# Disposal and Recycle Economic Assessment for Aircraft and Engine End of Life Solution Evaluation
## 3 Scenarios and Process Detail
### Aircraft Disposal and Recycle Process
Disassembly includes components removal and cannibalization for component management, while dismantling refers to material cutting and shredding for further recycling. Several strategies, such as systematic disassembly, shredding, smart shredding, gross cutting, semi-gross cutting, detail cutting, smart disassembly, and disassembly combined with cutting, can be utilized to accomplish the disassembly and dismantling [16]. The systematic disassembly will result in all the components and attachments being separated, removed, and sorted by material compositions. While shredding  
Figure 2: Aircraft disposal and recycle process model. pertains to cut the aircraft being dissected into small pieces with mixed materials. Various techniques of shredding, such as magnetic, eddy-current, and sink-float separations, are employed depending on different material types [41]. Other strategies are intermediate solutions balancing costs and benefits of the operations. Component management and material management are performed respectively, and could be conducted concurrently for different parts of an aircraft. In one way, component management removes valuable components, which can then be sold and reused on other aircraft or for alternative reuse. Note that, for a component to be reused on another aircraft of the same model and sustaining of its original function, the component needs to be cleaned, repaired, and revertified to satisfy the regulations of an operational aircraft. If it is reused alternatively without sustaining its original primary function (e.g., for product exhibition), it needs to be reworked and remanufactured. On the other hand, material sorting and separating, referred as material management, are conducted after removing and scrapping hazardous materials. The sorted and separated materials are used for secondary recycling based on material properties and available recycling techniques. The secondary recycling is distinguished from the primary recycling for materials that are scrapped during the aircraft production processes [7]. In general, metal, glass, composite, and plastic materials are separated. Based on their sizes and recycling techniques, different materials are supplied for respective recycling processes. For example, Al metal parts are firstly grouped by aluminum main families (Al 2 xxx and 7 xxx) with similar sizes. Then, those clean and sorted parts or shredded chips can be melted to be reformed to foundry parts. The composite parts, such as Carbon Fiber Reinforced Plastic (CFRP) material, can be decomposed to extract the pure carbon fibers. Those carbon fibers can then be treated as recovering materials for new components. The components are usually non-structural parts or parts for automotive components or for electronic instruments. Two types of secondary recycling processes are categorized in terms of the quality of the recovered materials. Some are recycled without losing the material quality, while others are recycled due to containing paint/glue or recycled by the immature recycling techniques, which is also denoted as down-cycling. If the material cannot be recycled but can be burnt as wastes, the incineration process will then convert the burning energy to heat or electricity, so-called energy recovery. In an ecological hierarchy, the last choice would be land filling when the part/component material cannot be reused, recycled, nor used for energy recovery. Taking a Boeing 737 D&R case as an example, the following process flow can be constructed: The aircraft is purchased and transported to the disposal site; then, the systems, such as air conditioning, auto flight and electrical power systems, are removed, and the engine and landing gear are also removed. Next, some systems and engine parts are repaired, recertified, and reused for the other aircraft; the landing gear is scrapped; the airframe is shredded and the materials are sorted to be further recycled as recovered material.