Decode of NAT Track Message

[extricate]

Hi there,


I'm curious about North Atlantic Ops and was reading up on the NAT Track Message. Can anyone help with this decode? TZA179 082009
FF BIRDZQZZ BIKFYXYX
082009 EGGXZOZX
(NAT-1/3 TRACKS FLS 310/390 INCLUSIVE
APR 09/1130Z TO APR 09/1900Z
PART ONE OF THREE PARTS-
A ERAKA 60/20 62/30 63/40 63/50 MAXAR
EAST LVLS NIL
WEST LVLS 310 320 330 350 360
EUR RTS WEST ETSOM
NAR -
What does those in bold refer to?

Thank you

[Sepp]

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.

[CI300]

If your interested, theres a bit more info on the formating of AFTN;

https://en.wikipedia.org/wiki/Aerona...cation_Network