# NFT-Based Framework for Digital Twin Management in Aviation Component Lifecycle Tracking
## 3 Results
### The Workflow for Maintenance Records Using NTT-Based Technology  
The workflow for maintenance records using an NFT-based system presents a technologically advanced approach to aircraft maintenance documentation and tracking (Figure 5). This process integrates regulatory compliance, detailed inspections, and quality checks, while using NFTs to ensure secure, immutable record-keeping throughout the maintenance lifecycle.  
The process begins when maintenance is scheduled for an aircraft or its components. At this point, a new NFT is created to represent this specific maintenance event. This digital token will serve as a unique, blockchain-based record of all activities and outcomes related to this maintenance session.  
The first operational step is the pre-maintenance inspection. During this phase, technicians thoroughly examine the aircraft or component to assess its condition and identify any issues that need addressing. The findings from this inspection are recorded, and the NFT is updated accordingly, creating a baseline for the maintenance work to follow.  
As the workflow progresses to the maintenance performed stage, all actions, replacements, and repairs are meticulously documented. Each step of the maintenance process is recorded, and the NFT is continually updated to reflect these activities. This ensures a comprehensive, real-time record of all work carried out.  
Following the completion of maintenance tasks, a post-maintenance inspection is conducted. This crucial step verifies that all required work has been performed correctly, and that the aircraft or component meets all necessary standards. The results of this inspection are also recorded, with the NFT being updated to reflect the outcomes.  
A quality check follows the post-maintenance inspection. This serves as a final verification that all work meets the required quality standards. If the maintenance passes this check, the process moves to sign-off and approval. If issues are identified, the workflow directs to an address issues stage, where any problems are rectified before the maintenance can be approved.  
Throughout these stages, there is a continuous emphasis on regulatory compliance. The system verifies compliance at multiple points in the process, ensuring that all maintenance activities adhere to relevant aviation regulations and standards.  
Figure 5: Flowchart of the workflow for maintenance records.  
Once all checks are passed and issues (if any) are addressed, the maintenance undergoes a final sign-off and approval. This step typically involves authorized personnel reviewing all the documented work and inspections before giving final approval. The NFT is updated to reflect this approval, creating an indelible record of the maintenance event's successful completion.  
After approval, the aircraft or component returns to service. The NFT is updated once more to indicate this change in status. Following this, the aircraft records are updated to reflect the completed maintenance. This step ensures that the broader aircraft documentation is in sync with the specific maintenance event.  
The final stages involve linking the maintenance NFT with other relevant NFTs. This creates a network of interconnected digital records, allowing for comprehensive tracking of the aircraft's maintenance history and the status of its various parts.