The North Atlantic Organised Track System (NAT OTS) Explained
The North Atlantic links Europe and North America and carries a very large volume of traffic. Because so many flights cross at similar times, a system of organised tracks is published to keep the traffic flowing safely and efficiently.
What the OTS is
The Organised Track System (OTS) is a set of tracks published to suit the weather and the traffic. It sits within the NAT high level airspace, predominantly in the Gander and Shanwick oceanic control areas. Flights may also plan random routes outside the OTS.
How it is built
The OTS planners coordinate with the adjacent oceanic area control centres and with domestic ATC agencies to make sure the proposed system works. Once agreed, it is promulgated through the NAT Track Message, which gives the coordinates of each track and the flight levels expected on each. There are separate westbound and eastbound messages, and the hours each one is valid are stated in its header. See the track message guide.
Lateral spacing
According to ICAO North Atlantic Operations Bulletin 2024-001, OTS tracks are designed with a minimum of 42.6 km (23 NM) lateral spacing, through whole and half degrees of latitude, between FL340 and FL400 inclusive, except in the New York oceanic area. According to OPSGROUP's summary of NAT Doc 007, flying on the half-degree-spaced tracks needs RNP 4 approval and the required communication and surveillance performance (PBCS), plus a State approval.
Where it fits
The OTS lies inside the NAT High Level Airspace, which has its own approval requirements. They are covered in the NAT HLA guide. Procedures in the region change from time to time, so always check the current edition of the North Atlantic Operations and Airspace Manual (NAT Doc 007) and the State AIPs. Information here was checked in October 2026.
FAQ
Do all flights have to use the OTS?
No. Flights can plan random routes within the allowed airspace, as long as they meet the requirements and obtain an oceanic clearance.
Who publishes the OTS?
The tracks are agreed by the OTS planners at the oceanic centres and published in the NAT Track Message.
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For training and reference only. Check official sources before any real flight.