I'm not sure what I did wrong here, maybe I missed something. I installed the latest AIRAC cycle. Now, the FMC shows a particular frequency for a runway, but when I try to tune the radio for the runway and the ILS doesn't tune. I later found out that the radio freq in the map for FS9 doesn't match the freq in the FMC. Is that significant? When I tune the freq. in the map, the ILS does tune.Maybe I'm just being silly :)

Yep, installing a new airac will do that - the airac will be current, but not always what is in fs9 or fsx.Three ways round it:-1.Alter the airac file to suit the frequencies in fs9 or fsx.2.Alter the afcad file to alter the frequencies to suit the airac.3.Tune the frequency found on the fs9 or fsx map.I believe the frequencies were correct in around 2006 but have moved on since then. LIRF being wrong for one.There are a couple of utilites out there to alter the afcads.John Ellison

Thanks for that John, I thought I was missing something as I have been away from the sim for more than two years. So what are these utilities to alter the afcad files? I'm assuming AFCAD is whatever the maps are in.

Just put afcad in google.co.uk and it's the first item on there. For fsx it's more complex lol - you'd need something like airport design editor or fsxplanner.John Ellison