I can cause this crash by using the FSX menu to "restart couatl" - it then causes the error below first, followed by FSX crashing with a bglmanx.dll error
This has been discussed many times on the forum already. The "Restart Couatl" function currently doesn't work on Steam. We finally found what caused it, and we'll release the fix with the next Couatl update.
It's not yet out, because it's a fairly major update, with basically everything related to it updated, which will result in way better compatibility with Steam ( it will use the VC++ 2013 runtimes ), but with also lots of speed improvements due to a new Python language interpreter, new support libraries, updated GUI, etc. , so we need to do a bit more testing.