Ok, I´ve been having this supposed "problem" for a while now, and even after doing lots of testing, I´m still unable to track its cause. I run FS9.1 on Windows 7, a clean install on its own directory outside Program Files and running as admin, following many recommendations. FSUIPC settings are standard. On any flight, over any region of the world and through any weather conditions (including, most notably, clear weather with absolutely no winds, as set via FS and FSUIPC) the MD-11 will constantly deviate slightly from the flight plan track (generally 0.1nm to the left or right) and then produce a noticeable turn of about 5º bank angle to reintercept. It will then fly straight and level for a couple of minutes and do everything again. As I said, this happens at about every 5 minutes interval, during the whole flight as long as NAV is engaged. Again, it happens even with zero wind conditions. I´ve logged lots of MD-11 hours on an old Windows XP system and never noticed this annoying behaviour. From my testings, I concluded that it´s apparently not influenced by weather (as it happens in clear weather), scenery (clean FS installation), FS startup (default flight is a C182 with engines off), navdata (many AIRAC cycles have been tested), registry (FS Registry Repair was tested), operating system and hardware (same behavior on two different computers with W7 64 and Vista 32, although it ran fine on XP as long as I can remember; same behaviour with or without a joystick).I think I ran out of options on how to determine the cause, but I´m still reluctant to believe it´s normal behaviour of the plane. I´ve attached a picture of the supposed issue, highlighting the deviation from the track and the abscense of winds. Any suggestions will be appreciated.Sorry for the long post, but that´s just because I really love this plane.Thanks!Marcelo Torres

Be glad it's not the Sperry SP-50 Mk IV. :(

I would say you most likely hit the nail on the head about Windows XP. Personally, I think the FS9 version of the MD-11 coupled with XP is the most stable combination. I would think it a windows 7 "thing", but I will defer to someone else who actually has windows 7.

hi,i would try as followed:remove fsuipc from the modules folder for a testflight and start a new flight with "clear sky" in FSone time auto allignedone time manual allignedany differences?

hi,i would try as followed:remove fsuipc from the modules folder for a testflight and start a new flight with "clear sky" in FSone time auto allignedone time manual allignedany differences?

Paul, thanks for your advice but the plane doesn´t work properly without FSUIPC... panel is completely black and virtual cockpit corrupted

Check your magvar.bmp (I think it is named) in FS9 that it is original and not modified. Just a guess. Sure hope you post your finding if/when found.

I would say you most likely hit the nail on the head about Windows XP. Personally, I think the FS9 version of the MD-11 coupled with XP is the most stable combination. I would think it a windows 7 "thing", but I will defer to someone else who actually has windows 7.

Bill,I am using the MD11 in W7 64 and no issues, in fact , I think it is better. The reason I say that, is todays modern hardware needs W7 to run at it's optimuim (64 not 32bit) Win XP in it's day was the best M$ ever produced, but sometimes you have to bite the bullet and go with the OS that will run your hardware at a level thatt FSX (9) likes. A few months ago I would not have said that.Only today, I did a flight in the MD from KDFW to KJFK, and did everything I expected it to do, and more. So if you are running older systems XP is fine, newer hardware, definatley W7 64bit, no question.CheersJulian Evans