Recent advancements in deep learning for aircraft engine fault detection have been predominantly focused on research using simulated datasets. Despite significant progress, the gap between simulated and real-world data underscores a pressing need for models that are more applicable and adaptable to the aerospace industry. This discrepancy stems from factors such as water washes, maintenance activities, noise, and nuanced variations in operating conditions. Further complicating this issue is the lack of failure data leading to class imbalance and limiting the performance of fault classification models. In response to these challenges, this study uses Generative Adversarial Networks (GANs) to augment real-world failure data from General Electric Next Generation (GEnx) aircraft engines. New synthetic data are generated using a Wasserstein GAN with Gradient Penalty (WGAN-GP) and convolutional layers. Evaluation of GAN-generated data remains an active area of research. Accordingly, we also introduce a novel validation method based on a GEnx Gas Path Analysis model. This evaluation step revealed that the GAN could effectively generate gas path response variables that were physically meaningful and consistent with the operating conditions. Furthermore, integrating the GAN-generated data into the original dataset improved the baseline fault detection model’s F1-score by an average of 2.8%. This research also highlights the GAN’s ability to learn and reproduce degradation patterns applicable across different engine units, emphasizing its potential to overcome the challenges between engine unit-to-unit variations. Additionally, this work can potentially be extended to other engine families that require synthetic data to improve maintenance strategies.

The increasing demand for sustainable aircraft solutions has encouraged the development of non-CO􁊼 emitting aircraft designs. Currently, a number of theoretically successful designs have been created by parties such as the Massachusetts Institute of Technology, National Aeronautics and Space Administration, and The Technical University of Delft. Unfortunately, these radical aircraft redesigns are too risky to conceive, requiring massive amounts of investment and research. Since growth of the global aviation industry will only persist if aircraft greenhouse gas emissions are reduced, airlines have been looking for more fuel efficient aircraft, and the demand for green solutions has skyrocketed1. Thus, in this study the A320appu is proposed in an effort to significantly decrease the environmental footprint of aviation while limiting the risks and cost that accompany novel designs. This is done trough a conversion of the A320neo to use a hybrid, multi-fuel power and propulsion system. By replacing the traditional kerosene Auxiliary Power Unit (APU) with a hydrogen engine and an aft mounted, boundary layer ingesting propulsor, the design will enter the narrow-body market as an intermediate step between current generation kerosene-powered aircraft and more distant radical redesigns, like the Flying V2 or the Aurora D8 3. The APU is thus adapted into an Auxiliary Power and Propulsion Unit (APPU). This single aisle, short-medium haul airliner was specifically chosen for this conversion because aircraft of this class are expected to comprise 80% of all aircraft sales by 2038. The reconfigured A320neo, coined the A320appu, shall provide an economically feasible and green alternative. It shall be the first advance towards normalising hydrogen within the aviation industry.

The challenges of designing the A320appu are to maintain low development costs, integrating the cutting edge subsystem and reassessing aircraft parameters such as the stability and controllability or range. Moreover the Operating Empty Weight (OEW) increases because of the added subsystems, and as the A320appu is designed for the same Maximum Take-off Weight (MTOW), the available payload decreases. The A320appu is designed such that the increase of the OEW is minimised, while maximising the integrability by limiting the amount of changes to the A320neo. Furthermore, significant reduction of the 𝐶𝑂􁊼 emissions and local pollution have to be ensured, while providing similar performance to the A320neo. To achieve the aforementioned points, four main changes to the A320neo are proposed below and thereafter discussed in more detail.