From the Wiki;
FsFlight is the graphical tracklog viewer of the FS solution. It will display the loaded task, and one or more tracklogs from the task.
It can be started from FsComp (under the Tools menu).
In the current version it is not very fancy, but provides all you need to verify a tracklog visually.
* Select pilots from list, active pilot tracklog is black, prevoius selected pilot is red.
* Point mouse at tracklog to get information about nearest tracklog point from active and previous active log.
* Left click to center view
* Left click and drag to zoom in
* Right click to zoom out
* Right click and drag to measure distance