At the end of nearly each lesson, when you got your rating and the screen will then change to close your lesson the main executable crahes and the program is restarted.
I tested that on two different systems with newest Windows 10 64 Bit, newest BIOS, newest drivers for main board graphics etc.
Systems are (both with no overeclocking):
1. ASUS Z270-A, 16 GB, Intel i5 7600, ASUS ROG Strix 1070 OC, 8 GB, Samsung M.2 SSD
2. ASUS Prime X370 Pro, 16 GB, Ryzen 5 1600X, ASUS ROG Strix 1070 OC, 8 GB, Samsung M.2 SSD
Checked following settings:
- Starting game normal/as Admin
- Using Full Screen/Window Mode
- Using all graphics qualities from high to low
- Using Windows w/wo gaming mode
- all possible solutions from forum
Normal flight is possible without any erros. External Hardware is only Microsoft Sidewinder Precision Pro, no TrackIR etc.
I found some themes depending this error, checked all possible forum hints, but no success.
Because this occurs on two completely different processor systems, i assume a software error.
Even if thats an error which is difficult to evaluate, i can reproduce it nearly always, only sometimes (<5%) one lesson works and the crash occurs after second lesson.
Maybe, some code refactoring in this section where lesson ends, may solve that, even if no one knows why 
Regards
Roger
