NAT Track vs IFR cruising altitudes

Just a quick question. Looking at the NAT Track Z westbound-eastbound track for today, the cruising altitudes for the track are shown in even intervals, however on my simbrief flight plan my NAT track altitude is FL370. Technically this is correct for the IFR cruising altitudes restrictions based on heading but wondered if anyone could shed a light on whether you instead fly even FL’s for the NAT track.

NAT track Z, Y, X, etc will only be eastbound tracks so odd FL should be used.

However NAT track A, B, C, etc. are westbound tracks and even FL should be used.

Check out this tutorial for more info on Oceanic Tracks: Oceanic Flying Tutorial

Hope that helps

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That’s not true from what I’m aware…

Whilst flying on a Track, you ignore the semi-circular rules for an IFR cruise. Instead, you follow the published altitudes (can be a mix of even and odd for one direction) for that Track.


That’s what I thought but just found it odd that Simbrief (and some other sources) said the Eastbound tracks are even…

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Thats because on the NAT Tracks in both directions you can cruise at any altitude between FL320 and FL410.


The semicircular rule is applied everywhere to begin with. You are techinally supposed to use the published altitudes.

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