So, it seems to be an issue related to XEnviro at this time. I disabled that plugin (even after updating it) and with it active, it crashes at KSDC each time. Even just sitting on the runway. There's a momentary stutter, followed by normal operation for about 2 seconds, then a freeze, then a crash. This starts after about 15 seconds after first render. It seems to correlate with XEnviro changing the weather. I see the Altimeter moving just before the crash.
I tried in the stock cessna 172 after your suggestion, and then started with all plugins disabled, adding one at a time and trying different combinations until XEnviro seemed isolated.
Any ideas on troubleshooting this?
UPDATE: Just crashed with XEnviro disabled. Hmm.