This is due to the battery going dead in FS2002 and is a known FS (not A320) bug as such. All you need to do to fix this is to set FSUIPC to "Extend Battery life". To do this, start FS2002. On the menu bar click on "Modules", Click on FSUIPC, click on the "technical" tab, click to ON the option "Extend Battery life", Click "OK" and go flying.