performance attributes such as a maximum speed of Mach 1.6 and comparable stealth characteristics due to identical avionics, sensor fusion, and low-observable design principles, but diverge in fuel capacity, range, payload accommodations, and structural limits tailored to their respective missions. The F-35A, optimized for conventional runways, benefits from the highest internal fuel load of approximately 18,500 pounds, enabling a combat radius exceeding 590 nautical miles on internal fuel alone. In contrast, the F-35B's short takeoff and vertical landing (STOVL) capability necessitates a lift fan and roll-post burner, increasing empty weight and reducing internal fuel to about 13,100 pounds, which limits its combat radius to over 450 nautical miles. The F-35C, designed for carrier operations, incorporates larger wings for improved low-speed handling and control during launches and arrested recoveries, along with reinforced and a tailhook, resulting in greater empty weight but enhanced fuel capacity of around 19,750 pounds for extended maritime missions. These adaptations yield a combat radius comparable to or slightly exceeding the F-35A's in certain profiles, though specific figures vary by mission assumptions. Maneuverability differs notably in g-limits: the F-35A sustains up to 9g maneuvers, while the F-35B is restricted to 7g and the F-35C to 7.5g, reflecting trade-offs for vertical lift and carrier stresses. Weapon payload capacities are similar across variants, with all capable of exceeding 18,000 pounds total (internal and external), but internal configurations vary; the F-35B's bays are shortened to accommodate the lift system, precluding certain larger ordnance like full-length JDAMs that fit in the A and C models. The F-35C's enlarged bays support over 5,000 pounds internally, optimizing stealthy strikes from carriers. Overall, these differences prioritize mission-specific basing flexibility over uniform performance, with the F-35A offering superior and range efficiency for land-based operations, the F-35B enabling austere deployments at the cost of endurance, and the F-35C emphasizing naval persistence.
VariantInternal Fuel (lb)Combat Radius (nm, internal fuel)Max G-LimitKey Trade-Off
F-35A~18,500>5909gHighest agility, conventional ops
F-35B~13,100>4507gSTOVL capability reduces fuel/range
F-35C~19,750~500-600 (profile-dependent)7.5gCarrier adaptations enhance endurance

Empirical Data on Stealth and Combat Metrics

The F-35's low-observability features, including shaped , radar-absorbent materials, and internal weapons carriage, have been validated through and operational evaluations, though exact radar cross-section (RCS) figures for operational frequencies remain classified by the U.S. Department of Defense. In and scaled-model tests conducted during development, the design achieved reductions in RCS compared to fourth-generation fighters, enabling reduced detection ranges by ground and airborne radars. Empirical assessments from exercises indicate the F-35's frontal RCS is estimated at around 0.001 square meters—five orders of magnitude lower than legacy aircraft like the F-16—allowing it to approach defended targets undetected until short ranges, as evidenced by its ability to suppress enemy air defenses without being engaged in simulated high-threat scenarios. In the Red Flag 17-1 exercise held at from January 23 to February 10, 2017, eight U.S. F-35A amassed 145 simulated air-to-air kills against seven losses, yielding a 20.7:1 kill ratio against aggressor forces equipped with advanced fighters and electronic warfare capabilities. This performance stemmed from the jet's integrated sensors, including the radar and , which provided pilots with fused data superior to opponents, often detecting threats at beyond-visual-range distances while remaining undetected themselves. Subsequent Red Flag iterations, such as 19-1, replicated high kill ratios exceeding 15:1, with the F-35 acting as a force multiplier by cueing legacy to targets. Israeli Air Force F-35I Adir variants have logged over 400 combat sorties since achieving initial operational capability in December 2017, including deep strikes into and , with zero aircraft losses attributed to enemy action as of 2025. In operations against Iranian-backed targets, the F-35I penetrated integrated air defense systems undetected, delivering precision munitions and intelligence without triggering launches, as confirmed by Israeli military statements. During the , 2024, strikes on Iranian missile facilities, F-35Is operated in contested airspace, evading coverage and achieving all objectives without attrition, underscoring the platform's stealth-enabled in peer-level threats.

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