I have just completed a flight. A discovery flight all around Sydney Australia, landing at Kingsford Smith Int, taxi round the airport then taking-off, flying low around Sydney Harbour about 350ft and then up to 5000ft . Flight time over 1 hour, I don’t think the taxi time at airport was included. No problems, in 4K and ultra settings. Very smooth flight. I will need more test flights, but it is almost certain BitDefender AV was the cause of the CTDs. I just disabled a few BD modules, and I can easily re-enable them for other PC stuff. CTD’s at long last are fixed. Very Happy. I will get back to this, after few more tests, and let you know what BD say about this, to improve its exceptions to FS2020. Thank you all.