Ute, How old is your joystick. I had a similar problem last month. I had a Thrustmaster joystick I bought in 95, worked fine for everything, then i noticed that with no input from me everything I flew just sort of drifted to the left and I was constantly correcting my heading, which was a pain especially on bombing runs. I recalibrated several times and used the trim keys but no help. Finally I broke down and bought a new Thrustmaster Afterburner USB Joystick/Trottle/Rudder control $59, and works great. If your joystick is fairly new then try cleaning it and/or uninstall the drivers and the joystick and reinstall and see it that clears it up.