Maybe you are getting zapped by cern (I don't have a clue if the ring is under that bit)
There are some pretty hefty magnetic fields coming off some of thier gear and maybe enough to throw a comparitor error into your system if it has such a thing.
My home airport is smack on top of the CERN accelerator ring but it doesn't seem to affect planes big or small - they certainly don't need to turn it off for CAT3 approaches
