16-08-2021, 03:29 PM
I did a search regarding the C441 and FS9. I had forgotten that I had the 441 years ago, but never had the overspeed issue. It doesn't appear others had this problem either. At any rate, you can adjust the max indicated airspeed or disable the overspeed penalty when using the 441. Apparently that is the best advice I can give at the moment.
See FsPassengers Frequently Asked Questions: FAQ