The early aircraft cabin was characterised by simple furnishings, mainly made of wood and rattan. There were luggage nets, insulation and seat belts were missing. As prosperity increased, so did comfort in the cabin, in the form of comfortable armchairs and insulation and thus the introduction of composite materials. Due to numerous aircraft accidents, the requirements for fire protection in aircraft have been tightened since the 1980s in order to increase the safety of uninvolved persons on the ground, passengers and crew. Natural and combustible materials had to give way to non-combustible materials.

Today, cabin structures are usually constructed from a duromer sandwich consisting of aramid honeycomb core and glass fibre reinforced cover layers (see Figure 1). Typical cabin structures feature a variety of different material classes, which form a mechanically strong bond with each other during the manufacturing process. Although there are already recycling options for all material classes individually, recycling is difficult and cost-intensive in reality due to the difficulty of separating the material groups and is therefore not economical.

In order to make cabin structures more sustainable, we should therefore start early in the process chain, when manufacturing the structures, with a particular focus on the choice of materials according to the following possible strategies: maximising the degree of lightweight construction (‘lightweight’), sustainably sourced materials (‘bio-based’) and improving recyclability. Equally important are sustainable design strategies such as Eco-Design or Design for Recycling .

Each of these strategies can contribute to a more sustainable aircraft cabin, but they are not yet complementary. Which of these strategies is preferable depends heavily on the framework conditions and requirements - and an evaluation can only be decided in a combination of economic and technical criteria, supported by well-founded life cycle analyses.

The challenge before us is to bring these strategies together in such a way that lightweight components can be manufactured on the basis of regenerative raw materials that can ultimately be recycled in such a way that the materials can be managed in a real cycle!