The concept of a circular economy is centered around keeping materials and products in use for as long as possible. The Save Our Seas 2.0 Act defines a circular economy as one that prioritizes a systems-focused approach, involving restorative or regenerative industrial processes and economic activities. The goal is to maintain the highest value of resources for as long as possible and eliminate waste through superior design of materials, products, and systems. This represents a shift from the traditional linear model of resource extraction, production, and disposal. In a circular economy, material use is reduced, and materials and products are redesigned to be less resource intensive, with the aim of repurposing "waste" as a resource to manufacture new materials and products.
The concept of circularity aligns with the sustainable materials management (SMM) approach that the EPA and other federal agencies have been pursuing since 2009. Embracing a circular economy approach under the SMM umbrella demonstrates a commitment to reducing the negative lifecycle impacts of materials, including climate impacts, minimizing the use of harmful materials, and decoupling material use from economic growth while meeting society's needs. The EPA has a broad vision to address the full impacts of materials on our communities and has set out a transformative vision for waste management that is inclusive, equitable, and responsive to the urgency of the climate crisis. To achieve this, the EPA has released a series of strategies dedicated to building a circular economy for all.
The circular economy model in aircraft design, maintenance, and end-of-life management is an emerging and essential approach in addressing both economic and environmental concerns. This system strives to extend the lifespan of aircraft materials, minimize waste, and maximize the recycling and reuse of valuable components. By embracing circular economy principles, the aviation industry can significantly reduce its environmental impact, conserve resources, and enhance the economic value of materials through various stages of an aircraft's lifecycle.
The circular economy begins at the design and manufacturing stages, where aircraft parts are created using renewable and finite materials, with a preference for renewable energy. As aircraft are built, manufacturers increasingly incorporate design-for-disassembly principles, making it easier to maintain, repair, and recycle components at the end of the aircraft's service life. Aircraft parts, including engines, wings, fuselages, and electronic systems, are constructed with the understanding that they will eventually undergo remanufacturing, reuse, or recycling.
Once in service, aircraft maintenance plays a significant role in the circular economy. Maintenance providers and manufacturers work closely to extend the life of the components through regular upkeep, repairs, and refurbishments. For instance, CFM International's CFM56 engines, which power both narrow-body and wide-body aircraft, represent a key example of this maintenance loop. The engine's annual maintenance produces emissions equivalent to 75,000 tons of CO2 and consumes 3,500 tons of materials (FTAI, 2023). However, many of these materials can be recycled or refurbished, significantly reducing the need for extracting new resources.
Through efficient maintenance, parts that can no longer be used in their original function are remanufactured or sent for recycling. Reusable materials from engines and other components can be reintroduced into new products or other sectors, thereby closing the material loop. For example, nickel from aircraft engines can be recycled with carbon steel scrap for use in the production of stainless steel (Dubreuil et al., 2010). This closed-loop recycling reduces the need for primary nickel production, conserving raw materials and reducing energy use.
The circular economy reaches its full potential at the end-of-life (EOL) stage of aircraft. An estimated 10,000 passenger aircraft are expected to be replaced in the coming decades due to the increasing demand for newer aircraft (Ribeiro & Gomes, 2015). Traditionally, retired aircraft were stored in deserts, but the growing interest in recovering valuable materials from these planes has highlighted the potential for recycling.
At the end of an aircraft's service life, it undergoes a disassembly process. This involves the careful removal of hazardous materials (such as fuel and oils) followed by dismantling the aircraft into its individual components. The disassembled materials are then sorted into categories: reuse, recycling, energy recovery (incineration), and landfill. The recycling of aircraft components focuses on recovering as much material as possible, especially valuable metals and composites. For example, engines, which account for more than 60% of the aircraft’s total value, are highly recyclable, and their parts can often be remanufactured or melted down for material recovery (Zhao, 2021).
A key benefit of recycling retired aircraft is the reduction in demand for primary raw materials. This not only helps conserve finite resources but also lowers the energy requirements associated with mining and refining new materials. Recycling aircraft parts has been shown to significantly decrease energy consumption compared to producing new materials. For instance, disassembling and recycling aircraft engines is a profitable practice, with a higher Net Present Value (NPV) compared to dismantling an entire aircraft (Xiaojia et al., 2020).
Moreover, the environmental benefits of recycling extend beyond resource conservation. Recycling reduces waste sent to landfills and minimizes emissions associated with new material production. The process of reusing materials and parts decreases the industry’s carbon footprint, contributing to global sustainability goals. For instance, reusing and recycling engine components can prevent further CO2 emissions equivalent to the emissions of thousands of flights, as seen in the CFM56 engine case.
The successful implementation of a circular economy in aviation depends on strong regulatory frameworks and industry guidelines. Aviation authorities such as the International Civil Aviation Organization (ICAO), FAA, and EASA provide essential regulations to ensure the safe and environmentally responsible recycling of aircraft components. These guidelines cover everything from airworthiness regulations to waste management protocols (Scheelhaase et al., 2022). Additionally, organizations like AFRA (Aircraft Fleet Recycling Association) and IATA (International Air Transport Association) offer Best Management Practices (BMP), although these are voluntary guidelines aimed at improving sustainability in the industry.
These regulations and best practices ensure that aircraft disassembly, recycling, and material recovery are conducted in a way that maximizes both economic and environmental value. For instance, many certified waste management companies specialize in the disposal and recycling of various aviation materials, contributing to the overall success of the circular economy model.
Conclusion
The circular economy in the aviation industry represents a promising pathway to reduce environmental impacts, conserve resources, and improve economic outcomes through sustainable practices. From design and manufacturing to maintenance and end-of-life recycling, the circular model offers an effective way to minimize waste and reduce reliance on new material extraction. By recycling valuable components such as engines, aircraft manufacturers and operators can contribute to a greener, more sustainable future for the aviation industry. With continued regulatory support and industry collaboration, the circular economy will play an increasingly important role in the lifecycle management of aircraft.
FTAI, 2023. FTAI Aviation: ReCycle. [Online] Available at: http://view.ceros.com/fortress-investment/esg/p/1
Dubreuil, A., Young, S. B., Atherton, J. & Gloria, T., 2010. Metals recycling maps and allocation procedures in life cycle assessment. The International Journal of Life Cycle Assessment, 15(6), pp. 621-634.
Ribeiro, J. S. & Gomes, J. d. O., 2015. Proposed Framework for End-of-life Aircraft Recycling. Elsevier, ScienceDirect.
Xiaojia, Z., Verhagen, W. J. C. & Curran, R., 2020. Disposal and Recycle Economic Assessment for Aircraft and Engine End of Life Solution Evaluation, s.l.: MDPI, applied sciences
Scheelhaase, J., Müllera, L. & Ennena , D., 2022. Economicand Environmental Aspects of Aircraft Recycling, Published by ELSEVIER B.V.. Elsvier B.V, p. 10.