Open Part 1 using a tool like WinRAR or 7-Zip . The software will automatically bridge the data across the other segments, including Part 13.
This indicates that you need all preceding parts (part01 through part12) and any subsequent parts in the same folder to successfully extract the contents. How to Use the File GF191022-ULOTC-FLT.part13.rar
Multi-part RAR files cannot be opened individually. Ensure you have every "part" file in the set (e.g., .part01.rar , .part02.rar , etc.) saved in the same directory. Open Part 1 using a tool like WinRAR or 7-Zip