If you are developing content please make sure you turn on Content Error Reporting.
When using the setting, Prepar3D will report common problems that should be fixed before releasing your product.Content Error reporting can be turned on in the General -> Simulation Settings Screen or by setting ContentErrorReporting=1 in Prepar3D.cfg's [MAIN] section.
If this value is set to 1, errors related to content will be logged to the following file:
%USERPROFILE%\Documents\Prepar3D v4 Files\ContentErrorLog.txt
Regards and thanks!