Tim Hoff

Aircraft engine maintenance planning is traditionally focusing on questions of economic optimization. This includes repair-versus-replacement decisions and the cost-effective scheduling of maintenance events and relies on operational data, shop visit forecasts, and contractual obligations. Although this approach has been subject of extensive study, the integration of environmental considerations into maintenance planning remains largely overlooked. For example, replacing Life Limited Parts (LLPs) in shorter intervals can improve engine efficiency and reduce fuel consumption, but increases material demand and lead to a higher number of shop visits, causing additional environmental impacts. Postponing replacement conserves resources but may lead to higher operational inefficiencies and greater fuel consumption. Therefore, the objective of this study is to examine the environmental consequences associated with the timing and frequency of LLP replacements. Furthermore, it analyses the impact of different replacement intervals on climate change, material resource consumption and engine performance. A comparative Life Cycle Assessment (LCA) study is conducted to quantify the environmental impacts of replacing LLPs at shorter intervals versus an optimized replacement interval. By varying the LLP usage, this study demonstrates how longer utilization influences the overall environmental impacts. These repercussions are compared to increased fuel consumption due to engine degradation by using a simplified engine performance degradation approach. The findings of the study indicate the significance of varying impacts of different replacement intervals on the overall environmental performance. Furthermore, the study underscores the importance of recycling strategies for improving resource efficiency and sustainability in engine maintenance.

Hydrogen is one of the most promising power sources for meeting the aviation sector’s long-term decarbonization goals. Although on-board hydrogen systems, namely, fuel cells, are extensively researched, the maintenance, repair and overhaul (MRO) perspective remains mostly unaddressed. This paper analyzes fuel cells from an MRO standpoint, based on a literature review and comparison with the automotive sector. It also examines how well the business models and key resources of MRO providers are currently suited to provide future MRO services. It is shown that fuel cells require extensive MRO activities and that these are needed to meet the aviation sector’s requirements for price, safety and, especially, durability. To some extent, experience from the automotive sector can be built upon, particularly with respect to facility requirements and qualification of personnel. Yet, MRO providers’ existing resources only partially allow them to provide these services. MRO providers’ underlying business models must adapt to the implementation of fuel cells in the aviation sector. MRO providers and services should, therefore, be considered and act as enablers for the introduction of fuel cells in the aviation industry.