Lockheed Martin F-35 Lightning II

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Lockheed Martin F-35A Lightning II
27607444415 4b8b044d7c o.jpg
RoleMulti-role fighter
Crew1 (in Martin-Baker US16E ejection seat)
First FlightDecember 15, 2006 (F-35A AA-1)
Entered ServiceIOC 2016 (US Marine Corps)
Number builtin production
ManufacturerLockheed Martin
Length15.37 m50.43 ft
Wingspan10.65 m34.94 ft
Height5.28 m17.32 ft
Wing area42.7 m²460 ft²
Empty13,302 kg29,300 lb
Internal fuel8,278 kg18,250 lb
Maximum takeoff weight27,200 kg59,966 lb
Capacity18,000 lbs weapons payload
Enginesone Pratt & Whitney F135 turbofan engine
Thrust178 kN+ (each)40,000+ lbf (each)
Maximum speed1,093 km/h1,200 mph
Combat radius, internal fuel, with two 2,000 class bombs and 2 AIM-120 AAMs carried internally1,111 km590 nm [1]
Service ceiling15,240 m50,000 ft
Rate of climbm/minft/min
AvionicsNorthrop Grumman AN/APG-81
ArmamentOne General Electric GAU-12 Equalizer 25 mm gun; air-to-air: AIM-9X Block II and AIM-120 AAMs; air-to-ground: JDAM, Paveway, SDB and WCMD series PGM, B61 Mod 12 nuclear weapon.



The F-35 Lightning II is a fifth generation multi-role fighter under development to perform ground attack, reconnaissance, and air defense missions with stealth capability. The F-35 has three main models: the F-35A conventional takeoff and landing variant, the F-35B short take off and vertical-landing variant, and the F-35C carrier-based variant. The F-35A is scheduled to replace US Air Force and international F-16, the F-35B will replace US Marine Corps and Royal Air Force AV-8B Harrier IIs and the F-35C will replace US Navy, Royal Canadian Air Force and Royal Australian Air Force F/A-18A/B/C/D Hornets.

Operational requirement

Main requirements for the F-35A were 600 nm combat range carrying two 2,000 class bombs (such as the GBU-31/B JDAM) and two AIM-120 internally, ensuring the stealth characteristics. Generally speaking, this is comparable to the range/payload of a F-16C Block 50 with two external fuel tanks ans similar external weapons, of course making the F-16 non-stealthy. As a result, the F-35A is a fairly large and heavy aircraft: its 13 tons empty weight is comparable to that of the F-15C Eagle and nothing near the F-16C-CF-50s 7,5 tons. Equally, the F-35B has double the (empty) weight compared to the from the Harrier II (13,600 kg vs. 6,340kg). This results in considerable jet blast and water spray, as can be seen here. Main requirement for the F-35B is a combat radius of 450 nm on internal fuel and while carrying 2x 1,000 lbs class weapons (such as the GBU-32/B JDAM) in the weapons bay. This is significantly lower than the 590 nm Hi-Lo-Hi combat radius of the (non-stealthy) AV-8Bs carrying a 3,500 lbs weapons load. To put things in perspective: the `maximum combat range' of the F-15E is quoted as 1,853 km (1,000 nm) [2]. In March 2012, the US Air Force agreed to relax the minimum combat range requirement to 583 nm, 17 nm below the initial requirement. The range was reduced after Pratt & Whitney diverted more bleed air from the F135 powerplant for cooling purposes, as the engine was running hotter than expected. The US Air Force also accepted new estimates that reduced the F-35A's fuel capacity and added the weight and drag of the Lockheed electro-optical targeting system. Another key performance parameter is the sortie rate. The B-model is required to generate four sorties per day, the A and C models are only required to generate three sorties per day.

Avionics and systems

The F-35 is fitted with an impressive avionics suite. Primary sensor is the Northrop Grumman AN/APG-81 AESA radar, BAE Systems AN/ASQ-239 EW system (derived from the AN/ALR-94 suite fitted to the F-22), Elbit/Rockwell HMDS, Lockheed Martin AAQ-40 E/O Targeting System (EOTS) and Northrop Grumman AN/AAQ-37 Distributed Aperture System (DAS), providing missile and aircraft detection, tracking and warning. Like the F-22. the F-35 uses sensor fusion, of which the integration of the AN/APG-81 radar and the AN/ASQ-239 EW system is a perfect example. Because the advanced HMDS, the F-35 is not fitted with the usual HUD. New key avionics item is the Harris Corporation Multifunction Advanced Data Link, which provides secure data-linking technology between stealth aircraft such the F-22 and B-2. A major innovation is the Honeywell IPP. The F-35 is one of the first "more-electric aircraft", meaning it uses electricity to replace several functions formerly fuelled by hydraulics or pneumatics. The 200 hp IPP provides engine start power, on-board cooling and emergency power. Harris Corporation delivers the avionics infrastructure for the radar and Integrated Core Processor Electronics (ICP) and fibre-optic network solutions and power supplies.

Development concerns

Development costs

For the F-35A (excluding the F135 engine), the target price was $221.2 Mio (LRIP-1), $161.7 Mio (LRIP-2) and $128.2 Mio (LRIP-3). In July 2011, the US Air Force F-35 programme office confirmed the estimated cost overrun for the LRIP-1 to LRIP-3 aircraft is roughly $1.15 billion. The higher figure includes the roughly one-third share of the overrun absorbed by Lockheed Martin and Pratt & Whitney. The US government has to pay the remaining $771 million in extra costs under the terms of the first three lots of LRIP. Under the terms of the LRIP 4 contract, Lockheed Martin and the Pentagon share any costs above the ($111.6 Mio excluding the engine) target price 50:50, with a ceiling on what the government would have to pay of 120%. So an F-35A could cost the DoD up to $133.9 million (excluding engines). Beyond that Lockheed Martin carries the cost. A single F119 engine is quoted to cost approx. $ 20 Mio, taking the minimum LRIP-4 unit cost price tag to approx. $132 Mio. Therefore, the F-35 is under constant threat to be delayed or even cancelled due to the cost overruns.

Development time

F-35 development time takes longer then expected. These are caused by technical setbacks, as well as funding issues. Several potential F-35 operators are considering to order or upgrade 4th generation fighters in order as a gap-filler measure until the F-35 has reached IOC. The Royal Australian Air Force already ordered 24 F/A-18F Super Hornet aircraft (and considering acquiring additional ones), while the US Navy basically faces the same problem. The US Air Force is considering to upgrade late model F-16C Block 40/50 aircraft while waiting for the arrival of the F-35. Several potential international customers are examining alternatives, driven by the escalating unit price and delayed time schedule. To make things worse, the US Air Force launched a service life extension study for its F-15E fleet, where it widely assumed the US Air Force would replace the F-15E with the F-35A.


Some observers feel that the F-35 is over optimized to prevent detection by fighters and tracking radars in front of it, it lacks the maneuverability and SEP in air-to-air combat [3]. The wing loading of the F-35A is quite high (approx. 20% higher than F-16C, MiG-29M and Su-27/Su-30) making it less agile and requiring a higher thrust to a given turn radius and speed. The thrust loading is significantly inferior to the F-15, F-16, F-22, MiG-29M and Su-27/Su-30, resulting in slower acceleration, slower climb, more energy bleed in tight turns. To make matters worse, early 2013 the US Air Force lowered the performance bar for sustained turn rate and acceleration. The specifications for all three variants pertaining to transonic acceleration and sustained turn rates have been reduced:

  • F-35A

• increased time for acceleration from 0.8 Mach to 1.2 Mach by at eight seconds

• reduced sustained turning performance from 5.3g to 4.6g

  • F-35B

• increased time for acceleration from 0.8 Mach to 1.2 Mach by at 16 seconds

• reduced sustained turning performance from 5g to 4.5g

  • F-35C

• increased time for acceleration from 0.8 Mach to 1.2 Mach by at least 43 seconds

• reduced sustained turn performance from 5.1g to 5.0g

Having a maximum sustained turn performance of less than 5g is the equivalent of an F-4 Phantom II or an F-5[4]. All three variants are having problems with their horizontal tails, experiencing higher than expected temperatures during sustained high‑speed / high‑altitude flight, resulting in delamination and scorching of the surface coatings and structure.

Stealth capabilities

The F-35 has continued the move away from high-maintenance coatings, with a greater use of durable, low-maintenance structural materials. Even so, the F-35 reportedly has a RCS of around 0.00143 m², which is about 7 to 9 times bigger than the minimal frontal RCS of the F-22 Raptor, but 1/35 to 1/70 of the frontal RCS of the western 4th+ Generation fighters such as Typhoon, Dassault Rafale and F/A-18E/F[5]. To put things further in perspective, the F-35 stealthiness is a bit better than the B-2 Spirit bomber, which, in turn, was twice as good as that on the even older F-117 Nighthawk. Unlike the Raptor, the F-35’s stealth is primarily directed at radars in front of it, especially X- and upper S-band systems used by fighters, SAMs, and tracking radars, and, to a lesser extent, L-band surveillance systems [6], making it stealthy for head on detection only . Furthermore, new 'counter stealth radars' are being developed. These new radars operate in low bandradars, especially operating in the VHF band. While the F-35 is frequently criticized for the limitations of its stealth capability in the mid and upper microwave bands, the compact size of this aircraft makes it highly susceptible to detection by these low band (VHF) radars, unlike larger aircraft such as the B-2A Spirit.

Airframe structure

F-35A/B forward root rib

Thirty F-35A and 34 F-35B airframes built early in the aircraft's production run will require modification to achieve their full 8,000-flight-hour design lives. That's because program engineers identified a shortfall with a structural component in their wings, known as the forward root rib. It's an aluminum part located where the leading edge of the wing meets the strike fighter's fuselage. The engineers came across this issue initially during an analytical assessment of the F-35 airframe's fatigue life. The new modified forward root rib design will be incorporated into production planes from the beginning of Low Rate Initial Production (LRIP) Lot 5 for both CTOL and STOVL aircraft. The F-35C is not affected by this issue[7].

F-35B bulkhead 496

In November 2011, after sea trials on-board the USS Wasp, three of the five developmental F-35Bs have developed tiny cracks in a lift fan-related component which prevent the flight-test aircraft from reconfiguring in flight and landing vertically. The potential for cracks to develop in the actuator support beam was revealed several years ago when the Alcoa-supplied 496 bulkhead in the rear fuselage of the F-35B cracked unexpectedly only 10% through the durability test cycle. Subsequently, it was revealed in 2014 that cracks on the F-35B primary support structure were more extensive than previously thought. The initial cracks were found late 2013 on section 496, a primary wing carrythrough bulkhead, prompting officials to stop the ground-based testing at hour 9,400 during the second life’s worth of use — or second 8,000 hr. of equivalent flight hours — to investigate the issue. Since then, cracking also has been discovered on adjacent bulkheads.

F-35B/C Transonic roll-off and buffeting

Meanwhile, the F-35B and C variants continue to have issues with transonic roll-off and buffeting. On the F-35B, the program introduced vehicle systems software to reduce rudder and flaperon hinge moment in the transonic/supersonic region. Moreover, in December 2012 after multiple cracks were found in a F-35B bulkhead flange on the underside of the fuselage during the 7,000-hour inspection.

No alternative engine

While the F110 was developed as alternative engine for the F100, the DoD cancelled funding for the General Electric F136 engine, which would have been the alternative engine for the F135.


As early as August 2007, there have been issues with the IPP. In 2007, an IPP shut down on the integrated test stand. The test stand was damaged as a result of the shut down and had to be refurbished. Stator and rotor clearance issues within the IPP have been identified as the root cause. Honeywell redesigned the IPP and the first redesigned model was delivered October 2007. However, SDD flight operations were suspended on August 2nd 2011 and the US Air Force safety oversight board launched an investigation after conventional take-off and landing flight test aircraft AF-4 experienced an "explosive event" during a routine ground test. A control valve malfunction caused the IPP to fail after starting up the F-35's engine. The IPP is used to start the engine, and then powers the system that cools the F-35's power supply. Flights were resumed August 23rd 2011. Another concern is damage the (carriers') flight deck. In March 2010, the GAO reported that exhaust from the engine and integrated power package exhaust may cause excessive damage to the flight deck environment and runway surfaces that may result in operating limits or drive costly upgrades and repairs of F-35 basing options.


F-35 noise levels that are reportedly up to two times louder than the F-15 fighter, and close to four times louder than an F-16. This issue has forced a delay in critical approvals for Eglin AFB, and has also become an international concern. With respect to perceptions of loudness, every 10 decibels will double apparent volume, so a 10-decibel difference is about 2x as loud, a 19-20db difference is 4x as loud, and a 30db difference would be about 8x as loud.

Cyber security

The US Marine Corps has expressed concerns about the security of the Autonomic Logistics Information System (ALIS). The ALIS system has both a classified and unclassified node in the same system. The unclassified part of the system deals with maintenance information, the classified side of the ALIS system deals with mission planning for the pilots who will fly the aircraft. As a temporary solution, the classified and unclassified systems were separated. As of November 2012, the US Marine Corps does not yet have a definitive date as to when it expects the work to be completed.

Other issues

In November 2011, a study team found the following 13 areas of concern remained to be addressed in the F-35[8]:

  • The helmet mounted display system does not work properly (a new ' Gen3' helmet will start flight tests in 2014).
  • The fuel dump subsystem poses a fire hazard.
  • The Integrated Power Package is unreliable and difficult to service.
  • The F-35C's arresting hook does not work (a redesigned tailhook started flight test December 2013 and the issue now seems to be solved).
  • There are classified "survivability issues", which have been speculated to be about stealth.
  • The wing buffet is worse than previously reported.
  • The airframe is unlikely to last through the required lifespan.
  • The flight test program has yet to explore the most challenging areas.
  • The software development is behind schedule.
  • The aircraft is in danger of going overweight or, for the F-35B, too nose-heavy for VTOL operations.
  • There are multiple thermal management problems. The air conditioner fails to keep the pilot and controls cool enough, the roll posts on the F-35B overheat, and using the afterburner damages the aircraft.
  • The automated logistics system does not work properly.
  • The lightning protection on the F-35 Lightning II is uncertified, with areas of concern.

As of the end of January 2016, the program had 931 open, documented deficiencies, 158 of which were Category 1, defined as deficiencies which may cause death, severe injury, or severe illness; may cause loss of or major damage to a weapon system; critically restricts the combat readiness capabilities of the using organization; or - in other programs - would result in a production line stoppage.


System Development and Demonstration

While the actual JSF development contract was signed on 16 November 1996, the contract for System Development and Demonstration (SDD) was awarded on 26 October 2001 to Lockheed Martin, whose X-35 beat the Boeing X-32. Although both aircraft met or exceeded requirements, the X-35 design was considered to have less risk and more growth potential. The 10-year SDD phase involves the development and testing of the entire aircraft system, including its manufacture. During SDD, the team will build a total of 19 test aircraft. Fourteen will undergo flight-testing, seven will be used for non-airborne test activities, and one will be used to evaluate the F-35’s radar signature. Nine nations are partnering in the F-35’s SDD phase with participation varying in three tiers. Tier 1 countries are the United States and the United Kingdom, the latter contributing 10% of the development costs. Tier 2 countries (Italy, the Netherlands) will contribute around 5% each. Tier 3 participants (Turkey, Canada, Denmark, Norway and Australia) will each contribute between 1% and 2%. Participating countries receive industrial orders and royalties for non-partner sales. Singapore and Israel are “Security Cooperation Partners”.

Initial Operational Test & Evaluation

Tier 1 and 2 countries can participate in the Initial Operational Test & Evaluation (IOT&E) phase. So far, the United States, United Kingdom and the Netherlands signed for the IOT&E phase.

Production Sustainment and Follow-on Development

This phase covers the follow-on development of the F-35 for its entire operational career. Late 2006, all participating countries signed the MoU for the PSFD phase.


The top two industrial partners on the airframe portion of the program are Northrop Grumman (which provides the completes centre fuselage, delivering the 50th centre fuselage 17 August 2011) and BAE Systems (which provides the rear fuselage and horizontal and vertical tail planes). The structure is transported to Lockheed Martin's Fort Worth final assembly. It then is integrated with the other major sections including the Lockheed Martin produced forward fuselage, cockpit and wings, Pratt & Whitney supplied engine and Northrop Grumman supplied radar and sensor suite. The F135-PW-600 engine for the F-35B, equipped with unique Shaft Drived LiftFan® (SDLF) gearbox and 3 Bearing Swivel Nozzle (3BSN), is developed in cooperation with Rolls-Royce. The development of the General Electric F136 alternate engine (like the F110 was for the F100), ended the contract with General Electric, leaving the F-35 program with a sole engine supplier.

Low Rate Initial Production

In order to compensate for the constant cost overruns, the DoD aanounced in 2011 it will reduce significantly the number of airframes to be included in LRIP-5 and beyond. Early 2012, the DoD said it will delay U.S. orders for another 179 jets until after 2017, bringing the total number of US F-135s delayed to over 400.


21 April 2007, the DoD approved the release of full funding for two F-35A aircraft (LRIP-1).


July 2007, LRIP-2 contract for six F-35A and six F-35B aircraft.


15 May 2008, LRIP contract of 7 F-35A and 7 F-35B for the US Marine Corps, 2 F-35B's for the Royal Air Force and a single F-35A for the RNethAF. The LRIP-1 to LRIP-3 contracts were 'cost plus'.


The LRIP-4 included 32 aircraft, including 10 F-35A, 16 F-35B and 4 F-35C for US services, a single F-35A for the Royal Air Force and a second F-35A for the RNethAF. Initially loaded with Block 2A software. LRIP-4 was the first Fixed Price Incentive Firm Target contract for the F-35. Previous batches had been cost-plus.


In November 2012, LRIP-5 for 32 aircraft was contracted. Loaded with Block 2A software. For LRIP-5, Lockheed Martin will build 22 F-35A, three F-35B and seven F-35C aircraft. Originally, LRIP-5 was supposed to include 47 aircraft.


Originally 80 planned, LRIP-6 (contracted September 24th, 2013) eventually includes 36 aircraft (23 F-35A (including three for Italy and two for the Australia), six F-35B, 7 F-35C. Loaded with Block 2B and - later - 3i software.


LRIP-7 was also contracted September 24th, 2013 and includes 35 aircraft (24 -A, 7 -B, 4 -C). Included in the contract are parts for three F-35As for Italy, two F-35As for Turkey and one STOVL jet for the UK. Loaded with Block 2B and - later - 3i softwae. Originally, Lot 7 was expected to contain 77 aircraft. Unit cost of LRIP-7 aircraft is 6% lower than LRIP-5 aircraft and are specified by Lockheed Martin as $98 million for the 24 F-35A, $104 million for the F-35B and $116 million for the F-35C aircraft. All prices are excluding the engine, which is contracted separately with Pratt & Whitney. Engine unit price in Lot 7 was quated as $ 26.2 million, so a baseline Lot 7 F-35A would cost $ 124.2 milion.


November 21, 2014, the DoD and Lockheed Martin have reached for the production of 43 F-35 Lightning II aircraft. The LRIP-8 contract procures 29 US aircraft including 19 F-35As, six F-35Bs and four F-35Cs. It also provides for the production of the first two F-35As for Israel, the first four F-35As for Japan along with two F-35As for Norway and two F-35As for Italy. The United Kingdom will receive four F-35Bs. The LRIP 8 aircraft join 166 F-35s contracted under LRIPs 1-7. As of October 24, 2014, 115 F-35s, including test aircraft. Per-variant price tag of Lot 8 aircraft is as follows: F-35A: $94.8 million, F-35B: $102 million, F-35C: $115.7, all excluding the engine. LRIP-8 brings the total number of contracted F-35s to 216. Engine unit price in Lot 8 was quated as $ 21.9 million, so a baseline Lot 8 F-35A would cost $ 116.7 milion.


LRIP-9 was contracted December 2016 and includes 57 airframes: 42 F-35A model ($ 102.1 million a jet), 13 F-35B model ($ 131.6 million a jet) and 2 F-35C model ($132.2 million a jet). In April 2016, Pratt & Whitney was already awarded a $1.4 billion contract for the production 66 engines (approx $ 21 million a piece).


LRIP-10 was contracted February 2017 and includes 90 aircraft (76 F-35A, 12 F-35B and 2 F-35C models). Customers are US Air Force (44 F-35A), US Marine Corps (9 F-35B), US Navy (2 F-35C), United Kingdom (3 F-35B), Norway (6 F-35A), Australia (8 F-35A), Turkey (2 F-35A), Japan (4 F-35A), Israel (6 F-35A) and South Korea (6 F-35A). Price level (excluding the engine) sit at $ 94.6 million (F-35A), $ 122.8 million (F-35B) and $ 121.8 million (F-35C). In July, Pratt & Whitney was contracted to deliver 99 engines for $ 1.5 billion, adding an avarage $ 15 million a piece to an F-35 airframe.

Full Rate Production


FY2015, 1st Full Rate Production (FRP-1) batch, expected to contain 107 aircraft.



Conventional take-off and landing (CTOL) version under development for United States Air Force and various international customers, powered by F135-PW-100 engine and stressed for 9g manoeuvres. The F-35A uses standard runways for take-offs and landings. Internal fuel capacity is 18,250 lbs, providing an combat radius (internal fuel, 2x 2,000 lbs class bombs, 2x AIM-120) of 590 nm. F-35A carries a 25 mm GAU-22/A cannon internally. The standard internal weapons load is two AIM-120C air-to-air missiles and two 2,000-pound GBU-31/B JDAM guided bombs. Optional internal loads include eight GBU-39 Small Diameter Bombs, as well as a wide variety of air-to-ground missiles, dispensers and guided weapons, including the B61 nuclear weapon and (in Norwegian service) the Kongsberg Joint Strike Missile. The internal weapons bay is reconfigurable for all air-to-ground ordnance, all air-to-air ordnance or a blend of both. When stealth is no longer required to execute a mission, the F-35A external pylons are loaded with ordnance, giving the aircraft a weapons payload of 18,000 pounds. The internal bomb bay has BRU-68/A bomb racks. The customised version for the Isreali Air Force is designated F-35I Adir. Israel will integrate its own electronic warfare systems such as main computer, sensors and countermeasures designed and produced domestically. Additionally, the F-35I will feature an external jamming pod, Python-5 air-to-air missiles and Spice 1000 guided bombs in the internal weapon bays. Norwegian aircraft will provision for a drag chute, packed in a small bump on the upper surface between the two vertical tails.


Short-takeoff/Vertical-Landing (STOVL) version under development for US Marine Corps and Royal Air Force, powered by F135-PW-600 turbofan engine with Rolls-Royce LiftSystem®, consisting of a Liftfan® and 3 Bearing Swivel Module (3BSM) swivelling exhaust. Internally, two 1,000 lbs bombs can be carried (compared to 2x 2,000 lbs in case of the F-35A/C), due to the somewhat smaller bomb bay dimensions. The reasons for this is the complex propulsion system with the large Liftfan® just behind the cockpit. With 13,500 lbs, the internal fuel capacity is also smaller, providing an unrefuelled combat radius of 450 nm (internal fuel and 2x 1,000 lbs class bomb) [9]. The internal bomb bay has BRU-67/A bomb racks. A version of the 25 mm GAU-22/A cannon is pod mounted. The F-35B is stressed for 7.0g manoeuvres. Primary customers were be the US Marine Corps, the Royal Air Force/Royal Navy and the Italian Navy, although the UK announced a switch to the carrier capable (and less expensive) F-35C. First supersonic flight (to Mach 1.07 at 30,000ft (9,150m)) was reached on 10 June 2010.


Carrier based (CV) version under development for United States Navy, powered by F135-PW-400 turbofan engine, stressed for 7.5g and strengthened landing gear (constructed from Aermet 100 steel and with twin nose-wheel gear) to allow carrier operations and (compared to the F-35A) 22% bigger wing to allow lower approach speeds. F-35C internal fuel capacity is nearly 19,750 lbs, providing an combat radius of greater than 640 nm (same conditions as stated in the F-35A section)[10]. With twice the range on internal fuel as the F/A-18C Hornet, the F-35C achieves much the same goal as the F/A-18E/F Super Hornet. The internal bomb bay has BRU-68/A bomb racks. First flight was 8 June 2010.

Software blocks

Block 0

Designation for initial System Development and Demonstration airframes.

Block 0.1

Initial F-35s are flying with Block 0.1 vehicle management system software.

Block 0.5

Interim avionics and software standard, rolled out on January 22nd, 2009 in F-35B c/n BF-4. This software only supports training and test support activities.

Block 1

Development standard with only basic capability, i.e. to support the JDAM and AIM-120 AMRAAM. Block 1 software for the mission system was first flown on the 737-based Cooperative Avionics Test Bed (CATBird) mid 2010. One a/c ordered by the Royal Netherlands Air Force to participate in the Initial Operational Test & Evaluation (IOT&E) phase. Block 1B software was installed mid 2012.

Block 2

Software block fitted to LRIP4 aircraft. Lockheed Martin flew the first test flight with Block 2A software on March 2nd, 2012 and the 1st aircraft was delieverd May 6th 2013. The Block 2A configuration adds new functionality to the F-35. The aircraft was previously only able to operate three of its six Northrop Grumman AN/AAQ-37 electro-optical distributed aperture system DAS infrared cameras. The Block 2A has all six cameras installed and operative. Additionally, the Block 2A is cleared to turn on the Lockheed Martin electro-optical targeting system (already installed in the Block 1B but not cleared to operate). Finally, the initial Block 2A software release adds a weather radar mode. Block 2B software, released for flight test in February 2014 and available to the F-35 fleet mid 2015, is the “initial warfighting” software that adds sensor capabilities missing from the training software releases, plus the provisions fo two AIM-120 AMRAAM air-to-air missiles, and two GBU-12 LGBs or GBU-32 JDAM. This software was uploaded in May 2016 to LRIP-2/3/4/5 aircraft.

Block 3

Block 3i

Block 3i (Interim) is the Block 2B software rehosted on newer avionics hardware. In May 2016, the upgrade of LRIP-6/7/8 aircraft was started. Block 2B development was terminated in May 2015, and the US Marine Corps declared F-35B IOC in July 2015, despite known deficiencies and with, as expected, limited combat capability. Block 3i developmental flight testing restarted for the third time in March 2015, after two earlier attempts in May and September 2014. Block 3i began with re-hosting immature Block 2B software and capabilities into new avionics processors. Though the program originally intended that Block 3i would not introduce new capabilities and would not inherit technical problems from earlier blocks, both of these things occurred. Despite ongoing severe problems with avionics stability, sensor fusion, and other issues, the program terminated Block 3i developmental flight testing in October 2015, and released Block 3i software to the fielded units. This decision was made, despite the unresolved Block 3i deficiencies, in an attempt to meet the unrealistic current official schedule for completing development and flight testing of Block 3F mission systems. The extent to which the significant outstanding deficiencies are being addressed thus far is still to be determined; the program plans to begin flight testing of another version of Block 3i software, version 3iR6.21, in late March 2016.

Block 3F

Block 3F (Final) adds weapons such as the AIM-9X and AGM-154 JSOW, and sensor capabilities such as full radar synthetic aperture radar mapping (SAR), plus expansion of the flight envelope. The goal is to deliver full Block 3F capabilities in the fall of 2017. In February 2016, when the then latest version of Block 3F software – version 3FR5 – was delivered to flight test, it was so unstable that productive flight testing could not be accomplished. Consequently, the program elected to reload a previous version of Block 3F software – version 3FR4 – on the mission systems flight test aircraft, to allow limited testing to proceed.

Block 4

Enhanced version. Upgrades include increased airframe life, improved power/thermal management, Multifunction Advanced Data Link and Link 16 datalink, JSOW Block 3, AIM-9X Sidewinder Block II, B61 and Joint Strike Missile (Norwegian aircraft) integration. Expected to be released by 2019. The FY2014 budget request shows that B61-12 integration is scheduled for Block 4A and Block 4B aircraft in 2015-2021 with full operational capability in 2022 – three years after the first B61-12 is scheduled to be delivered.

Block 5

Block 5 includes new maritime radar modes (ISAR, Infrared Search and Track, EW upgrades and integration of six AIM-120D AMRAAM missiles. Expected to be available for fleet service by 2021.

Block 6

Enhanced version, with range and propulsion improvements, electronic attack functions, Blue Force Tracking, all-aspect passive threat detect/response management.

Block 7

Block 7 will introduced improved protection against biological/chemical warfare threats.

Armament options


Air-to-air armament options include the AIM-120 AMRAAM missiles (mounted on bay mounted LAU-147/A launchers on Stations 5 & 7) and AIM-9X missiles (on LAU-148/A launchers, also capable of launching the AIM-120 AMRAAM).


Legacy PGM can be carried, such as the Paveway series LGBs. Other weapons include the SDBII (up to eight internally, using the new Joint Miniature Munitions Bomb Rack Unit, in a non-stealth configuration using external pylons, a further 16 more can be carried) and JDAM series, Raytheon AGM-154 JSOW and Lockheed Martin AGM-158 JASSM (Joint Air-to-Surface Standoff Missile). The MBDA Spear is being developed for Britsh F-35B's. On US an selected NATO allies, the B61 Mod12 nuclear weapon will be integrated.


Air-to-surface options include the Kongsberg Joint Strike Missile, integrated specifically for Norway.

Nuclear strike

The US Air Force and selected European operators will certify their F-35 for the B61 Mod12 nuclear weapon.


F-35 Program milestones
October 2001 SDD contract awarded
December 2006 First flight F-35A
11 June 2008 First flight F-35B (BF-1)
June 2010 First flight F-35C
4 October 2011 First F-35B vertical landing at sea (LHD-1 USS Wasp)
April 2012 First Klu F-35A rolled-out
3 November 2014 F-35C (CF-03) 1st arrested landing aboard an aircraft carrier (CVN-69 USS Nimitz)
12 March 2015 First Italian produced F-35A (AL-1) rolled-out

Potential Customers

Estimated production run: approx. 3,400

Longer term prospects:


More information

External links

Social media



  1. ^ Lockheed Martin website August 17, 2011
  2. ^ Global Security website, 18 October 2011
  3. ^ Rand Corporation, Project Air Force, Air Combat Past, Present, Future, August 2008
  4. ^ Flightglobal 30 January 2013
  5. ^ f-16.net forum
  6. ^ Tracking the development of anti-stealth countermeasures
  7. ^ Air Force Magazine, September 6, 2011
  8. ^ Department of Defense, F-35 JSF Concurrency Look Review, November 29, 2011
  9. ^ Air International, December 2010
  10. ^ Air International, December 2010
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