## 4 Results and Discussion
### Impact on the Engineering Analysis at the Project Phase
It prioritizes the augmented task based on the risk matrix and defines a cost-effective assistance application, as complete augmentation for maintenance tasks might not add value; moreover, it is time-consuming and costly. In summary, augmented reality might reduce error rates in maintenance work and increase safety levels, which might reduce failure rates and consequences to some extent. AR applications can also be integrated to function as reporting applications for maintenance tasks that might provide more complete, accurate, and timely data to be utilized to enhance the quality of data analytics and reinforce future planning tasks. Digital Twin Building Analysis has emerged to determine the capability level and technical specifications of the desired digital twin. The digital twin technology, by itself, emerged from digital models, real-time measurement (IoT), and advanced analytics (cloud computing and simulation modeling). The purpose of the digital twin is the main factor that specifies the level of capability (descriptive, diagnostic, predictive, and prescriptive). The descriptive and diagnostic levels are applied more to reduce the time required to navigate to access diverse data and information. They have the potential to reduce the failure rate as asset conditions are more visualized for operators and can take faster action to prevent failures. However, predictive and prescriptive levels have a greater potential to enhance operating expenses, as they help to use the desired maintenance intervals without the need for corrective maintenance visits. Additive Manufactured Spare Parts Analysis is emerging within spare parts evaluation studies or SPIR studies to allow maintenance engineers to evaluate additive manufactured spare parts options. It determines the location of the printing facility, the lead time, and the expenses. This analysis method is not limited to additive manufacturing; it covers all on-demand manufacturing techniques, e.g., subtractive manufacturing. The main goal behind exploring and engineering on-demand spare parts is to cut down the operating expenses related to inventory holding costs, besides ensuring asset availability under long lead time for spare parts supply. It might appear that on-demand spare parts do not affect failure rates. However, the durability of additive-manufactured spare parts might be questioned and failure rates might be totally different from those of traditional manufactured spare parts. Moreover, the green transition and circular economy are putting more weight on reused or recycled spare parts, which might also have unique failure rates. Model-based maintenance engineering analysis is emerging to transform document-based maintenance engineering to model-based maintenance engineering. Document-based maintenance engineering refers to several maintenance documents (reports, worksheets) that are related to each other and have dependencies in terms of information. The challenge with document-based engineering is the need to manage, communicate, and update all documents if one interdependent document is updated. Therefore, a methodology that makes the dependence between documents more dynamic and parametric is needed. For example, if one document is updated, the dependent documents will be automatically notified of the update. This methodology aims to enhance the maintenance engineering process during the project phase and create a more cost-effective transition (handover process) to the utilization phase. It has no direct impact on failure rates and consequences.