NAT High Level Airspace (HLA) Requirements Explained
Much of the North Atlantic is designated as NAT High Level Airspace, or NAT HLA. It has stricter requirements than the rest of the region, because it is so busy.
NAT Region and NAT HLA
The NAT Region is virtually all of the non-domestic airspace over the Atlantic. The NAT HLA lies inside it, between flight levels 285 and 420 inclusive. The organised track system sits within it.
What it takes to enter
- State approval. The State of Registry or the State of the Operator approves aircraft that meet the NAT HLA standards, and confirms that suitable crew procedures and training are in place.
- Navigation. Operators need RNP 4 or RNP 10 capability, with two independent long-range navigation systems.
- RVSM. Reduced vertical separation applies from FL290 to FL410 throughout the NAT HLA, so aircraft need RVSM approval. Aircraft without it are cleared above or below RVSM airspace.
- Datalink. The North Atlantic datalink mandate means aircraft need CPDLC and ADS-C to operate between FL290 and FL410 in the NAT Region, with some exempt areas, such as airspace north of 80 degrees north and the New York oceanic area.
- Transponder. Transponders should be on at all times in the region and set to code 2000, unless told otherwise by ATC.
If an aircraft does not qualify
It can still cross the Atlantic, but must fly above FL420 or below FL285.
Half-spaced PBCS tracks
Flying on the half-degree PBCS tracks needs RNP 4 approval and the required communication and surveillance performance, along with a State approval.
These requirements are summarised from SKYbrary and from OPSGROUP's summary of NAT Doc 007, checked in October 2026. The current NAT Doc 007 and your State's rules decide what applies to your flight.
FAQ
What is the difference between the NAT Region and the NAT HLA?
The region is almost all non-domestic airspace over the Atlantic. The HLA is the busiest part of it, between FL285 and FL420, and needs approval to enter.
Is RVSM required in the NAT HLA?
Yes. RVSM applies between FL290 and FL410, so aircraft need to be RVSM approved to fly in the NAT HLA.
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For training and reference only. Check official sources before any real flight.