Well, I don't know if anyone else has (had) this problem or if it has be posted elsewhere before but I have ALWAYS had a problem with my CS 767. After a while in flight and the autopilot is on the aircraft will for no apparent reason go into an uncontrollable flat spin down to the ground and crash, this is the only aircraft that does this and I have updated it to the latest patch. Unfortunately due to this event often happening I get discouraged and have no interest in flying this aircraft anymore, thus I have put the aircraft into retirement. Has anyone experienced this with the 767? (going into a flat spin)

Oh dear, what a shame. From what you say there is nothing wrong with your aircraft, the problem I am sorry to say is you. You need to learn how to fly it and some of the basic principles of aeronautics. Very simply a flat spin is caused by lack of lift. In a fixed wing aircraft that is caused by insufficient forward motion - not enough wind under your wings.
Read a bit more about the aircraft and how to fly it. It is not one that anybody can get in, press a button and wander off into the blue yonder.
Take some time to learn a bit more - the rewards are worth it.

I totally agree, I had that issue at first, then I went a learned thru trial and error! Keep practicing you will get it. The only problem I have withit is now is with the autoland! It's quite simple to get it up once you figure it out, but landing,lol is a whole other monster!

@silverbeard,  Sir you are not talking to someone who is new to flying an aircraft. I have been flying since 1984 and have a few thousands of hours under my belt,I know all about lift and stalling a aircraft. Perhaps I did not correctly explain what has been happening with my aircraft, I am at level flight in the sim,(have been for a while) everything is as it should be, flight altitude,airspeed,engine parameters showing normal conditions, etc. , I'm just sitting there in front of my screen (I do not have my hands on the joy stick) and "bam" it's starts to quickly and instantly spin round and round, then nose is all over the place tilting up then down, then round and round, impossible to control at that point and just crashes into the ground. It only does it with this model aircraft and it is the only one from CS I have installed on my computer. I do have many add-on's, planes,scenery,weather, FS Passengers, etc., and was thinking perhaps one of my add-ons is creating some sort of a conflict.

I have a decent computer and have all my drivers up to date, as mentioned I have a lot of add-ons  so I am starting to think at this point that one of them is creating a conflict, I will have to look into this matter further.