Reliability Risk Analysis of Non-Conforming Components in Turbofan Engines: A Complexity-Integrated Fault Tree Approach

Ghasemi, Mohammad Javad; Esmaeili Yengejeh, Sina; Rafie, Mohamad Hossein; Hosseini Moghaddam, S. M. Hossein; Navaei, Alireza; Fakhr Tabatabaei, Abbas; Afshar, Ahmad; Farsi, Mohammad Ali

doi:10.22034/IJRRS.2026.9.1.9

Reliability Risk Analysis of Non-Conforming Components in Turbofan Engines: A Complexity-Integrated Fault Tree Approach

Document Type : Industrial Case Study

Authors

Mohammad Javad Ghasemi ¹

Sina Esmaeili Yengejeh ²

Mohamad Hossein Rafie ³

S. M. Hossein Hosseini Moghaddam ¹

Alireza Navaei ¹

Abbas Fakhr Tabatabaei ¹

Ahmad Afshar ⁴

Mohammad Ali Farsi ⁵

¹ Mapna Aero Engineering Company (MAPNA Group), Tehran, Iran

² Department of Aerospace Engineering, Amirkabir University of Technology, Tehran, Iran

³ School of Mechanical Engineering, Iran university of Science and Technology, Tehran, Iran

⁴ Department of Electrical Engineering Control, Amirkabir University of Technology, Tehran, Iran

⁵ Aerospace research Institute, Ministry of Science, Research and Technology, Tehran, Iran

10.22034/IJRRS.2026.9.1.9

Abstract

In this paper, a process model is developed to assess the effects of using NCR (Non-Conforming Replacement) components versus the Original Equipment Manufacturer (OEM) components in terms of safety and reliability. This process links complexity management to system reliability by gradually updating the system model to incorporate each component’s interactions and feedback loops. It employs an incremental, evolution-based methodology to refine system reliability predictions, using complexity metrics to assess the impact of each component. Our approach is experimental, using data relevant to a type of turbofan engine. Rather than relying on complex mathematical models that may have limited relevance for the application environment, we tailor our approach to aviation standards and complexity management algorithm development experiments to identify key defect-related predictors of quality. This process has been tested on critical components of turbofan engines, with all aspects of safety and reliability in mind. NCR components, which are approved by the design office, are assessed for their risk, and their effects on the overall reliability of the engine are calculated. The process begins with a risk analysis of each component, followed by the extraction of interactions and feedback loops using a complexity management algorithm. Finally, the reduction in engine reliability is calculated using a fault tree analysis (FTA), considering the complexity factor. The results show that complexity metrics are strong predictors of defects and test efficiency in this evolutionary process. At the end of the process, reliability changes for each component are calculated, providing a clear measure of its impact on the system. This allows comparison between components and supports informed decisions regarding the use of NCR components, even if approved by the design office.

Keywords

Safety

Complexity

Turbofan

Fault tree analysis

Reliability

Subjects

Reliability Engineering

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