North Atlantic Tracks (NATs) are daily high altitude transatlantic routes between western Europe and the eastern coast of North-America, which provide consistent separation between aircraft. Westward tracks are named incrementally from the beginning of the alphabet (A,B,C...), with the northernmost tracks named first. Similarly, eastward tracks are named incrementally from the end of the alphabet (Z,Y,X...), with the southernmost tracks named first. Daily updates for each direction allow for routing around weather systems and tracking of favourable tailwinds to improve efficiency.

The map below shows the current valid NATs and the upcoming published NATs, along with the permissible flight levels in each direction.
Track Valid From Valid To Route East Levels West Levels
A 04 Dec 1130 UTC 04 Dec 1900 UTC SOMAX 49/20 46/30 45/40 43/50 JEBBY CARAC 350 370 390
A 05 Dec 1130 UTC 05 Dec 1900 UTC ERAKA 60/20 61/30 61/40 60/50 URTAK 350 370 390
Z 04 Dec 0100 UTC 04 Dec 0800 UTC ALLRY 51/50 53/40 55/30 55/20 RESNO NETKI 320 340 360 380 400
Z 05 Dec 0100 UTC 05 Dec 0800 UTC RIKAL 53/50 56/40 57/30 56/20 RESNO NETKI 320 340 360 380 400
Warning: Do not use this data for real-world aviation or navigation. No guarantee of current accuracy is given.