Check 6, no offence meant... However, whenever I operated a GPS near Catania (or south-east Sicily for that matter) it always goes berserk. I saw this on two totally distinct aircraft types. Also suffered degradation when using a GPS on a boat in that same area. I thought it had something to do with the big prohibited area around Capo Passerro (sout-east tip of Sicily) but this may be going into chemtrails/x-files territory
