Just to be clear, the KIAHKDFW.FLTPLAN file is used by iFly. I included the default PLN file as reference, but it is not causing an issue.
Included with the addon are a bunch of PDF's. On of them is called FlightPlan Introduction and describes the iFly .FLTPLAN format. Do you have that PDF? I can send it to you, if you like.
I've compared the FLTPLAN file with the notes in the PDF and there are some issues I think may be interesting to look at.
For example: "Note: It is highly recommended to leave ‘-1;’ for the lines #11 and #16, leave ‘;’ for the lines between #5 and #10, #12 and #15 in order to avoid potential unnecessary conflict.".
As you can see in the attached file, line 11 is -1, but 16 isn't. And 5-10 and 12-15 are empty (,), instead of containing ; (;,). I'll change those lines tomorrow and see if it still crashes the sim.
The actual waypoint lines are a bit more challenging.
