hmmm… the error combination " 0xc0000409 & ucrtbase.dll " is normaly the missing lang pack “US”. The FAQ recommend a re-install: https://flightsimulator.zendesk.com/hc/en-us/articles/360015893879-Crashing-CTDs-issues
But here is a thread where it was seemingly caused by security software like Bull Guard ( which often cause trouble ):