The increasing complexity and safety-critical nature of aircraft engines have made effective health monitoring and predictive maintenance essential in modern aviation systems. Turbofan engines operate under extreme conditions, where unexpected component degradation can lead to serious failures, high maintenance costs, and operational downtime. Traditional maintenance strategies, such as reactive and preventive maintenance, are no longer sufficient to handle these challenges efficiently. As a result, data-driven approaches based on machine learning and deep learning have gained significant attention in prognostics and health management (PHM) applications. This review focuses on health monitoring and remaining useful life (RUL) prediction of turbofan engines using advanced deep learning techniques. It examines how sensor data collected from aircraft engines can be utilized to detect degradation patterns and estimate future engine health. Particular emphasis is placed on hybrid deep learning models that combine feature extraction and temporal sequence learning, such as convolutional neural networks, autoencoders, and long short-term memory networks. The study also discusses publicly available benchmark datasets, especially the NASA C-MAPSS dataset, which is widely used for validating RUL prediction models. Key challenges such as data imbalance, noise, model interpretability, and real-time deployment are highlighted. Overall, this review demonstrates that deep learning-based prognostic models play a crucial role in improving prediction accuracy, enhancing aviation safety, and enabling reliable condition-based maintenance strategies for turbofan engines.
Introduction
The rapid expansion of the aviation industry has increased the need for safe, reliable, and cost-effective aircraft operations. Turbofan engines operate under extreme mechanical and thermal conditions, leading to gradual component degradation that can reduce performance, increase maintenance costs, and cause unexpected failures. Traditional reactive and preventive maintenance strategies are inefficient, prompting a shift toward condition-based and predictive maintenance. Prognostics and Health Management (PHM) supports this transition by enabling early fault detection, degradation assessment, and prediction of Remaining Useful Life (RUL) using sensor data collected during engine operation.
Recent advances in machine learning and deep learning have significantly improved turbofan engine health monitoring. Models such as Convolutional Neural Networks (CNNs), Long Short-Term Memory (LSTM) networks, Recurrent Neural Networks (RNNs), autoencoders, attention mechanisms, and hybrid or ensemble architectures are widely used to analyze multivariate time-series sensor data. CNNs are effective for feature extraction, LSTMs and GRUs capture long-term temporal dependencies, and hybrid models combine these strengths for improved accuracy. Ensemble methods further enhance robustness and generalization, while attention-based models and probabilistic approaches improve interpretability and uncertainty estimation.
The literature review highlights extensive use of the NASA C-MAPSS dataset as a benchmark for evaluating RUL prediction models. While deep learning approaches consistently outperform traditional methods, they face challenges such as high computational cost, data noise, class imbalance, overfitting, limited interpretability, and difficulties with real-time deployment. Techniques like sensor fusion, dimensionality reduction (e.g., PCA), autoencoder-based representation learning, and uncertainty-aware frameworks help address some of these issues, though trade-offs between accuracy, efficiency, and transparency remain.
Methodologically, turbofan prognostics typically follow a pipeline involving sensor data acquisition, data preprocessing, feature extraction or representation learning, temporal modeling, and performance evaluation. Deep learning has reduced reliance on manual feature engineering and improved the ability to model complex degradation patterns. Overall, the reviewed research demonstrates that data-driven and deep learning-based PHM systems offer strong potential for reliable RUL prediction and predictive maintenance in aviation, while future work should focus on improving interpretability, computational efficiency, uncertainty handling, and real-time applicability.
Conclusion
The increasing operational demands and safety requirements of the aviation industry have made effective health monitoring and predictive maintenance of turbofan engines a critical research area. This review examined recent advancements in data-driven approaches for engine health assessment and Remaining Useful Life (RUL) prediction, with a particular focus on machine learning and deep learning techniques. The surveyed literature demonstrates that traditional maintenance strategies are gradually being replaced by predictive models capable of analyzing multivariate sensor data to identify degradation patterns and forecast future engine behavior. Deep learning models, especially Long Short-Term Memory networks, convolutional architectures, and hybrid frameworks, have shown strong performance in capturing complex temporal relationships within sensor data. The use of publicly available benchmark datasets such as NASA’s C-MAPSS has enabled consistent evaluation and comparison of different prognostic methodologies. However, several challenges remain, including high computational complexity, limited interpretability of deep models, and difficulties in real-time deployment under varying operational conditions. This review highlights the need for more robust, explainable, and scalable predictive maintenance solutions that integrate domain knowledge with data-driven techniques. Future research should focus on improving model transparency, incorporating uncertainty estimation, and optimizing computational efficiency to support real-world aviation applications. Overall, advanced prognostic models hold significant potential for enhancing aircraft safety, reducing maintenance costs, and enabling reliable condition-based maintenance strategies for turbofan engines.
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