Plant tour: Airbus, Illescas, Spain

In 2012, CW senior technical editor emeritus Sara Black wrote about the aviation industry in Spain through her site visits to Airbus’ composites facility in Illescas, next-door Tier 1 Aernnova and nearby research organization FIDAMC. In early 2024, CW had the chance to revisit these facilities to see how they — and the industry — have grown in the years since. This report covers this recent tour of Airbus Illescas; see CW senior technical editor Ginger Gardiner’s report on Aernnova’s Toledo and Illescas sites.

CW’s tour of Airbus’ Illescas facility was led by Mónica Álvarez, head of operations at the Illescas site, and Tamara Blanco, Airbus expert in multifunctional composites. It began with a high-level update on Airbus’ composite operations and goals in Spain, as well as specifically in Illescas.

Across its Commercial, Defense and Space, and Airbus Helicopters divisions, Airbus operates seven manufacturing sites in Spain — San Pablo, Tablada, Cadiz, Illescas, Albacete, Tres Cantos and Getafe — employing more than 14,100 employees.

The 170,848-square-meter Illescas facility, located in the province of Toledo but only a short drive south of Madrid, focuses on composites manufacturing of components for the company’s Commercial division. As Black previously reported in 2012, the facility was built in 1989, and originally manufactured the carbon fiber composite upper and lower wing covers for the Eurofighter, and the upper and lower horizontal tail plane (HTP) skins for the A330, followed by HTP skins for the A320.

In 1991, the plant expanded, building a new space to manufacture the composite Section 19 fuselage sections and skins for lateral boxes for the A380, a plane which was phased out in 2021. When the A350 widebody aircraft — which boasts 50% of its primary structures manufactured from composites, the most of any Airbus commercial aircraft so far — began production in 2015, the plant began manufacturing its lower wing covers and Section 19 fuselages, “and these are our main workload drivers now,” Álvarez says.

The plant’s manufacturing technologies include automatic tape laying (ATL), automatic fiber placement (AFP), autoclave cure, trimming and automatic inspection. All composite parts manufactured at this facility are made from carbon fiber/epoxy prepreg, mostly supplied by Hexcel (Stamford, Conn., U.S.). “We consume more than 1 million square meters of CFRP [carbon fiber-reinforced polymer] per year,” Álvarez says.

Today, the plant’s product portfolio includes the upper and lower HTP skins for the A320/A320neo and A330/A330neo, the front and rear spars for the A330/A330neo, the lower wing covers (also called wing lower covers, or WLC) and Section 19 for the A350, and the wing skins, front spar and wing tip spar for the EuroFighter-2000.

Wide-ranging goals: From ramp-ups to sustainability

“Our strategy is to work on what we call steps toward more composites within aircraft, and the A350 was a big step,” Álvarez explains. The impetus for increasing composites use is, of course, weight savings, which leads to less overall fuel consumption by the aircraft.

With its current commercial aircraft, Airbus as a whole, including the Illescas facility, is focused on preparing production capacity for its planned ramp-ups. Affecting the Illescas plant are increasing rate targets for the A320 (ramping up from 45 to 75/month in 2027), the A330 (ramping up from 3 to 4/month by the end of 2024) and the A350 (ramping up from 6 to 12/month in 2028). For all of these, the Illescas plant is “preparing the industrial means and processes to achieve these rates,” Álvarez says.

Alongside these ramp-ups, the company is also working toward the development of its “next-generation” aircraft. Looking ahead, the company’s top drivers, Álvarez says, are “driving down costs, increasing productivity of our industrial systems, quick ramp-ups and contributing to sustainability.”

With each of these drivers in mind, she explains that the top two priorities for Airbus’ next-generation commercial aircraft designs are, first, replacement of a single-aisle narrowbody aircraft, and second, its announced ZEROe short-range hydrogen-fueled electric aircraft, which is aimed to fly by 2035.

“For both of these, we expect to have a high rate of composites content to save weight. Low weight is key to fuel savings, especially if we want to onboard H₂ [hydrogen] tank systems. Whether we use H₂ or SAF [sustainable aviation fuel] for the narrowbody, weight will still be key and composites are likely to be key enablers of the next generation,” Álvarez says.

The Illescas facility in particular is working on solutions to improve next-generation aircraft efficiency, including R&D work on enhanced materials and processes, with a focus on ensuring sustainability.

Regarding its sustainability goals, about 4 years ago, Airbus changed its company motto from “We make it fly” to “We pioneer sustainable aerospace for a safe and united world.” “This change to me is a clear signal that we as a company want to join what we are doing in the present with the future,” Álvarez says. “We have to lead the ecosystem in not only being the best in what we do in our current and future products, but to lead the ecosystem around us with this focus on sustainable aerospace.” The company also supports industry targets such as EU Green Deal objectives for carbon neutrality by 2050 and a 55% reduction in CO₂ emissions by 2030.

“Composite materials might be a minor part of our overall carbon footprint today, but as we increase composites usage on future aircraft, the footprint will grow, especially as we reduce operation emissions by switching to hydrogen or SAF,” Blanco says. “We are fully committed to developing the ecosystem to enable recyclability of composites production scrap and end-of-life parts, and to work with suppliers to reduce the emissions of raw materials.”

In Illescas, sustainability efforts include working toward greater machine efficiency, looking for materials recycling solutions including several ongoing R&D projects and reducing waste, which involves the installation of a rainwater recovery system to feed into the cleanroom climate control system and nondestructive testing (NDT) equipment. For more details on the company’s sustainability initiatives, see companion article, “Airbus works to improve the lifecycle of composites in future aircraft.”

Predictive factory, empowered workforce

How is the plant working toward greater efficiency? “Our ambition is to become a predictive factory,” Álvarez says. “We as an industry have a lot of scrap and quality costs because we inspect the product at the end of the manufacturing process, but we need better ways to detect and predict defects earlier on, before the entire part is made, when there is still an opportunity to fix the problem.”

This includes implementation of various types of sensors on all machines and levels of the manufacturing process, to connect each stage of the process, provide information for the development of digital twins and ultimately provide “smart alerts” that anticipate any problems or defects and let the operator know so that the process can be stopped and corrected before it goes any further.

“Building a predictive factory is our ambition, and in my case, it’s like an obsession,” Álvarez says. “I prefer to say it’s a ‘data-driven factory’ instead of the word ‘digitalization.’ I don’t just want digital screens in the factory, I want a process that uses data to anticipate issues and optimize the process.”

Another set of goals Álvarez has for the Illescas facility is growing, diversifying and empowering its workforce. Currently, the facility numbers around 700 employees, with plans to grow as aircraft production ramps up. The average age for employees is 42 with 14 years of experience. Álvarez notes that gender diversity is something they are actively working toward — currently, women comprise 21% of the plant’s white collar employees, 12% of blue collar employees and 66% of engineering management. And of course, the overall plant itself is woman-led with Álvarez at the helm.

The Illescas plant also has what’s called an autonomous production team (APT), which is “a team of blue collars and supervisors that are empowered to make decisions on their own. For us, it was one of the biggest cultural transformations here,” Álvarez says, “a transformation to take improvement and optimization decisions down to the lowest level.”

As the CW tour moves out of the conference room and onto the production floor, Álvarez sums up, “Highlights of the plant include ramping up, boosting this predictive factory, working on sustainable solutions, improvement of the products with our steps and also working on R&D projects for the next-generation aircraft. This is more or less what we are doing now in the plant.”

Touring the A350 WLC facility

The Illescas facility comprises two production buildings. The first production facility CW had the chance to walk through is the newer, 64,988-square-meter building completed in 2011, which houses production for the A350 WLC.

Each cover comprises a skin reinforced with 17 stringers. To show how this process is done, Álvarez and Blanco lead the CW tour into a massive, open cleanroom. First, we walk into a space called the control room, where the team holds daily meetings and tracks progress via a SQCDP (safety, quality, cost, delivery and people) board on the wall. This is where the APT meets as well. Here, Álvarez explains that the wing covers, measuring 32 meters long and weighing 2,700 kilograms, are the largest CFRP part on the A350.

It’s worth noting that, due in part to the large space and large machines and parts, there appear to be few people around as we are walking through the cleanroom. Álvarez says that this is because the process is highly automated, about 70% for the A350 WLC core processes. About 50 employees are on the production floor at any given shift, most of them operating the automated equipment.

AFP and ATL layup

Leaving the control room, we first approach three gantry-style MTorres (Torres de Elorz, Spain) ATL machines. At current rates, only two of these machines are needed to lay up the WLC’s exterior layer of expanded copper foil for lightning strike protection (LSP). Four gantry-style MTorres AFP machines are then used to lay up the carbon fiber/epoxy prepreg for the skins themselves onto 3D Invar tools.

Why is ATL used for the LSP but AFP for the skins? Álvarez explains that AFP is much faster, able to lay down material at a rate of 50 kilograms/hour — versus the ATL’s rate of 20 kilograms/hour — which is more suitable for the skins, especially to meet ramp-up goals. The current foil used for LSP is also more suited for use with ATL, which processes wider tapes up to 300 millimeters (11.8 inches).

Airbus has worked on optimizing its AFP process further, and is switching its machines from 12.7-millimeter-wide (0.5-inch) tapes to 50.8-millimeter-wide (2-inch) tapes to increase efficiency. “Our first step is increasing the width capability of the AFP machines. For the next generation, we want to consolidate these processes and use one [AFP] machine, with wider and thicker CFRP materials for a higher deposition rate,” Blanco adds.

After layup, the skins are transferred out of the cleanroom for their first autoclave cycle, then brought back in for integration with the stringers.

Stringer forming and integration

Simultaneously with skin layup, the stringers are manufactured in a highly automated work cell on the far side of the cleanroom. There are 17 T-shaped stringers manufactured per wing skin, with varying lengths up to 32 meters.

The 32-meter-long stringer forming cell starts with two cantilever, 2D placement Torresfiber AFP machines to lay up tailored blanks for the stringer preforms, with trimming done on a nearby Torrespanex cutting system, both supplied by MTorres. The blanks are then preformed in a hot drape forming (HDF) machine and, after cooldown, are ready for integration onto the skins. Robotic arms move the stringers from one position to another.

Blanco explains the purpose of an extrusion machine seen to one side of the stringer forming cell: Leftover prepreg tape rolls are spliced via a KUKA (Augsburg, Germany) robot and then extruded into triangular fillers and noodles that are used to help position the T-stringers onto the skins.

We watch an AGV train move past carrying a wing skin tool, headed toward the exit door toward the adjacent autoclave area, where there are two vacuum bagging stations. Here, stringer preforms are placed via laser projectors and attached with adhesive to the skin. The entire assembly is then vacuum bagged and sent back into the autoclave for its final cure.

Autoclave, finishing, inspection

The tour continues from the cleanroom into the autoclave area, where there are two 40-meter-long, 7-meter-diameter autoclaves for curing both the skins and final WLC assemblies.

Beyond these are a series of four trimming stations, two on the right and two on the left, which employ laser scanners to check for dimensional accuracy, as well as assembly stations and two paint booths.

The final part is trimmed, drilled — 29 manholes must be cut into it for maintenance — assembled with gaskets and supports, and painted with primer. Airbus also performs visual and C-scan inspection here. The final parts are now ready for assembly into the A350 wings.

Transport for final assembly

How are the 32-meter-long wing components transported to the assembly facility? Álvarez explains, “We can transport them via truck as far as our facility in Getafe,” which is about 15 kilometers away — though she adds, “We have to close the road while we’re transporting them, so we can only do this at night and everything has to be highly controlled and coordinated ahead of time.” From Getafe, the WLCs are loaded onto Airbus’s Beluga transport aircraft to travel to Airbus facilities in Broughton and from there to the Airbus final assembly line (FAL).

From a sustainability perspective, Blanco adds that they switched from using the standard Beluga — capable of carrying two skins at a time — to the Beluga XL, which can carry four skins at a time (two right-hand and two left-hand, or skins for two aircraft), to help decrease transport costs and associated CO₂ emissions. The Beluga XL is also designed to run on SAF.

Touring the Section 19 facility

From here, the tour continues outside and to the nearby Section 19 building, moving first into another large cleanroom and into a control room similar to the one in the WLC building. “These control rooms are the same in all of our composites production facilities,” Álvarez says. She explains that the Section 19 is a fuselage barrel piece measuring 5.7 meters in length and about 4 meters in diameter, using 589 kilograms of carbon fiber prepreg to cover 53 square meters of surface area. In this building, Section 19s are manufactured for the A350-900 and -1000, as well as the newer A350 freighter.

This is the first composite Section 19 barrel Airbus has produced in one shot, and was one of the main goals in the design process — the A380 Section 19 was manufactured in six pieces that were joined together. Another design challenge was that this part of the fuselage has to handle complex loads from the HTP and vertical tail plane (VTP), which led to the materials choice of carbon fiber composites. The core processes for manufacturing this Section 19 have been automated about 60% so far, Álvarez adds.

Outside the control room are two ATL machines and a Torrespanex cutting machine, all supplied by MTorres. These are used to lay up 42 omega-shaped stringers per Section 19, again made from Hexcel carbon fiber/epoxy prepreg.

Next, the stringer plies are transferred to one of two nearby HDF machines for forming into the 6 × 2-inch-wide stringers. An autonomous AGV can be seen driving past, delivering the omega stringers across the room to one of two vertical storage warehouses. The process is similar to the WLC stringer forming process, albeit differently shaped tools and stringers; however, for the Section 19 fuselage, ATL layup is used versus AFP.

Beside the HDF lines and in the far corner of the space are two AFP stations — one by MAG (now owned by Fives) and one by Fives (Paris, France) — which lay up the skin onto an aluminum barrel mandrel designed by Airbus and manufactured by an external supplier. The skin is also transferred to the integration station, where stringers are pulled out of the storage warehouses and fitted by hand into specially designed channels in the mandrel. The entire assembly is then vacuum bagged for curing.

Autoclave, finishing and inspection

The tour continues into the next room, following the process to the autoclave area, which contains one autoclave and one demolding station. The sheer size of the parts is on full display here, with a row of finished Section 19 barrels seen on the far side of the space, perched on jigs and awaiting inspection.

The entire Section 19, including skins and stringers, is co-cured in one shot. Álvarez notes that the demolding process is “tricky,” requiring a specially designed process and controlled cooling for removing the part without damage. “The part keeps the same size after cure while the mandrel shrinks during cooldown. That makes it possible to separate the part from the tooling,” she explains. Six carbon fiber composite caul plates are used per mandrel to maintain outer surface dimension control.

To the left of the demolding area is a dust-controlled room where holes, for attaching frames and hardware during the assembly process, are drilled via a waterjet trimming station. Álvarez notes that the facility is looking for solutions with local partners for reuse of the trimming scrap.

The tour also enters the operator control area of a PAR Systems (Saint Paul, Minn., U.S.) robotic cell, where we can see a Comau (Grugliasco, Italy) robot that uses a diamond-coated tool to precisely cut holes into the stringers where fuselage frames will be attached with clips.

Each completed Section 19 is inspected in a two-step process, starting with a single-side, automatic phased-array ultrasonic NDT cell. Non-accessible areas are inspected manually via pulse echo ultrasonic testing (UT). In the second step within an adjacent manual inspection cell, the entire jig rotates around the person doing a visual inspection for better ergonomics. Finally, the parts are ready for transport and final assembly.

Preparing for the future

As the tour concludes, Álvarez emphasizes the ways both the WLC and Section 19 processes we witnessed circle back to Airbus’ larger goals and those of the Illescas plant in particular. “At every stage of the process, we’re implementing predictive sensors, because this data is how we’ll make our processes more efficient and meet both our sustainability and rate targets. On every team, we’re aiming for diversity and empowerment. We’re constantly reevaluating and improving the automation you see across the factory. It’s all about improving what we have now and preparing for what comes next.”