In part 2 of a series of F-35 articles for AeroResource, Mark Forest & Jason Grant take a look at the oft troubled development of the Lightning II, the progress to date with bringing the aircraft into service and what plans the future holds.

For Part 1 – CLICK HERE


Current United States’ Department of Defense plans are for 2,457 aircraft across all three variants, for the United States Air Force, Marine Corps and Navy, at a total estimated acquisition cost of approximately $400 billion. As well as operational airframes, this total includes 14 research and development aircraft, with the average procurement unit cost of an F-35 (in Fiscal 2012 dollars) being $89.0 million – but this is without the cost of an engine. Each engine has an average unit cost of $18.8 million (based on Low Rate Initial Production ,Lot 7 values). The DOD estimates the F-35 will cost approximately $1 trillion to operate and support over the aircraft’s lifetime.

The engine costs quoted do not discriminate between the engines used in the three different versions of the F-35, and clearly the cost of the engine and lift fan used in the F-35B is far higher than that of the engine used in both the F-35A and F-35C conventional thrust models. The sole Pratt & Whitney F135 which powers the Lightning II is a derivative of the F119 advanced turbofan engine used in the F-22 Raptor. Learning lessons from the development of the F119, the engine manufacturer claims it has been able to design an engine for use in a single engine aircraft that incorporates advanced prognostic health management systems which are able to detect a problem to significantly lower maintenance costs and reduce the risk to both the engine and the aircraft- although many remain skeptical about using a single engine for a naval combat aircraft.

The US Air Force is procuring 1,763 F-35A conventional take-off and landing (CTOL) aircraft to replace both the Lockheed Martin F-16 Fighting Falcon and the Boeing A-10C Thunderbolt II. The F-35A is intended to be a more affordable complement to the F-22 Raptor, hence being purchased in significantly larger numbers. Whilst the F-35A is not as stealthy or capable in an air supremacy role as the F-22, it is touted to be significantly more capable than the F-16. The F-35 has the dubious honor of being the most panned combat aircraft of recent times, with multiple reports citing various sources who claim less than optimal performance of the aircraft – most recently that the F-35A lost out to the F-16 in air combat manouevres. The accuracy of many statements on the performance of the F-35 probably cannot be verified, and it will not be until the aircraft has worked up to operational capability that a true indication of it’s capability will be obvious, but currently the US Air Force expects that the F-35A / F-22 combination will provide a significant margin of superiority across the spectrum of conflicts in which they will be involved.

The US Marine Corps is procuring 340 F-35B short take-off and vertical landing (STOVL) version to replace the AV-8B Harrier II, and 80 F-35C carrier variant (CV) to replace the F/A-18 A, B, C and D Hornets. The F-35B is better suited to the needs of the Marine Corps (the air component of which primarily exists to support the amphibious ground capability of the organization) and the sophisticated sensor suite and very low observable, fifth generation strike fighter capabilities, particularly in the area of data collection, support the Marine Air Ground Task Force well beyond the abilities of today’s strike and electronic warfare assets – maintaining viability in an increasingly technologically advanced battlespace.

The US Navy is procuring 260 F-35C carrier variant (CV) to operate as part of the carrier air wing alongside the F/A-18E/F Super Hornet, and EA-18G Growler. The F-35C will be the first Navy combat aircraft designed for stealth, after the A-12 Avenger program was cancelled in 1991. The Department of the Navy believes the commonality designed into the F-35 program will minimise acquisition and operating costs of Navy and Marine Corps tactical aircraft, and will allow enhanced interoperability with the US Air Force, and partner nations participating in the development of the F-35. Interoperability is one of the key philosophies – and arguably key selling points – behind the Lightning II.

Manufacturing Base

The F-35 is manufactured in several locations. Lockheed Martin builds the aircraft’s forward section in Fort Worth, Texas. Northrop Grumman builds the mid-section in Palmdale, California while the tail is built by BAE Systems, here in the UK.

In July 2010, Lockheed Martin and Alenia Aeronautica agreed to establish an F-35 final assembly and checkout facility at Cameri Airbase in Italy to deliver aircraft for Italy and the Netherlands. The facility opened in July 2013, and aircraft AL-1 made the historic first flight of the type outside of the USA when it performed an initial test flight on September 7th 2015.

Lockheed Martin F-35 test pilot Bill “Gigs” Gigliotti, lifted off the runway at 1:05 p.m. European Standard Time for a 1:22 hour check flight in AL-1 marking a historic milestone for Italy, Finmeccanica-Alenia Aermacchi manufacturing cooperation and Lockheed Martin (NYSE: LMT).

Lorraine Martin, Lockheed Martin F-35 Program General Manager said of the first flight:

The first flight of AL-1 is a monumental achievement thanks to the hard work and dedication of our Finmeccanica-Alenia Aermacchi and Lockheed Martin teammates. Italy’s ‘primo volo’ (first flight) sets a firm foundation for Italy’s F-35 program and future opportunities for the Cameri FACO. My heartfelt congratulations to all who worked tirelessly to bring us to this major international program milestone.

The first flight for AL-1 went as planned, said Bill Gigliotti:

As expected, the jet performed exceptionally well and without any surprises. I’m honored to have flown AL-1 on its maiden flight and grateful to the Cameri team for providing a great jet. We look forward to continued successes leading up to aircraft delivery later this year.

The Cameri FACO is owned by the Italian government and operated by Finmeccanica-Alenia Aermacchi in association with Lockheed Martin. The Cameri FACO’s F-35 production operations began in July 2013 and ‘rolled out’ Italy’s first F-35A aircraft, AL-1, in March. AL-1’s official delivery to Italy is expected by the end of the year. The facility will assemble both Italy’s F-35A conventional takeoff and landing variant and the F-35B short takeoff/vertical landing variant, and is planned to assemble the Royal Netherlands Air Force’s F-35A aircraft in the future. The F-35A and F-35B will replace Italian Air Force and Italian Navy AV-8 Harriers, Panavia Tornados and AMX fighters.

In addition to its responsibility in the operations of the FACO, Finmeccanica-Alenia Aermacchi also produces the F-35A’s full wing-sets. The work contracted to Finmeccanica-Alenia Aermacchi, a strategic co-supplier of F-35A full wing assemblies, is one of the largest manufacturing projects for the Italian F-35 program, with 835 full wing assemblies planned. Finmeccanica participates in the F-35 program also with Selex ES, responsible for various onboard electronics.

In the United Kingdom, BAe Systems are a principal industrial partner to Lockheed Martin and were able to offer a history of capabilities to the F-35 program. The UK is playing a vital role in the F-35 (being a Tier 1 Partner), producing the aft fuselage, fuel system, crew escape and life support systems (through Martin Baker). BAe Systems will continue to support follow-on developments and sustainment to the F-35 program over the next 40 years, and will be heavily involved in the UK F-35 program when the aircraft begin arriving in 2018.

International Orders

Commitments from program partners and other countries have changed over time, these are the latest developments (June 2015):

Operator F-35A CTOL F-35B STOVL F-35C CSV
Australia 72 / /
Canada 65 (to be confirmed) / /
Denmark 30 (to be confirmed) / /
Israel 33 + 17 options / /
Italy 60 30 /
Japan 42 / /
Netherlands 37 / /
Norway 52 / /
Singapore No Order Announced / /
South Korea 40 + 20 options / /
Turkey 100 / /
United Kingdom / 138 /
United States 1,763 340 340


The United Kingdom, the only Tier 1 Partner, originally planned to purchase 138 F-35B aircraft, the largest order of any partner country. As part of the Strategic Defence and Security Review 2010, the Ministry of Defence made a controversial decision to purchase the F-35C CTOL instead of the original F-35B STOVL. Following a visit to the USA by Defence Minister Philip Hammond, it was later agreed that the UK would revert back to the original F-35B – at great expense and embarrassment to the then Coalition Government. The reason for the change was cited as the earlier availability of the F-35B and the rising costs associated with equipping the two new Queen Elizabeth Class aircraft carriers for operations using untested Electromagnetic catapults and arresting gear. The bulk of the UK F-35 order is expected to be approved in 2017 with final numbers still to be confirmed and probably subject to the requirements of the forthcoming 2015 SDSR.


To date, more than 5,000 sorties and nearly 10,000 hours of flight testing have taken place using eighteen vehicles (thirteen flyable aircraft and five static test airframes) for the Systems Development and Demonstration (SDD) phase of the F-35 program. The flyable aircraft are split into two categories: flight sciences, and mission systems. The flight sciences aircraft expand the flight envelope and evaluate flying qualities, stability and control, high angle of attack, environmental systems, propulsion, aeroelastics and flutter, loads, dynamic response and store separation. Nine aircraft are used spanning all three variants: four F-35As, three F-35Bs and two F-35Cs. Mission systems aircraft are used to test aircraft interoperability, stores integration, avionics integration and communications (data links and satellite), as well as the AN/AAQ-37 Electro-Optical Distributed Aperture (EODAS) situational awareness and targeting system. The four aircraft that are used are again divided between all three variants, with one F-35A, two F-35Bs and one 35C. The static aircraft are used for structural and fatigue testing as well as to test software updates before being uploaded to the SDD flight tests aircraft.

The first test flight of the F-35 Lightning II took place on 15th December 2006 when F-35A AA-1 took to the sky. With Chief Test Pilot Jon Beesley at the controls, the jet climbed straight up to 15,000 feet at a maximum speed of 225 knots. The speed was limited due to the gear remaining, as planned, in the lowered position. At 15,000 feet, a series of manoeuvres were executed to evaluate the handling qualities of the jet. Chief Test Pilot Jon Beesley remained at the controls for the first eleven test flights, with every test expanding the flight envelope.
Test flight 2: The landing gear was cycled up and down and the aircraft flew in formation with the gear up.
Test flight 3: The first military power take-off.
Test flight 4: Low altitude manoeuvring.
Test flight 5: The first transition to engine reheat
Test flight 6: First fuel dump test as well as performing higher angle of attack manoeuvres.
Test flight 7: Speed brake evaluation. The F-35 decelerates using the leading-edge slats, trailing-edge flaps and rudder. Deceleration rates were reported as similar to that experienced in the F-16 when using the speed brake.
Test flight 8: A software patch was tested allowing the full use of lateral stick rolling manoeuvres.
Test flight 9: The first full afterburner take-off, the flight was also the longest flight to date at 1.5 hours. The flight consisted of close formation flying, power approaches and manoeuvres that took the jet to 16 degrees angle of attack at 20,000 feet.
Test flight 10: The mission included full-stick 360 degree rolls, snap engine transients in afterburner and close formation flying. The Helmet Mounted Display (HMD) was used for the first time.

First Flights

First Flight 15th December 2006 First Flight 11th June 2008 First Flight 6th June 2010


The software code is the most complex part of the aircraft. The software controls every aspect of the aircraft from flight controls, radar, navigation and communication to sensors, target identification and weapons. The software allows the F-35 to prioritise threats in contested air space as well as giving the F-35 the ability to communicate with other assets in theatre. One of the biggest challenges during testing has been writing, validating and debugging the software.

The software has been developed in six blocks:

Block 1 (A&B) comprises 78 percent of the more than 8.3 million source lines of code required for the F-35s full war fighting capability. Block 2 (A&B) is currently in operation with the F-35 fleet. Block 2A provides enhanced training including functionality for off-board fusion, initial data links, electronic attack and mission debrief.  Block 2B provides initial war fighting capabilities, including but not limited to expanded data links, multi-ship fusion and initial live weapons. The U.S. Marines have declared IOC with Block 2B.

Block 3i provides the same tactical capabilities as Block 2B. The main difference between 2B and 3i is the implementation of new hardware, specifically the updated Integrated Core Processor. The Air Force will declare IOC with Block 3i. Block 3F provides 100 percent of the software required for full war fighting capability, including data link imagery, full weapons and embedded training.

The aircraft software also includes the Automatic Logistics Information System (ALIS). ALIS monitors the aircraft and provides information to the pilot or ground personnel of any issues with the plane. Along with the other aircraft software, this system is also behind schedule.

Offensive and Defensive Systems

Northrop Grumman Electronic Systems has designed the AN/APG-81 active electronically scanned array radar for the F-35. The advanced fire control radar has been designed to allow pilots to engage both air and ground targets at long range while providing enhanced situational awareness to enhance survivability. Northrop Grumman is also supplying the AN/AAS-37 electro optical distributed aperture system to provide a protective sphere around the aircraft for missile warning, navigation support and night operations.

The AN/AAQ-40 Electro-Optical Targeting System (ETOS) developed and supplied by Lockheed Martin provides the F-35 with long-range target recognition, identification and tracking capabilities. The system is the first to combine both forward-looking infrared (FLIR) and infrared search and track (IRST) capabilities. ETOS improves situational awareness, enabling the pilot to view high-resolution imagery while automatically searching out and tracking multiple targets. Laser designation and tracking allows for precision air-to-air and air-to-surface targeting.

The AN/ASQ-239 Barracuda is an integrated defensive avionics suite designed by BAE Systems. The system can precisely geo-locate the direction of a threat and provide targeting information to counter the threat. BAE Systems is also developing the infrared and radio frequency countermeasures’ systems for the F-35.


The F-35A and F-35C are designed to carry 3,500lbs of ordinance in “low observable” mode within the twin internal weapons bays, and more than 18,000lbs in full external fit when flying in uncontested air space. The F-35A is the only variant to feature an internal cannon, as neither the F-35B or C variants can accommodate the external space, and instead carry the GAU-22 cannon in an underslung pod. The F-35A first fired the internal gun in 2015, with weapons trials from aircraft AF-02 at Edwards Air Force base.
From a launchable weapons perspective, the road has been equally long – starting on the 4th May 2010 when the F-35B flew for the first time with weapons in its internal weapon bay. The aircraft carried an AIM-120 medium range air-to-air missile and a GBU-12 Paveway II laser guided bomb. Fast forward 5 years to 2015, and VMFA-121,  with six F-35Bs, deployed live weapons in Restricted Area 2507 as one of the last steps towards the US Marine Corps declaring Initial Operational Capability.

The F-35B will be able to carry 15,000lbs of weapons using both internal and external hard-points. It has come to light that the F-35B is unable to fit the full internal compliment of eight precision attack small diameter bombs in the internal weapons’ bay, mainly because the F-35B has a smaller weapon bay than both the F-35A and F-35C because of its vertical lift fan directly behind the cockpit. A hydraulic line and structural bracket are being redesigned and modified and will be incorporated into the planned Block 4 release in fiscal year 2022, which should then allow all variants of the F-35 to carry 24 small diameter bombs, 8 internally and 16 externally.

All variants of the F-35 will be able to carry a wide range of ordnance including the GAU-22 25mm pod mounted Gatling gun (F-35B & F-35C), AIM-9X Sidewinder, AIM-120 AMRAAM, AGM-154 JSOW, AGM-158 JASSM, Joint air-to-ground missile, General-purpose bombs, GBU-10/12/16 Paveway II LGBs and GBU-24 Paveway III LGB, GBU-39 small diameter bombs and GBU-31/32/38 JDAMs. In general, the weaponry carried by the Lightning II is the same as with other legacy airframes – but the delivery mechanism is intended to be much more efficient, intelligent and reactive.


The F-35 has suffered no end of many well-publicised problems during testing. Arguably these problems are exactly those that testing is designed to find and fix before any aircraft enters service. With such a state of the art aircraft that is pushing the limits of design and software, technical challenges are always going to be encountered. Some of the higher profile challenges have been:

Cracks in the bulkhead of the F-35B fatigue testing airframe at less than one tenth of the test lifetime, leading to a redesign of the bulkhead for the F-35B.

Premature wear on hinges for the auxiliary inlet door for the lift fan caused the F-35B fleet to be grounded between September 2010 and January 2011, after issues were discovered on the BF-01 test vehicle.

Higher than expected heat levels for the F-35B roll-post nozzles led to a redesign; this was due to the expansion and contraction of the driveshaft, exceeding design limits during flight operations – and only effected the Pratt and Whitney designed part during STOVL operations.

The $400,000 per unit, helmet has suffered problems during early development. The state-of-the-art Helmet Mounted Display System has suffered from early development problems. In early testing, pilots complained of motion sickness when the aircraft encountered turbulence due to a jittery video display. During night missions, a green glow obscured the pilot’s vision. The Pentagon became so concerned with these issues with the Rockwell Collins helmet that BAe Systems was contracted to build a “backup” option. Perhaps in part due to the pressure of competition, the issues have now been overcome and the Rockwell Collins helmet will be provided with every jet ordered.

The Royal International Air Tattoo and Farnborough Trade and Air Show in July 2014 should have seen the F-35 make both its European and international debut, but a catastrophic engine fire on a 58th Fighter Squadron F-35A at Eglin Air Force Base on June 23rd grounded the entire fleet; a public relations’ nightmare for Lockheed Martin.  The engine fire was caused by micro-cracks in the third stage of the integrally bladed rotor, which were eventually traced back to a 2 second manoeuvre, three weeks earlier, causing a “hard rub” on the titanium blade against the engine casing lining. The blade eventually broke and punctured the fuel tank. As a result of the failure, Pratt and Whitney had to redesign the front section of the engines and pick up the costs of the retrofit to the 156 engines already delivered. Until the engines were deemed safe for normal flight, the aircraft had to operate under a severely restricted flight envelope. Approximately 45 days of testing were lost during the grounding, but more significantly the high profile grounding brought the F-35 under scrutiny from the US Congress, who were trying to make savings in the military budget – as well as scrutiny from partner nations who were committed to the program, but also under budget restraints. The F-35 was to many starting to look like a project that was over budget, behind schedule and failing to deliver.

Initial Operating Capability

Initial Operational Capability has been one of the long-distant goal posts for the F-35, and – whilst the definition varies for each service – broadly describes the point at which each service have a single squadron equipped, trained and capable of completing basic assigned combat missions. As with many other timelines on the F-35 program, the original IOC milestones have been delayed.

The F-35A was originally scheduled to achieve IOC in March 2013, but currently is planned between August 2016 (Objective) and December 2016 (Threshold).

F-35A IOC will be declared when the first operational squadron is equipped with between 12 and 24 aircraft, and Airmen are trained, manned and equipped to conduct basic Close Air Support, Interdiction, and limited Suppression and Destruction of Enemy Air Defence operations in a contested environment.

The F-35B was originally scheduled to achieve IOC in March 2012, and was defined as the first operational squadron being equipped with between 10 and 16 aircraft, and U.S. Marines are trained, manned and equipped to conduct Close Air Support, Offensive and Defensive counter Air, Air Interdiction, Assault Support Escort, and Armed Reconnaissance in concert with Marine Air Ground Task Force resources and capabilities. The revised milestone of IOC for the F-35B was between July 2015 (Objective) and December 2015 (Threshold). The U.S. Marine Corps declared IOC with the F-35B Lightning II on 31st July 2015, quite possibly the most important milestone to date for the entire F-35 programme. Marine Fighter Attack Squadron 121 (VMFA-121) based in Yuma, Arizona became the first squadron with the F-35B following a five-day Operational Readiness Inspection, which concluded on 17th July 2015.

Earlier this year, AeroResource were able to spend some time talking to Major Gregory Summa, Executive Officer with VMFA-121. Major Summa talked about his experiences flying the F-35B and how the squadron worked towards IOC.

VMFA-121 received their first aircraft in November 2012 and with Marine Corps Maintainers from the 3rd Marine Air Wing, they were able to expedite the standing-up of the squadron. MCAS Yuma has four F-35 simulators to aid pilot training as well being used to evaluate tactics in a controlled environment.
One of the concerns with all the data available was task saturating the pilot. The F-35 presents the information on a situational tactical display that the pilot can filter. Learning how to set up the filters and optimize the sensors depending on the type of mission is something that the pilots have been able to take forward with the help of Marine Aviation Weapons and Tactics Squadron One (MAWTS-1) who are also based at MCAS Yuma.

MAWTS-1 has two instructor pilots flying with VMFA-121 to help in the development of tactics and evaluation on the F-35B. The two pilots from MAWTS-1 are best placed to interpret operational data from the sensors; other pilots from the squadron can also approach them with observations made during a flight. With a direct line to Industry as well as development test aircraft, an update is usually software based which can be configured when the portable memory device is uploaded to the aircraft. These innovative learning processes improve the efficiency and effectiveness of the F-35 across all services.

During our time with Major Summa, it was obvious to see how passionate he and the U.S. Marines are with the F-35B. A new aircraft that presented many new challenges for the U.S. Marines Corps, something they have always relished. As we concluded our time with the Major, we asked if the U.S. Marine Corps would be ready for I.O.C. this year, his reply “without a doubt”.

The F-35C was originally scheduled to achieve IOC in March 2015. F-35C IOC will be declared when the first operational squadron is equipped with 10 aircraft, and Navy personnel are trained, manned and equipped to conduct assigned missions. The revised milestone of IOC for the F-35C is between August 2018 (Objective) and February 2019 (Threshold).

The F-35B and the United Kingdom

The first F-35B Lightning II, BF-1, rolled off the production line on the 18th December 2007 with the first flight taking place six months later on the 11th June 2008. It was not until 7th January 2010 that inflight STOVL operations began with BAe lead STOVL test pilot Graham T. Tomlinson at the controls. The aircraft climbed to 5,000 feet and at 210 knots the aircraft’s shaft-driven lift fan propulsion system was engaged for the first time. The aircraft was slowed to 180 knots before accelerating and converting to conventional flight; the STOVL test lasted fourteen minutes. Two months later on the 17th March 2010, Tomlinson carried out the first hover and short take-off using BF-1 at Naval Air Station Patuxent River; the next day he completed the first vertical landing on to a 96 foot by 96 foot square pad.

On the 26th January 2010, Squadron Leader Steve Long of the Royal Air Force became the first active duty service pilot from the UK to fly the F-35. With over 2,200 hours of flight time, including more than 100 sorties over Kosovo and Bosnia, Sierra Leone and Iraq, Squadron Leader Long had been based with VX-23 at Naval Air Station Patuxent River since 2008, flying F/A-18 Hornets as part of the pilot exchange program with the US Marine Corps.

On the 19th July 2012 the UK accepted the first F-35 Lightning II in a ceremony at Lockheed Martins’ Forth Worth Plant. Bob Stevens, Lockheed Martin chairman and CEO said, “ It’s fitting that our first delivery to an international partner is to the United Kingdom, because without sustained British innovation over many generations, we would not have an event to celebrate today”.
On the 9th February 2015, 17 (R) Squadron began operational testing the UK’s first F-35B at Edwards AFB in California. The squadron, which is made up of engineers and pilots from both the RAF and Royal Navy, is operating independently from the US base, which is a key milestone in the development of the UK’s Joint Strike Fighter Capability. Three UK aircraft will be used by 17 (R) Squadron at Edwards AFB: BK-1, BK-2 and BK-4. BK-3 has transferred from Eglin AFB to MCAS Beaufort and is currently operating as part of Marine Fighter Attack Training Squadron 501 (VMFAT-501) where it is being used to help train future UK pilots and maintainers.

We leave the final words to the Chief of the Air Staff, Air Chief Marshal Sir Andrew Pulford in a speech made during the stand up ceremony for 17 (R) Squadron at Edwards AFB:

Today is an important day for both the Royal Air Force and the Royal Navy. The start of UK operational testing on the Lightning II aircraft is a significant milestone for us; although our relationship with the United States as partners on the Joint Strike Fighter programme remains as strong as ever. Our collaboration with the US Armed Forces on the world’s largest and most advanced defence project is a clear demonstration of our enduring close military partnership with the United States.

During part 3, we concentrate on the F-35’s integration into the Royal Air Force and Royal Navy and explain how the F-35 will shape the future of the UK armed forces.

AeroResource would like to thank the following people for their help with arranging access and interviews making this article possible; Laurie Quincy, F-35 International Communications Manager Lockheed Martin Fort Worth, John Haire, Public Affairs Director Edwards AFB, Captain Melanie Salinas, Public Affairs Office Marine Air Wing 3 and Major Gregory Summa, Executive Officer VMFA-121.