Across the world, the aviation industry is looking for ways to become more sustainable.

Article featured in the latest issue of the AMRC Journal.

While work is advancing on in-flight emissions, from reducing aircraft weight, to creating sustainable fuels, one area is often overlooked - the cabin itself. While much of the structure of an aircraft is governed by strict regulations, the interior is less safety-critical, providing an as-yet-untapped opportunity to make major improvements to the design and supply chain.

Currently, passenger seats are replaced several times throughout the life of a plane. The old seats are typically discarded, creating tens of thousands of tonnes of waste material lying in ‘aircraft graveyards’. Looking at how these components can be recycled, there’s a large opportunity in introducing circularity systems into the supply chain. In other words, can aircraft seats at the end of their life be recycled into new seats? And is this both feasible and economically viable?

The AMRC wanted to find out.

The design phase of a product life cycle is critical, as it is during this stage that the factors which determine environmental impact are largely set in place, so it’s key to improving both operational and non-operational sustainability.

The project, commissioned by the High Value Manufacturing (HVM) Catapult, recognised the strategic importance of circularity in aerospace supply chains. Engineers at the AMRC’s integrated manufacturing group designed and ran a discrete event simulation (DES) - a computer model which tests how a new, complex system or network will work. It is a  powerful tool, which can be used to evaluate the impact of making changes to the aircraft cabin supply chain over time, and takes into account many different factors, and can even include uncertainties - analysing statistically the consequences of various processes. It provides a risk-free environment to gain deep insights and to test decisions before making changes in real-life manufacturing operations.

Simulating the future

The simulation assessed and compared different ways of introducing recycling to the process of replacing aircraft seats, looking at material types, costs and quantities, and the emissions associated with producing each material.

Focusing their model on Western Europe, as there was sufficient data available through open-source databases for the aeroplane fleets across the region, the team first mapped a snapshot of the current state of play. This included how old each plane was, how the cabin of each aeroplane was configured, when the seats would require replacing, and when new seats would need to be produced to replace existing seats, or be put into new aircrafts. They were then able to run a simulation model for the next five years, taking into account each fleet’s need for new seats and new planes, and the reverse flow of retired aircraft and overhauled cabin seats.

Starting in August 2024, the five year simulation looked at material composition, costs and emissions. Engineers found that, due to the age of the fleet and increased production levels within Airbus, there is a need for around 250,000 new seats over the timeframe. Running various scenarios using different processes, from the current situation involving no recycling to a process where a recycling centre disassembled each seat and used the materials to make new ones, different types of materials were studied, looking at how they would affect the overall process and feasibility.

At the seat recycling centre, the materials - leather, foam, plastic, fabric and aluminium - are separated and processed. Recycled materials are then delivered back to seat manufacturers, reducing dependency on virgin raw materials. The percentage of recycled material incorporated into new seats, along with the resulting cost evaluation and emissions reductions, is all calculated within the AMRC’s model.

The simulation showed that it was possible to recover enough material to account for 70 per cent of that required for new seats, reducing carbon emissions in the process by more than half. It also showed that introducing the recycling element could be as financially profitable as the current system; a result vital in encouraging the industry to make the change.

A scalable solution

Through multiple scenario variations being tested, the team were able to present the most balanced scenario, chosen based on its environmental impact and cost-effectiveness, offering the most feasible and scalable solution within the scope of the study.

The research has therefore demonstrated that aircraft seat recycling is both feasible, and economically viable, marking a significant shift in how the aerospace industry approaches sustainability and waste management currently.

The results also suggest that establishing a centralised seat recycling centre in regions like Western Europe could streamline the supply chain and increase the feasibility of circular practices within the aerospace industry.

While this kind of simulation is often used in other sectors where recycling and circularity practices are well established, like automotive, it is still novel for the aerospace industry. The International Civil Aviation Organisation has said that the circular economy is still an emerging concept for the sector, and its application is not widespread, so there is scarce availability of reliable data. By providing a data-driven decision-making tool, this study can give the aviation sector the confidence to challenge traditional linear supply chain models, and support the transition to a circular economy in aerospace.

Global dissemination

The AMRC is now presenting its findings to its partner companies, including aerospace giants Airbus and Boeing and various seat manufacturers, as well as disseminating its findings at global conferences. The model is also on display on the AMRC Factory 2050 supply chain demonstrator wall, showcasing these insights to a wider audience, with an aim to change the way the sector plans and designs its future cabin interiors, ensuring that recycling and whole-life circularity is built into the process. 

Marco Franchino, lead engineer for manufacturing intelligence at the AMRC’s integrated manufacturing group, highlighted the project's potential for widespread applications. He said: "Working on this project has shown how simulation can turn complex sustainability challenges into practical insights.

“Our model highlights not only the environmental benefits of reducing emissions through recycling, but also demonstrates a viable business case for circularity, laying the groundwork for scalable solutions within aerospace and beyond."

While this study was focused on aircraft seats, the methodology used is adaptable to other components, both in the aerospace sector and beyond. The ultimate goal is to extend the use of this model in real-world case studies, fostering collaboration across industries to promote sustainable practices and quantify the benefits.

Future AMRC High Value Manufacturing (HVM) Catapult projects, scoped in collaboration with Victor Guang Shi,  supply chain resilience lead at the AMRC, will build upon the knowledge gained during this project. As part of the HVM Catapult, the AMRC will look at investigating the traceability aspects of the digital thread and the use of intelligent artificial intelligence (AI) and machine learning (ML) towards future supply chain mapping and assessment, to mitigate risks and enhance networks.

Although, by its nature, the simulation includes a number of assumptions, it is a valuable tool to stimulate discussion about the potential  business case for changing the way seats are made for aeroplanes. For all the industry’s work on lightweighting and fuel composition to deliver on its mission to be more sustainable, perhaps part of the solution was sitting underneath us the whole time.