F-35 Joint Strike Fighter (2024)

Manufacturing

The F-35 team developed and prototyped state of the art manufacturing concepts, tooling, and techniques as part of the JSF Concept Development Program. Lockheed Martin completed a comprehensive Airframe Affordability Demonstration (AAD), which demonstrated innovative fabrication, assembly, and tooling techniques for use on JSF. In addition, Northrop-Grumman and BAE SYSTEMS demonstrated advances in composite technologies and flexible tooling which greatly reduce the cost and time for manufacturing.

The JSF team is employing advanced assembly methods and highly accurate manufacturing machines to help the F-35 achieve its goals of affordability, quality and assembly speed. New milling machines accurate to less than the width of a human hair [hair from a human head is normally between 0.04 and 0.25 millimeters, averaging normally 0.1 millimeters], ensure that the F-35's outer shape is exact and meets its low-observability (stealth) requirements. Assembly time for an F-35 was initially planned to be less than half that of current-generation fighters. The F-35 JSF production line is the state-of-the-art model for high-quality, affordable combat aircraft in the 21st century.

In 2003, Lockheed Martin and the JSF Program Office reached an agreement with the Deputy Secretary of the Air Force for Acquisition to allow Lockheed Martin and Northrop Grumman F-35 assembly plants in Fort Worth, Texas, and Palmdale, Calif., to operate as unclassified facilities. The team reached additional agreements to downgrade the classification of some F-35 parts and materials, to produce a significant reduction in factory operation and supplier costs.

The F-35 JSF assembly line built on the capability demonstrated with the F-16 and other "'lean-manufacturing" aircraft. Advanced production processes, including integration of the digital, paperless factory, were being implemented into F-35 production plans. Lean manufacturing principles, incorporation of shortened flow spans, use of a single, flexible production line for all three variants, use of best-value sourcing within a commercial framework - all these steps yield measurable results in the production phase.

The F-35 assembly line is notable for its automation, reduced tooling, and virtual elimination of hammered rivets. The subassemblies are loaded into simplified tooling capable of building any of the F-35 variants. The machine does its work, and the entire assembly- tool and all - then move to the next position. Previous manufacturing technologies would require different tooling for each variant as well as require the subassembly to be unbolted from one tool and reinstalled in another before the next process could proceed - a time-consuming exercise. Because the three variants have more than 80 percent of their parts in common, all of which are located in the assembly tooling in a common manner, major components such as bulkheads can be manufactured from the same blanks, milled and drilled on the same fixture, and assembled using common tools. Again, using the bulkheads as an example, the only difference among the variants is their thickness.

In Fort Worth, an array of advanced and extraordinarily precise manufacturing machines was finished for the production of the F-35 forward fuselage and wing. Some of the equipment is the largest that has ever been built. The huge Flexible Overhead Gantry, for example, will mill the inside surface of the F-35's composite skin to ensure that the aircraft's outer form is exact - a critical step in assuring stealth performance. Accurate to 50 microns (one micron equals one-millionth of a meter) and working in both horizontal and vertical motions, the machine is unprecedented in its size and purpose.

The main task is to build the aircraft affordably. the F-35 JSF Airframe System Engineering Integration Team wanted to eliminate as much tooling as possible, improve production flow, and reduce disruption and delays. By using precise fabrication and robust assembly methods, it is possbile to eliminate hand fitting and rework as the assemblies come together. The contractors are not using technology for technology's sake; but rather are using technology to reduce cost.

Although the automotive industry was not a direct source of expertise for the F-35, it was a source of inspiration to the people who build the aircraft. Automotive plants don't keep inventory on an auto assembly line. They only have about two hours worth of inventory on the floor at any given time. Even the seats come off the delivery truck in sequence of installation. The F-35 assembly line resembles that line. It is called mixed-model production. Lockheed won't have three assembly lines, it had one line, which might build a CTOL version today, a STOVL version tomorrow.

Comparing the F-35 to current-generation fighters, engineers projected that Lockheed Martin F-35 assembly will reduce tooling by 90 percent, reduce manufacturing time by 66 percent, reduce manufacturing costs by more than 50 percent, require up to 50 percent fewer parts, and require up to 50 percent fewer fasteners.

Leveraging decades of experience in advanced tactical fighters, long-range strike aircraft and systems integration, Northrop Grumman's work on the F-35 program reflects the engineering excellence and systems know-how that built the company. Northrop Grumman is responsible for more than 25 percent of the F-35 aircraft. Its contributions range from integrating the center fuselage to producing key subsystems such as communications and avionics, and developing software for mission planning.

The company's approach to improving manufacturing efficiency reflects five elements: people, process, tools, technology and infrastructure. Each has an important role to play. The skills required of Northrop Grumman's manufacturing workers changed to meet the new requirements. More broadly, adoption of lean principles throughout the enterprise required employees to develop what are called "soft tools" - the skills to understand their process and question the value of each step. Because of these changes, manufacturing workers today are more highly trained than ever before and more familiar with automation and computer technology.

Northrop Grumman instituted lean processes, advanced producibility analysis and ergonomic simulations to support the F-35's rigorous production schedule. The results of using lean tools direct the engineering team towards the most desirable solution and factory layout. lean techniques will also be applied to procurement processes to ensure just-in-time flow of parts and raw materials.

Military aircraft specifications require tight tolerances in the manufacturing process, and automation/robotics help in repetitive tasks that require precision such as drilling holes or applying paints and coatings. Automation is especially important in F-35 assembly.

Northrop Grumman is using several state-of-the-art tools to insure the program stays on course. Precision milling machines trim moldlines, side surfaces and radii; counter bores; and drills holes in composite parts, all at feed rates of up to 600 inches per minute. The 24,000-RPM precision cutter is more than capable of holding all engineering tolerances required for F-35 program parts. A fiber placement machine utilizes new programming technology to wrap tooling mandrels with layer upon layer of carefully directed fiber tape plies. The paint cell employs state-of-the-art robotic technology to apply coating to the insides of the contoured engine air inlet ducts.

In laying out the factory, Northrop Grumman adapted vehicle movement techniques from the automotive industry. Lean principles and a high degree of automation have been incorporated to support the rigorous processes required for the F-35 to remain on schedule. Automated drilling stations produce high quality precision holes. New techniques available through today's computer systems allow the company to analyze and predict the possible outcomes for countless scenarios. Software tools such as advanced computer aided design packages, product data management, production and process simulations, and virtual enterprise environments all contribute to realizing these objectives.

Working as an integrated team with customers, teammates, and suppliers, Northrop Grumman will deliver products that perform as it supports Lockheed Martin's continuous moving line concept and the ultimate one-a-day delivery to the military customer. Product designers, system engineers, manufacturing engineers and quality engineers work in closely coordinated integrated products teams (IPT) to define the requirements needed to quickly match the F-35's cutting-edge design with production process capabilities and supplier capabilities. Real-time interaction with suppliers, as well as open communication channels among partners, maximize the use of best processes across the team.

But as of early 2005 it appeared that the JSF program would lack critical production knowledge when it planned to enter low-rate initial production in 2007. Between 2007 and 2013, when the program was scheduled to move to full-rate production, it expected to buy nearly 500 JSF aircraft - 20 percent of its planned total buys - at a cost of roughly $50 billion. Under the program's preliminary plan, it expected to increase low-rate production from 5 aircraft a year to 143 aircraft a year, significantly increasing the financial investment after production begins.

Between 2007 and 2009, the program planned to increase low-rate production spending from about $100 million a month to over $500 million a month, and before development had ended and an integrated aircraft had undergone operational evaluations, DOD expected to spend nearly $1 billion a month. To achieve its production rate, the program invested significantly in tooling, facilities, and personnel. According to contractor officials, an additional $1.2 billion in tooling alone would be needed to ramp up the production rate to 143 aircraft a year. Over half of this increase would be needed by 2009-more than 2 years before operational flight testing begins.

In its fiscal year 2006 budget submission, DOD reduced the planned procurement quantities for the US. by 38 aircraft through fiscal year 2011. The preliminary figures also included planned quantities for the United Kingdom of 2 aircraft in fiscal year 2009, 4 aircraft in fiscal year 2010, 9 aircraft in fiscal year 2011, 9 aircraft in fiscal year 2012, and 10 aircraft in fiscal year 2013.

In March 2012, DOD completed an extensive restructuring of the F-35 program by increasing the program’s cost estimates, extending its testing and delivery schedules, and deferring near-term aircraft procurement quantities into the future. The restructuring actions should lead to more achievable and predictable outcomes, albeit at higher costs and with longer time frames than originally planned for testing and delivering capabilities to the warfighter.

On 30 September 2013, the Department of Defense Inspector General released a report entitled "Quality Assurance Assessment of the F-35 Lightning II Program." The report concluded that the F-35 Program did not sufficiently implement or flow down technical and quality management system requirements to prevent the fielding of nonconforming hardware and software. This oversight was said to have the potential to adversely affect aircraft performance, reliability, maintainability, and ultimately program cost.

Lockheed Martin Aeronautics Company (Lockheed Martin) and its subcontractors did not follow disciplined AS9100 Quality Management System practices, as evidenced by 363 findings, which contained 719 issues. According to the DODIG, the Joint Program Office did not: Ensure that Lockheed Martin and its subcontractors were applying rigor to design, manufacturing, and quality assurance processes; flow down critical safety item requirements; ensure that Lockheed Martin flowed down quality assurance and technical requirements to subcontractors; establish an effective quality assurance organization; or ensure that the Defense Contract Management Agency performed adequate quality assurance oversight.

In addition, the Defense Contract Management Agency did not sufficiently perform Government quality assurance oversight of F-35 contractors. The DODIG report came as the US Navy's Strike Fighter Squadron One Zero One (VFA-101) hosted a rollout ceremony for the F-35C, the Navy's variant for carrier operations, at Eglin Air Force Base, Florida on 1 October 2013.

It was the opinion of the DODIG in its September 2013 assessment that the F-35 Joint Program Office should ensure compliance with AS9100 throughout the F-35 supply chain; ensure that Lockheed Martin approved all design and material review board changes and variances with Government concurrence; perform process proofing of all critical processes to include first article inspections; modify its contracts to include a quality escape (defined as a nonconforming material that had entered the product, supply chain, or proceeded beyond the acceptance process) clause to ensure the Government did not pay for nonconforming product; assess the impacts and risks to all delivered aircraft for all findings; implement an aviation critical safety item program that met the requirements of Public Law and DoD policy, which would include flow down of requirements for a critical safety item program to Lockheed Martin and its subcontractors; assess the impacts and risks to all delivered aircraft for critical safety item deficiencies; perform technical and quality assurance requirement flow down and verification throughout the F-35 supply chain; establish an independent quality assurance organization, which had the authority and resources to enforce the AS9100 standard and F-35 product quality; revise the Defense Contract Management Agency memorandum of agreement to include explicit quality assurance oversight requirements; and ensure that Defense Contract Management Agency was performing quality assurance oversight commensurate with product criticality. DODIG recommended that the Defense Contract Management Agency in turn provide a comprehensive quality assurance oversight plan for Joint Program Office approval to be included in the memorandum of agreement and audit the execution of the quality assurance oversight plan throughout the F-35 supply chain.

On 23 August 2013, the Joint Program Office and the Defense Contract Management Agency responded to the DODIG findings and recommendations in the report. The Joint Program Office agreed with 8 recommendations, partially agreed with 2, and disagreed with one. The Defense Contract Management Agency agreed with one recommendation and partially agreed with the second. The Joint Program Office stated that it did not have the resources to perform process proofing of all critical processes nor had the responsibility or resources to perform requirement flow down verification throughout the F-35 supply chain. However, DODIG disagreed because it was the Joint Program Office’s responsibility to ensure contractual compliance to prevent nonconformances.

It was also the responsibility of the Joint Program Office to update the contract if the requirements were deficient. In addition, the DODIG included along with the report a Notice of Concern it had sent to the JSF Program Executive Office in April 2012, which said that on average, at final assembly each aircraft had 200+ corrective actions requiring rework or repair. The letter added that the quality management system at LMA's Fort Worth, Texas Plant and the integrity of the F-35 product were jeopardized by a lack of attention to detail, inadequate process discipline, and a “we will catch it later” culture.