Reliability-driven depreciation modelling for aircraft engine life-limited parts

The valuation of aircraft engines in the secondary market is critically influenced by the condition and remaining life of their Life-Limited Parts (LLPs). Traditional approaches often rely on fixed depreciation coefficients that fail to reflect the true operational history or probabilistic risk of failure. This study proposes a lifecycle-aware valuation framework based on Weibull-distributed failure modelling, enabling the computation of adaptive cost reduction coefficients for individual LLPs. Using simulated and operationally realistic data, the model estimates reliability-driven depreciation curves and quantifies residual value degradation over time. Comparative analysis confirms that the Weibull distribution provides superior flexibility and interpretability compared to alternative statistical laws. The methodology captures nonlinear wear-out dynamics and supports the generation of part-specific valuation profiles. The resulting insights enhance the accuracy and transparency of engine appraisal, teardown pricing, and leasing negotiations. This approach offers a practical foundation for integrating condition-based economic modelling with digital asset management systems in aviation). First published online 9 June 2026