Hope i am right here...
I had this Problem twice today. I was flying from LOWL to EDDF and the game crashed when i had done around half the flight.
I did not do anything. I was cruising on Autopilot at 1x speed at 30000ft.
I use realistic Weather and i was on the MP server
I use version 2019.1.1 on Windows 10 Pro
My PC has definitly enough Power for the sim (i7 4770, 16GB RAM, GTX 1070)