# NFT-Based Framework for Digital Twin Management in Aviation Component Lifecycle Tracking
## 3 Results
### The Workflow for Certification and Compliance Using NFT-Based Technology  
The workflow for certification and compliance using an NFT-based system outlines a comprehensive process that ensures that rigorous standards are met while maintaining a secure and immutable record of all stages (Figure 6) to create a transparent, traceable, and tamper-resistant documentation trail throughout the certification lifecycle.  
The process begins with an application for certification. At this point, a unique NFT is created to represent the entire certification journey. This digital token will serve as the primary record, updated at each stage to reflect the current status and history of the certification process.  
Following the application, an initial assessment is conducted. The results of this assessment are recorded by updating the NFT, creating the first substantial entry in the certification record. This stage culminates in a critical decision point: determining whether the subject meets the necessary requirements.  
If the requirements are not met, the process moves to address deficiencies. Here, any issues identified during the initial assessment are tackled. The NFT is updated to reflect these corrective actions, maintaining a clear record of the improvements made. Once deficiencies are addressed, the process loops back to the initial assessment stage for re-evaluation.  
When the requirements are met, the process advances to evaluation and testing. This more intensive phase involves thorough examinations and practical tests to ensure full compliance with certification standards. The NFT is updated with detailed results of these evaluations, providing a comprehensive record of performance across various criteria.  
Another decision point follows, determining whether the subject passed the evaluation and testing phases. If not, additional training or corrections are required. This stage allows for targeted improvements based on specific shortcomings identified during evaluation. The NFT is updated to reflect these additional measures, ensuring a complete record of all steps taken towards certification.  
Upon successful completion of evaluation and testing, the certification is issued. This milestone is recorded in the NFT, marking a significant transition in the subject's status. The certification then becomes active, with the NFT serving as the authoritative digital representation of this certified status.  
During the period of active certification, two parallel processes occur:  
1. Ongoing compliance monitoring, which involves regular checks and updates to ensure continued adherence to standards. The NFT is periodically updated with compliance data, creating a real-time record of the subject's status.
2. Tracking of certification expiration, during which the system monitors the validity period of the certification. As expiration approaches, it triggers the recertification process, ensuring timely renewal of credentials.  
The final decision point in the workflow asks whether compliance is maintained. If yes, the certification remains active, and the cycle of monitoring and potential recertification continues. If compliance falters, the process may lead to suspension or revocation of the certification. This severe action would be recorded in the NFT, providing an indelible record of the certification's termination and the reasons behind it.  
Figure 6: Flowchart of the workflow for certification and compliance.