TZA179 is the transmission ID. FF means this is a flight safety message. The eight letter bits are airfields/centres and their types: BIKF (Keflavik) is a military airfield (YXY) and the trailing X just completes the format. EGGX is Shanwick and it is an Oceanic Centre (ZOZ). Similarly, BIRD is Reykyavik FIR (ZQZ). I suspect the trailing Z should be an X? ZQZX makes sense. The numbers are a date/time group.
Last edited by Sepp; 14th Oct 2021 at 14:25.