One of my ctd,s happened after a 6hr flight and landing at 4am sim time.
The question posed by the original poster was quite specific about a crash happening at a precise time. To that, I replied.
A memory leak is more easily created by an airplane, which includes lot of executable code in all gauges.
The fact that doesn't happen in other sceneries, doens't mean much. If the culprit is the airplane you are flying, it might very well be that, if you are on the *borderline* between being still able to fly even with a memory leak, it would be just barely enough for a scenery to take just a little bit more of memory, WITHOUT having a memory leak by itself, but just to be enough for to allow for the memory leak you already had, to go to the other side of the borderline that would make it crash.
Example: if you have a memory leak caused by an airplane that start (for example) with 800MB and consumes 1.95 GB in 6 hours, over a certain scenery, it will still let you land at your destination. If you use a scenery that takes those 50MB extra (without that necessarily means is leaking), you'll end the memory, have the sim crashing, and think it's the scenery.