The Lockheed F-35 "Lightning II" (unofficially nicknamed the "Panther") is a 5th Generation strike fighter development of the United States that incorporates new and learned stealth technology and practices with advanced computer processing and systems through a modular approach. The original project goal (it began as the "Joint Strike Fighter") was to develop a single airframe capable of serving the multiple armed services of the U.S. Department of Defense - namely the United States Air Force (through the 'F-35A'), the United States Navy (through the carrier-capable 'F-35C'), and the United States Marine Corps (through the VTOL-capable 'F-35B'). Other major global players emerged in the British Royal Air Force (RAF) and Royal Navy (RN)
As such, the F-35 program has produced three related yet distinct airframes to reflect respective operator uses with each offering centered around the same single-engine, single-seat approach. Despite differences between production models, the aircraft remains a supersonic (Mach 1.0+ capable) performer with inherently lethal strike capabilities unmatched by any other modern over-battlefield platform.
Despite its appearance mimicking that of Lockheed's other fighter project, the F-22 'Raptor', the F035's role is primarily that of strike with air-to-air as secondary. The F-22 is billed as an air superiority fighter through-and-through. The F-35 will be called upon to undertake attack missions through the use of precision-guided drop bombs, conventional drop bombs, and air-launched missiles while also being capable of advanced airborne real-time reconnaissance and radar-suppression - all this while retaining air-to-air capabilities.
The F-35B variant is the most distinct of the trio, for it provides the pilot and warplanners with a platform with qualities akin to the classic BAe AV-8 "Harrier" Vertical Take-Off and Landing (VTOL) jet aircraft. The Lockheed B-model does this design one better by making it the first supersonic-capable VTOL design in aviation history.
From the outset, the F-35 end-product was intended as an "affordable" fighter platform which led to the development of a singular airframe capable of completing multiple tasks to suit customer requirements. As such, the finalized fighter is afforded a complex Battlefield Management System (BMS) allowing it to receive and track real-time information, in turn allowing the pilot and aircraft to react accordingly all the while transferring pertinent information to other allied forces. The aircraft provides for simplified maintenance regimens with attention paid to the sensitive stealth components and skin coating. Throughout its design phases, the F-35 has incorporated an array of radar-defeating/absorbing measures that include a specialized mix of construction materials, surface coatings, angular edges, and internally-based sensors to minimize the aircraft's profile to radar from most any direction.
The F-35 program evolved to become an international effort beyond the commitments of the United States and the United Kingdom and have included Australia, Canada, Denmark, Italy, Netherlands, Norway, and Turkey to varying degrees. Each nation is expecting to operate the F-35 platform in number at some point and each player is rated by partner levels in the development (the UK is a top partner as a 'Level 1' contributor while Italy and the Netherlands are 'Level 2' partners and Canada, Turkey, Australia, Norway, and Denmark are 'Level 3' partners. Israel and Singapore signed on as "Security Cooperative Participants" (SCP).
At the outset of the program, the various involved air services planned for the following quantities of F-35 fighters: USAF (1,763); USN/USMC (680); RAF/RN (138); Italy (131); Netherlands (85); Turkey (100); Australia (100); Norway (56, up from the original 48 as of June 2009); Denmark (48); Canada (80). Norwegian F-35s will be replacing an fleet of aging F-16 'Fighting Falcons' while Italian F-35s see final assembly at its Cameri Air Base.
Cost estimates for a single F-35 aircraft unit in original FY2002 program dollars were as follows: F-35A ($40 million+); F-35B ($60 million+); F-35C ($60 million). Delays and natural project progression have inevitably resulted in much higher per-unit costs: F-35A $82.4 million; F-35B ($108 million); F-35C ($103 million).
The Joint Strike Fighter (JSF) Program
The Joint Strike Fighter program was started on November 16th, 1996 as a U.S. attempt to develop a "next-generation" combat airframe capable of replacing a variety of dedicated fighter and fighter-bomber types then in the U.S. war-making inventory. The new design would have to succeed such proven performers as the Lockheed F-16 'Fighting Falcon', the Fairchild Republic A-10 'Warthog', the carrier-based Boeing F/A-18 'Hornet', and the McDonnell Douglas AV-8B 'Harrier II' (the latter also covering the British Harrier developments in the attack-minded Harrier GR.Mk 7 and GR.Mk 9). No small task considering the respective successes found by each aircraft throughout the world for time in aviation history.
Replacing the Cold War Heavy-Hitters
By this point, the Lockheed (formerly General Dynamics) F-16 "Fighting Falcon" had proven itself in countless conflicts beginning with actions in the Middle East in 1981. The F-16 was a lightweight aircraft equally capable of air superiority and ground strike alike while maintaining a healthy capability in mounting a variety of munitions to suit field requirements. This multi-faceted performer went on to become a staple of the American air fleet as well as its allies across South America, the Middle East, Europe, and the Pacific. Production of this fine warplane went on to reach over 4,600 examples with the first introduced in 1978.
The Fairchild Republic A-10 "Thunderbolt" was a highly unique, Close-Air Support (CAS) aircraft charged with the destruction of enemy armor at low-speed / low-altitude. The system was built from the outset for pilot and system survival and resulted in a "flying tank" complete with cockpit armoring, raised engine nacelles, and the inherent ability to withstand a good deal of battlefield punishment. The aircraft could fly on one engine if need be and holds the capability to carry an impressive weapons load consisting of missiles (air-to-air and air-to-ground types) and bombs (conventional and guided types). However, the A-10 has always been noted for its nose-mounted, 7-barreled 30mm "Avenger" Gatling gun which makes short work of Cold War-era armor. The single-seat A-10 platform was debuted in 1977 and ultimately produced in 715 examples including a two-seat Forward Air Control (FAC) version.
The Navy-minded F/A-18 Hornet was derived from the YF-17 "Cobra" lightweight demonstrator, a design that lost out to a design that would eventually become the General Dynamics F-16 "Fighting Falcon" for the USAF and others. The U.S. Navy, however, found interest in the losing aircraft and the revised (and dimensionally larger) F/A-18 "Hornet" was selected to replace the aging fleet of Grumman F-14 "Tomcat" swing-wing fleet defenders, Grumman A-6 "Intruder" strike platforms, and Vought A-7 "Corsair II" attackers on all U.S. carriers. The product was developed as a multirole performer equally capable of taking on the air superiority role of the Tomcat while providing the strike capability of the Intruder and Corsair II. Like the F-16, the F/A-18 "Hornet" has gone on to prove its worth the world over since series adoption in early 1983 and has further been evolved into the two-seat F/A-18E/F "Super Hornet" variant.
The McDonnell Douglas AV-8B Harrier II (and its British counterparts the GR.7 and GR.9) were modernized versions of the original Hawker Siddeley Harrier VTOL multi-role, close-support "jump" jets. The Americanized AV-8B was developed exclusively for the U.S. Marine Corps "going it alone" while the British pursued other aircraft interests of the period, eventually returning the USMC program to become a junior partner. The history of the Harrier made it one of the most dangerous and complicated aircraft to fly but also made it one of the most unique battlefield components - a jet with fighter-like performance wrapped around helicopter-like capabilities.
It was this impressive stable of Cold War developments that the Joint Strike Fighter project sought to replace.
The F-35 was the aircraft born out of the U.S. JSF and, for the period of five years, it faced off against the competition in as the "X-35" against the Boeing "X-32". The program called for construction of two Concept Demonstration Aircraft (CDA) and engineers relied heavily on computer design work to better predict data related to the CDA aircraft. The final proposal capped by pages of proposals with promises detailing the aircraft maintenance requirements and construction needs. The winner of the program was eventually decided on October 26th, 2001.
Though both aircraft seemed to fit the requirements, the Lockheed submittal was selected ahead of Boeing's in that it consistently bested the Boeing design enough to earn the victory and was seen as a "lesser" financial risk in the long run. The X-32 also used a more conventional "vectored-thrust" approach, similar to that as employed by the Harrier, to complete its vertical and take-off approaches. A third proposal, this by a Northrop Grumman/McDonnell Douglas team, was to employ a rather interesting "Lift-Plus-Lift" / cruise methodology similar to that as found on the Soviet Yakovlev Yak-38 "Forger". The Lockheed team settled on a dedicated lift-fan system positioned at center mass just aft of the cockpit coupled with a rotating rear engine exhaust nozzle to accomplish the same balanced result - with both propulsion units deriving lift power from the single engine. Lockheed's patented lift fan, though a new and untested component, was deemed a more reasonable long-term approach. The lift-fan concept held some distinct advantages over that of the X-32's thrust-vectoring system in that the lift fan offered cooling for the downward-thrust air, meaning that the chance of hot exhaust gasses re-entering the engine was minimized. Additionally, the space required for the lift-fan drive system was a benefit to the proposed X-35A and X-35C conventional fighter offshoots planned for its removal meant more internal fuel stores could be carried - and therefore operational ranges increased. Since the USMC was more interested in a short-range, quick-react aircraft to begin with, range was a limitation that could be overlooked on the STOVL version of the X-35 (X-35B).
Securing the X-35 contract for Lockheed was no small feat and there was plenty of risk to be had. With all options exercised, the X-35 program (and subsequent F-35 production phases) could net the firm some $200 billion dollars. Engine maker Pratt & Whitney was also onboard as the primary engine supplier, receiving a $4 billion dollar contract for its part in the powerplant development and production. Not content to side idle, the British stepped in and invested $2 billion into the project with the ultimate hope of securing the country's first 5th generation - and first stealth - fighter.
The project also included major contributions from Northrop Grumman and British Aerospace (BAe).
The production F-35s were born out of the three X prototypes - the first being the X-35A produced out of the Skunk Works facility at Palmdale. The X-35A completed its first flight on October 24th, 2000, and was then transferred to Edwards Air Force Base for rigorous trials including in-flight refueling runs and beyond-the-speed-of-sound flights. After 27 flight tests concluded on November 22nd, 2000, the vehicle was delivered back to Palmdale for conversion into the X-35B STOVL variant prototype. X-35C actually became the second aircraft of the series constructed while the X-35A-X-35B conversions were taking place. Serving as a "back up" to the more complicated X-35B development, the X-35C was made ready to accept the lift-fan assembly should the X-35B find itself lost to accident or some other major complication. The first production F-35 Lightning II achieved first flight on December 15th, 2006. The first F-35A wrapped up flight-testing at Edwards Air Force Base on October 23rd, 2008. Supersonic flight was achieved soon after on November 13th, 2008.
X-35B achieved first flight on June 24th, 2001, and accomplished a complete, sustained hover cycle, eventually covering 18 total vertical take-off operations and no less than 27 hover landings. The production STOVL F-35B began its flight-testing phase in 2008. The first F-35B (STOVL variant) achieved first-flight on June 11th, 2008 and the second F-35B (known as "BF-2") completed its first flight on February 25th, 2009. Its first aerial refueling exercise (via probe-and-drogue) was completed on August 13th, 2009.
The carrier-capable X-35C went airborne for the first time on December 16th, 2000 and moved on to a series of rigorous mock carrier landings to test out the validity of the modified airframe. The X-35C proved a pleasant aircraft to fly and excelled in the low-level, low-speed approaches the US Navy was looking for in their new combat aircraft. The X-35C completed testing by way of 73 total flights on March 11th, 2001 and the production F-35C (USN variant) was revealed on July 28th, 2009 with an expected first-flight sometime before the end 2009.
The F-35 test program completed its 100th flight on June 23rd, 2009.
As initially planned, the F-35B for the USMC was expected to be delivered sometime in 2012 - the earliest of the three variants- while the USAF has the expectation of deliveries of its F-35A model sometime in 2013. The US Navy's F-35Cs were expected to be delivered in 2015.
All told, the lifespan of the airframe was estimated to survive at least beyond 2030 and reach into the 2040s.
As completed, the F-35 features an Electro-Optical (EO) Distributed Aperture System (DAS) that simultaneously informs the pilot of the battlefield situation from every angle of his aircraft. The aircraft is able to single out and coordinate enemy aircraft in the sky as well as air-to-air and surface-to-air missile launches directed against the F-35. Explosions on the ground also signal detection within the aircraft. High levels of automation are implemented in both the STOVL and conventional landing variants to help ease workflow. The aircraft also supplies enhanced pilot vision for both day and night sorties. The system was developed by Lockheed Martin Missiles and Fire Control with Northrop Grumman Electronic Systems.
Lockheed Martin Missiles and Fire Control and Northrop Grumman Electronic Systems also geared up to provide the F-35 pilot with an all-new Electro-Optical Targeting System (EOTS) to supply the F-35 pilot with the ability to detect and track targets from greater ranges with a high level of accuracy. This makes the Lightning II one of the most deadly combat aircraft in the skies. The EOTS sits at the underside portion of the nose assembly.
Stealth lessons learned since the flying days of Lockheed's F-117 "Nighthawk" stealth fighter have been evolved to a high degree in the F-35 Lightning II: the engine nozzle is "stealth-friendly" and axisymmetric by design to further the aircraft's anti-radar characteristics while maintaining the smallest possible signature and overall profile.
Northrop Grumman Space Technology produced the modular F-35 avionics suite: data-sharing allows the pilot to relay information to air- and ground-based allies as needed in real-time. The Lightning II is arranged with a satellite data-link which gives it Beyond-Line-of-Site (BLOS) communications as well as being web-enabled. The communications suite, developed with the program's foreign partners, is a robust, adaptable system.
The Lightning II is completed with a multi-mission AN/APG-81 series Active, Electronically-Scanned Array (AESA) radar developed by Northrop Grumman Electronic Systems. The system supplies the F-35 pilot with a heightened level of situational awareness, able to detect, track and engage targets on land, on water, or in the air at far-reaching ranges. The radar can be set to act as a passive radar receiver.
The Distributed Infra-Red System (DIRS) is a collection of six internal sensors mounted about the aircraft airframe and provide an image of the aircraft's surroundings directly into the advanced helmet donned by the pilot. This technology will allow the pilot to "see through" his aircraft at the world around him in infra-red, providing full 360-degree situational awareness.
The inlets of the F-35 engine ports are diverterless fixtures and helps producing a lighter overall assembly with little-to-no moving parts. These intakes are identifiable by their bulge along the fuselage side to spill-off turbulent boundary layer air that builds up along the sides of the intake lips.
As with most modern combat warplanes, a "Helmet Mounted Display System" (HMDS) is featured in the F-35. Developed by Vision Systems International LLC, the new helmet is one of the most advanced systems in service today, negating the need for the cockpit to fit a conventional Heads-Up Display (HUD) system. This unit, instead, delivers critical mission and systems data directly to the helmet visor. The aircraft need not be facing the target to track and engage thanks to this special setup. The cockpit will be dominated by a single large 8"x20" panoramic Multi-Function Display System (MFDS) fitted across the top of the instrument panel. The projection display is powered by fast-processing capabilities and relays real-time information and high-resolution motion imagery to the F-35 pilot. The cockpit also supports Direct Voice Input through a speech recognition system complete with a Martin-Baker US16E ejection seat (common across all three F-35 production variants). Flight control is through a conventional HOTAS setup with a left-side throttle and a right-side flight stick.
Adaptability of the onboard systems is key and, as such, is highly-configurable to the mission at hand - be it air superiority or ground strike.
Primary propulsion for the F-35 is supplied by a single Pratt & Whitney F135 afterburning turbofan engine. A second powerplant - the upgraded F136 - was, at one point, in development but this under a joint General Electric and Rolls-Royce branding initiative. The engine's development was ended in December of 2011.
The F135, at its core, is an afterburning turbofan engine delivering 28,000lbf on dry thrust with up to 43,000lbf on full afterburner. The engine resides within the middle-rear portion of the fuselage. Performance results net the F-35 a maximum speed of Mach 1.61 and a ceiling of over to 50,000 feet. The aircraft's rate-of-climb is classified and G-limits vary based on variant model with the A-model receiving a 9g limit rating.
The F-35B production model makes use the Lockheed Martin-patented Shaft-Driven Lift Fan (SDLF) to achieve vertical flight. The Lockheed lift-fan was built by Rolls-Royce Corporation of Indiana and the entire component is made up of the fan itself, a clutch, two Roll Posts (wing-mounted thrust nozzles for roll control), and the drive shaft connecting the lift-fan to the powerplant. This works in conjunction with the Three Bearing Swivel Module (3BSM) - the thrust vectoring nozzle at the tail of the aircraft. The lift-fan is powered by a two-stage turbine on the engine and works in conjunction with the downward-vectored rear exhaust port and Roll Posts to achieved a balanced lift cycle. The lift fan can generate up to 20,000lb of lift (almost half of the vertical flight thrust), also providing cooling for down-drafting air compared to previous STOVL offerings. Air flow through the fan is controlled via variable inlet guide vanes.
The Variants - From A-to-C
The F-35 has been developed into three distinct variants for respective operators. This allows for up to near-80% commonality of parts between the three primary airframe types. The avionics suite is near-100% common across the three airframes. Some parts used in the construction also closely resemble others and are referred to as "cousins" in commonality. The program also stressed that the current F-35 build to be easily-upgradable than previous mounts as new technology comes online, again helping to drive down long term costs of operating, maintaining and upgrading the machine.
The F-35A is the Conventional Take-Off and Landing variant ("CTOL") primarily for use with the United States Air Force though also representing the base export model. The F-35B is a Short-Take-Off and Vertical Landing (STOVL) variant primarily developed for the United States Marine Corps and Royal Air Force / Royal Navy services. The F-35C is another conventional model, though "navalized" for use on aircraft carriers with CATOBAR (Catapult Assisted Take-Off But Arrested Recovery) capability - exclusively developed for the United States Navy.
The F-35A sports an unrefueled range of 1,700 miles without external fuel tanks and is the only version armed through a fixed internal 25mm GAU-22/A automatic cannon. Two weapons bays are built into the fuselage while external hardpoints can be fitted for increased ordnance-hauling. Air superiority armament is centered around a pair of AIM-120C "AMRAAM" medium-range air-to-air missiles and ground-attack is fulfilled through carrying a pair of 2,000lb GBU-31 "JDAM" precision-guided bombs. The aircraft also supports the carrying of up to 8 x GBU-38 drop bombs as well as current generation TV/laser-guided air-to-surface missiles, guided bombs, and munitions-dispensing bombs. External weapons pylons are optional for sorties not requiring stealth.
Overall ordnance-carrying is limited to will be limited to 18,000lb. Structurally, the A-model features a wing span of 35 feet with an overall length of 50.5 feet and a wing area of 460 square feet. Internal fuel is listed at 18,498lb.
The STOVL F-35B
The F-35B is noted as the first aircraft of its kind to successfully combine the benefits of stealth technology with the benefits of STOVL capabilities. This makes the F-35B unique amongst any aircraft in history and allow the fighter to land and take-off from virtually any surface including moving warships and unprepared / rough airfields and even roads. This further allows the F-35 to operate close to the front lines and deliver potent payloads against entrenched, or advancing, enemy forces with little limitation to operational range. Inherent range of this F-35 variant is near-900 miles on internal fuel alone.
Standard armament of B-models is 2 x AIM-120C "AMRAAM" medium-range air-to-air missiles for self-defense with ground-attack satisfied by 2 x 1,000lb GBU-32 "JDAM" guided bombs. Like the F-35A, the F-35B makes use of internal weapons bays for ordnance. Additional munitions options include air-to-surface missiles, munitions dispensers, 6 x GBU-38 bombs and guided bombs. The 25mm GAU-22A Gatling cannon is installed as an external "stealthy" pod to help maintain the aircraft's low radar signature. As in the F-35A, the F-35B can also make use of optional underwing external hardpoints to expand upon its mission lethality. Overall ordnance-carrying capability is limited to 15,000lb.
The F-35B is the most unique of the three F-35s offered as it incorporates the lift fan system detailed above. The fan jumps into action when the pilot sets the aircraft into vertical flight mode for either take-off, hover, or landing actions. The lift-fan works in conjunction with the positional aft-thruster duct which angles itself downwards automatically to provide thrust when in the vertical. The lift-fan acts as a counter-balance for the power emitted from the rear jet exhaust while also supplying cooler air into the hot jet wash being generated by the engine nozzle.
The engine powers the lift fan via a drive shaft from the front of the engine and twin Roll Posts control balance and rolling in much the same way the Harrier's vertical flight "puffer" jets worked through its ducted wings and fuselage thruster points. When the lift fan is in action, a pair of dorsal and ventral doors are opened. Another set of panels just aft of the lift fan is also opened to provide the needed mass flow to the auxiliary engine - many moving parts are required to work in unison for the F-35B. The primary customer of the F-35B is the USMC, Royal Air Force, Royal Navy, and the Italian Navy. The Royal Air Force and Royal Navy have already built up a resume of "jump" jet successes through operation of the Cold War-era "Harrier".
The F-35B features a wingspan of 35 feet, a fuselage length of 50.5 feet and a wing area of 460 square feet. Internal fuel is listed at 13,326lb.
The Navalized F-35C
The navalized F-35C is the U.S. Navy's first stealth aircraft - past attempts came up fruitless through endeavors such as the McDonnell Douglas/General Dynamics A-12 "Avenger II". As a navalized version of the base F-35, the F-35C is launched via steam catapults already serving 4th Generation fighter aircraft such as the F/A-18 "Hornet" and retrieval is made via conventional arrestor hook-and-wire. The F-35C sports a revised (twin-wheeled), and reinforced, undercarriage and internal structure for the rigors of carrier operations as well as larger control surfaces for better low-speed, low-level performance. Folding wing tips also differentiate this model from the others.
Range is out to 1,200 miles on internal fuel alone. Like the other F-35s in the series, the F-35C also makes use of the AIM-120 "AMRAAM" medium-range air-to-air missile as well as 2 x 2,000lb GBU-31 "JDAM" guided bombs. 8 x GBU-38 bombs also figure into this Lightning II's forte and all ordnance is stowed within internal bomb bays. Additional armament includes current in-service air-to-surface guided missiles, conventional bombs, munitions dispensers, and guided bombs. Ordnance-carrying capability is 18,000lb. Like the F-35B, the F-35C also mounts its 25mm GAU-22A series cannon in an external pod fitting. Measurements of the F-35C include a span of 43 feet, a length of 50.8 feet and a wing area of 620 square feet. Internal fuel is listed at 19,624lb.
Though the F-35 has an appearance akin to Lockheed's other 5th generation product (the F-22 "Raptor") it is inherently a wholly new fighter design with a different over-battlefield purpose. It is allowed to be dimensionally smaller through its fitting of a single Pratt & Whitney engine (which reduces straight-line performance compared to the F-22) though it is more refined for the ground attack role - comparable in scope to the F/A-18 "Hornet" and the F-16 "Fighting Falcon".
The fuselage features angular sharply-tapered edges. The cockpit is situated behind a short nose assembly housing the radar and interestingly sports a forward-hinged two-piece canopy. Seating is for a single pilot and no HUD is featured in the cockpit. Intakes straddle either side of the forward fuselage and are angled inward to better promote stealth. The wing mainplanes are large-area, high-mounted members with greater sweep featured along the leading edge and less sweep along the trailing edge. Wings are clipped at their tips set near midships. The split intakes feed the single engine buried in the aft section of the fuselage, the jet pipe terminating in a single exhaust ring. The empennage consists of a pair of outward-canted vertical tail fins while the all-moving horizontal planes are seated (and extended past) the exhaust port. The undercarriage is retractable and made up of two main single-wheeled landing gear legs recessing into the fuselage sides and a single-wheeled (variant dependent) nose landing gear leg recessing forwards under the cockpit floor. Another defining characteristic of the F-35 is the lack of conventional externally-mounted probes and vanes (with the exception of the nose-mounted one), these being installed internally for stealth.
Standard armament for the F-35A production model is the GAU-22/A four-barrel 25mm cannon with 180 rounds afforded. The F-35B and F-35C also feature this weapon though through an external mounting and given 220 rounds. The pod itself sports stealth designing to keep the signature of the F-35 airframe in check. To comply with its stealth requirements, the F-35 typically houses its primary ordnance in internal bomb bays while six optional external underwing pylons provide the bulk of the weapons payload carrying capability (three stations to a wing with the outboard-most stations reserved for the AIM-9X Sidewinder missile).
Because of the F-35's international appeal, the aircraft is capable of fielding some foreign-borne weapon systems available in the UK, Israel, and the NATO arsenal.
The F-35 "Lightning II" is the spiritual successor to the Lockheed P-38 "Lightning" - the classic ace-making, twin-boom, propeller-driven design of World War 2.
The F-35 is in direct competition with several prominent 4.5th Generation Fighters around the world, namely the Boeing F/A-18 "Super Hornet", the French Dassault "Rafale", the Eurofighter Typhoon, the Saab JAS.39 "Gripen", the Sukhoi Su-35, and the Mikoyan MiG-35. Several nations have bypassed the hefty price tag of the F-35 in favor of a still-modern, though more budget-friendly solution.
The Israeli F-35I "Adir"
The Israeli Air Force (IAF) version of the F-35 is designated as F-35I and recognized locally as the "Adir". The Israeli government received permission to integrate Israeli-centric software and weapons system into the F-35 platform to satisfy local requirements. Part of the integration is the Rafael "Python-5" and "Derby" Air-to-Air Missiles (AAMs) as well as the "Litening 5" series targeting pod. The F-35I fleet, built to the Israeli standard, reached IOC in 2017.