I've been flying in a non mountainous region with fixed weather (fair) and while cruising along with autopilot egaged, I will hit some fairly severe turbulance for a few seconds and when it smooths out, I have an incredible climb rate and the autopilot has to pitch the nose down 20 degrees to keep a constant altitude. After a few minutes, I hit a few seconds of severe turbulance again and then I'm suddenly diving and the autopilot pitches up to compensate.This isn't an autopilot problem, it's reacting to some external influcence.Is anyone else seeing this?Is this how they modeled thermals or something?Thanks.

"Is anyone else seeing this?"It hits me once in while too. I don't know whether it is related to turbulence or thermals. There is an option in the settings menu to turn turbulence off.Jozef K. http://homepages.onsnet.nu/~jkusters/signature.jpg

Thanks. Glad(?) to see it is not just me. I will see what I can do about it... Even if it is a thermal, I wonder if they are that frequent and of such magnitude for a C172 in real life.

You can be a long way from mountainous terrain and still be affected by wave lift generated from hills, as it propogates away from the source in waves like a ripple from a pond, and can do this for many miles. Even simple thermal lift can give incredible climb rates.I can remember spotting a house on fire way down below me once, I circled over the thin smoke plume from the fire up at about two thousand feet, and was very soon up another two thousand feet, while circling. I had a bird in formation with me doing the same thing (got some great views of the very subtle changes it made to its wing shape to steer itsef). While I was doing this there were all sorts of things floating up past the cockpit window (crisp packets, carrier bags, pages from newspapers etc) despite the fact that I was going up like a rocket.The rate of climb in the 'up' part of these phenomenon is fairly spectacular in a small aircraft, and pretty severe even in a large one. When you get in the 'down' part it can easily overwhelm your ability to climb and has been the cause of several accidents over the years. It has even been known to flip airliners inverted and caused one or two of them to break up in mid air in fact, one well documented case being a B.O.A.C. Boeing 707 which the pilot took close to mount Fujiyama in Japan to give the passengers a view of it in 1966, resulting in the aircraft coming apart in mid air owing to the turbulence it encountered, tragically killing everyone on board.There is speculation that several air accidents attributed to other causes may have in fact been caused, or exacerbated by this phenomenon, most notably the crash of a United Airlines Boeing 737 near Colorado Springs in 1991 which rolled inverted while on finals for Colorado. For a time, many Boeing 737s were grounded while this was investigated. While this accident is believed to have been caused by an uncommanded rudder deflection and indeed this was the finding of the NTSB investigation, some have suggested other factors might have been in there too.What is not in doubt however, is that rough air can and has been extremely dangerous to many aircraft, with wake turbulence from large aircraft having been found to be capable of putting aircraft out of control for periods of up to fifteen minutes after the initial aircraft has passed by. The Boeing 757 is extremely controversial in this respect, as it has been found that despite its size and weight meaning it does not require the suffix 'heavy' in ATC calls, it can cause a great deal of wake turbulence, and the 'heavy' addition to ATC callsigns is something that ATC use as a factor when deciding aircraft separation limits.If there have been random air pockets and other phenomenon placed into FSX, it is certainly something which is definitely not at odds with the real world; I suspect a lot of desktop pilots are discovering what many real-world pilots already know - that the sky is not as benign as it often appears.Of course it could be a bug too, but that kind of thing can and does happen in real life. I suggest you do what glider pilots do: slow down in the rising air and take advantage of it, and stick the nose down and speed up to get out of the falling air as soon as you can.

Yep, been there, done that :D I mainly fly out of KSEA since that was the default flight in FS9 and I know that area best.Flying out of KSEA in the C172 toward downtown Seattle with "fair" weather and time around noon, I often get just what you're talking about. As I approach downtown Seattle at around 1.5-2k, I'll often get moderate to severe turbulence. Pretty cool actually ;)Then as I get in the vicinity of the skyscrapers, I'm getting ungodly updrafts and the VSI freaks out, I've got throttle at idle and 10-20 degrees nose-down just to try to keep from climbing! And I don't fly with autopilot...After I get past the downtown area, the updrafts and turbulence ease off. I can only assume it's the wind whipping around the tall buildings, and the heat rising off the hot pavement?Doesn't always happen, did that same flight last night and it was pretty sedate! Little bit of turbulence, little bit of updraft but nothing major. Gotta admit, I kinda like it, keeps things "interesting" ;)

Updrafts typically have an area of turbulence before you enter the actual draft, in which the air will smooth out and lift will begin. I don't see updrafts too incredibly often, but when I do you can pretty easily identify them.