The problem the team set out to solve is rooted in materials chemistry. Modern aircraft increasingly rely on carbon fiber reinforced plastic, which can cut component weight by 25 to 30 percent compared with aluminum, and on even lighter sandwich panels for less load-bearing structures. But the resins that hold these composites together, known as thermosets, cure permanently and cannot be re-melted or remolded. When a thermoset sandwich shell reaches the end of its life, it is essentially destined for landfill. Thermoplastics such as polyphenylene sulfide and polyetherimide behave differently: they soften when heated, which means components made from them can theoretically be welded, reshaped, and mechanically recycled. As part of the European Union’s Clean Aviation research program, engineers have been developing rudder designs built around exactly these recyclable materials, with service entry expected around 2030.

Recyclability alone, however, does not guarantee a greener part. The researchers point to the risk of burden shifting, a phenomenon in which higher impacts during manufacturing cancel out gains at end of life. To avoid that trap, they applied life cycle assessment, an ISO-standardized method that quantifies environmental impacts from raw material extraction through production, use, and disposal. Crucially, they went a step further than conventional studies by using prospective LCA, a variant that models how the broader energy system and society will evolve over the decades an aircraft part remains in service. Using the premise framework, they adjusted background databases to reflect the REMIND integrated assessment model under the Shared Socioeconomic Pathway 2, a middle-of-the-road global trajectory, with climate limits aligned to national commitments. Two alternative energy futures, one greener and one dirtier, were tested as well.

The functional unit was deliberately precise: controlling the yawing motion of an Airbus A320, meaning rotation around its vertical axis, for 20 years, corresponding to one rudder over the aircraft’s lifetime. Three designs were compared. The incumbent rudder uses thermoset composites and adhesive materials, including aramid and epoxy plastics. Two ecodesign variants replace the sandwich shells with thermoplastic versions, one based on PPS and one on PEI, each paired with different carbon fiber face sheets and plastic cores. The team collected primary data directly from technology developers, disaggregating sandwich shell manufacturing into five process steps, and generated 92 novel, openly available life cycle inventory datasets, published in a public repository so that other researchers can reproduce and extend the work.

The headline finding is that aircraft operations dominate the environmental picture. More than 95 percent of the rudder’s lifetime impacts come from the use stage, driven overwhelmingly by fuel burn, which accounts for 70 to 78 percent of ecosystem quality and human health damage, with fuel production contributing another 22 to 29 percent and maintenance less than 1 percent. Because the thermoplastic sandwich shells weigh less than their thermoset counterparts, the ecodesign rudders burn proportionally less fuel, delivering the 6 percent reduction in operational impacts. The researchers stress-tested this result with a sensitivity check of plus or minus 25 percent on the allocation factor that assigns fuel to the rudder based on its mass fraction of the aircraft, and the ranking of designs held firm.

Zooming in on manufacturing and end of life, where materials choices matter most, the ecodesign rudders showed 42 to 80 percent of the incumbent’s impacts, averaging 72 plus or minus 9 percent across midpoint impact categories. The largest single contributor to the improvement was the sandwich shell itself: ecodesign shell manufacturing achieved 59 to 65 percent of the incumbent’s impacts for ecosystem quality and human health damages, thanks to the switch from aramid and epoxy plastics to PEI and PPS, which carry lower impacts per kilogram. In freshwater and marine eutrophication, the ecodesign rudders fell below half the incumbent’s impact. At the end of the rudder’s life, the thermoplastic shells are assumed to undergo mechanical recycling after a delamination process separates the face sheets from the core, with the recovered plastic credited against virgin thermoplastic production in 2050, whereas the incumbent shell is landfilled.

To test whether these advantages were robust rather than artifacts of optimistic assumptions, the team ran a Monte Carlo simulation of 1,000 runs, incorporating uncertainties in component weights, electricity use, and polymer production data. The result was emphatic: the ecodesign rudders showed a 99 to 100 percent likelihood of lower impacts than the incumbent for both human health and ecosystem quality damage indicators. A global sensitivity analysis revealed where better data would help most. Half of the ten most sensitive inputs related to electricity used in manufacturing the carbon fiber face sheets, and the next group involved the polymers themselves, whose production inventories range widely in the literature. Carbon fiber, in particular, carries reported climate impacts spanning 10 to 90 kilograms of carbon dioxide equivalent per kilogram; this study calculated 76, and found it responsible for roughly half of the climate change impacts of rudder manufacturing, given energy-intensive production in China, where coal still supplies about 40 percent of electricity in the 2030 scenario.

The damage-level analysis offered a caution about looking beyond carbon. Climate change drives about 58 percent of human health damage and 40 percent of ecosystem quality damage in these rudders, so decarbonizing energy inputs remains the highest-leverage intervention. Yet 42 percent of ecosystem quality impacts stem from other categories, including freshwater ecotoxicity linked to coal power, land transformation from photovoltaic installations in China and the EU, and terrestrial acidification driven largely by sulfur oxide emissions. This means that mitigation strategies can create trade-offs: for example, expanding solar power reduces carbon emissions but increases land use impacts. The study argues that aircraft manufacturers should systematically assess a broad portfolio of impact categories rather than focusing narrowly on climate change, in order to avoid simply moving environmental burdens elsewhere.

Looking ahead, the researchers modeled three additional innovation scenarios for the PPS-based ecodesign rudder: increased recycling, in which production cuttings are re-melted into new cores and end-of-life recycling rates match common plastics; halved energy demand at the thermoforming step; and ambitious material changes across the rest of the rudder, including minimizing titanium use and converting more thermoset parts to thermoplastics. Combined, these measures could cut the rudder’s manufacturing and end-of-life impacts by a further 28 to 30 percent. Notably, the energy efficiency scenario delivered less than 1 percent improvement, because thermoforming is already a relatively low-impact process. The real prize lies in end-of-life recovery, suggesting that engineers should prioritize designing for recyclability over squeezing further efficiency from production lines.

The study distills three actionable recommendations for aircraft designers. First, sustainability assessments must cover the entire life cycle, because use-stage fuel savings, however small they appear at the component level, dominate the environmental ledger. Second, designing parts for recovery and recycling at end of life offers substantial additional reductions, and thermoplastics make that possible for the first time in composite aerostructures. Third, environmental evaluation should extend beyond climate change to catch trade-offs as renewable energy adoption reshapes the impact profile of manufacturing. With 92 reproducible inventory datasets now publicly available, and with sandwich shells also used in wings and other structures, the rudder study provides both a methodological template and a concrete evidence base for the greener aircraft the industry has promised for 2050. The authors note that economic analyses, including life cycle costing, will be needed to confirm whether fuel savings outweigh manufacturing costs, but on the environmental balance sheet, the recyclable rudder has clearly earned its place in the flight plan.

Subject of Research: Prospective life cycle assessment of a thermoplastic composite aircraft rudder redesign

Article Title: Prospective life cycle assessment of redesigned airplane rudder with thermoplastic composites

Article References: Bechu, A. M., Lüttmann, H., Hilgers, R., Winant, W., Pflug, J., Wüstenhagen, S., Schlimper, R., Huth, H. M., & Laurent, A. (2026). Prospective life cycle assessment of redesigned airplane rudder with thermoplastic composites. Journal of Industrial Ecology. https://doi.org/10.1007/s44498-026-00172-3

Image Credits: AI Generated

DOI: 10.1007/s44498-026-00172-3

Keywords: aviation, thermoplastic composites, life cycle assessment, aircraft rudder, recycling, carbon fiber, ecodesign, sustainable aviation, environmental impact, sandwich structures, Clean Aviation, burden shifting