The WeCare project (Utilizing Weather information for Climate efficient and eco efficient future aviation), an internal project of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR), aimed at finding solutions for reducing the climate impact of aviation based on an improved understanding of the atmospheric impact from aviation by making use of measurements and modeling approaches. WeCare made some important contributions to advance the scientific understanding in the area of atmospheric and air transportation research. We characterize contrail properties, show that the aircraft type significantly influences these properties, and how contrail-cirrus interacts with natural cirrus. Aviation NO_x emissions lead to ozone formation and we show that the strength of the ozone enhancement varies, depending on where within a weather pattern NO_x is emitted. These results, in combination with results on the effects of aerosol emissions on low cloud properties, give a revised view on the total radiative forcing of aviation. The assessment of a fleet of strut-braced wing aircraft with an open rotor is investigated and reveals the potential to significantly reduce the climate impact. Intermediate stop operations have the potential to significantly reduce fuel consumption. However, we find that, if only optimized for fuel use, they will have an increased climate impact, since non-CO₂ effects compensate the reduced warming from CO₂ savings. Avoiding climate sensitive regions has a large potential in reducing climate impact at relatively low costs. Taking advantage of a full 3D optimization has a much better eco-efficiency than lateral re-routings, only. The implementation of such operational measures requires many more considerations. Non-CO₂ aviation effects are not considered in international agreements. We showed that climate-optimal routing could be achieved, if market-based measures were in place, which include these non-CO₂ effects. An alternative measure to foster climate-optimal routing is the closing of air spaces, which are very climate-sensitive. Although less effective than an unconstrained optimization with respect to climate, it still has a significant potential to reduce the climate impact of aviation. By combining atmospheric and air transportation research, we assess climate mitigation measures, aiming at providing information to aviation stakeholders and policy-makers to make aviation more climate compatible.

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.

Current practices for investment and technology decision making in aeronautics largely rely on regression-based cost estimation methods. Although quick to implement and easy to use, they suffer from a variety of limitations, both in temporal space and scope of applicability. While recent research and development in this area addresses these to a certain extent, aerospace engineering still lacks a flexible and customizable valuation framework. To this end, a generic environment for economic and operational assessment of aircraft and related products named LYFE is presented. This tool employs a discrete event simulation which models the product life cycle from its order through decades of operation and maintenance until disposal. This paper introduces its key characteristics and default methods alongside its modular program architecture. The capabilities are demonstrated with a case study of on-wing engine cleaning procedures which are triggered by a customized decision making module. Thereby, the impact on engine health, fuel efficiency and overall economic viability is quantified. On the whole, the framework introduced in this paper can be used to analyze not only physical products but also operational procedures and maintenance strategies as well as specified decision making algorithms in terms of their impact on an aircraft’s or system’s life cycle.

With growing environmental awareness and the resulting pressure on aviation, ecological impact assessments are becoming increasingly important. Life cycle assessment has been widely used in the literature as a tool to assess the environmental impact of aircraft. However, due to the complexity of the method itself and the long lifespans of aircraft, most studies so far have made strong simplifications, especially concerning the operational phase. Using a combined discrete-event simulation framework, this paper aims to ecologically assess the individual life cycle phases of an aircraft. The method will be demonstrated in a case study of an A320 and subsequently compared with findings from the literature. Despite the significant environmental impact of flight operations, which covers almost 99.8% of the entire life cycle of the aircraft, a detailed consideration of all life cycle phases is essential to serve as a reference for the ecological assessment of novel aircraft concepts. The presented assessment method thus enables a holistic analysis at an early stage of the design process and supports the decision-making for new technologies and operational changes.