Seems like the XnConvert program supports the Flexible Image Transport System format (*.fts) and thus can be used to export it to PDF format.
Convert Flexible Image Transport System format to Adobe Portable document format.
We found 2 software records in the database related to .fts to .pdf file format conversion.
Multiplatform software - convert fts to pdf on any platform
Cross-platform batch image transcoder compatible with 500 picture image formats
Convert from fts file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned fts to pdf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A popular utility for viewing and converting graphic files