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 table 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

Pacific Organised Track System (PACOTS) tracks are daily high altitude pacific routes between eastern Asia and the western coast of North-America. Eastward tracks are named numerically (1,2,3...). Similarly, westward tracks are named incrementally from the beginning of the alphabet (A,B,C...). Daily updates for each direction allow for routing around weather systems and tracking of favourable tailwinds to improve efficiency. The table below shows the current valid PACOTS tracks and the upcoming published PACOTS tracks.

Track	Valid From	Valid To	Route