North Atlantic High Level Airspace (NAT HLA) - Civil Aviation Safety Alert (CASA) No. 2019-10


All pilots, flight dispatchers, air operators and private operators planning to conduct flight operations within the North Atlantic High Level Airspace (NAT HLA) including areas designated as Blue Spruce route.

File Classification No. : Z 5000-35
RDIMS No. : 15890744
Document No. : CASA 2019-10
Issue No. : 01
Effective Date: 2020-01-10


The purpose of this Civil Aviation Safety Alert (CASA) is to alert all pilots, flight dispatchers, air operators and private operators of the following changes:

  1. the final phase of the International Civil Aviation Organization (ICAO) Data Link Mandate (DLM) including the expanded vertical and horizontal boundaries from Flight Level (FL) 290 to 410 will commence January 30th, 2020.
  2. the changes to the navigational performance required for a North Atlantic High Level Airspace Minimum Navigation Performance Specifications (NAT HLA MNPS) approval will also become effective on January 30, 2020.

It is implicit in the concept of the NAT High Level Airspace (HLA) that all flights within the airspace achieve the highest standards of performance for horizontal and vertical navigation accuracy.

This CASA provides operators the necessary information in order to obtain a NAT HLA MNPS SA from their existing NAT MNPS SA.


On February 04, 2016 the airspace previously designated as NAT Minimum Navigation Performance Specification Airspace (MNPSA) was re-designated as North Atlantic High Level Airspace (NAT HLA).


From January 1, 2015 onwards new NAT MNPS approvals have included a requirement that aircraft be RNP 4 or RNAV 10 certified.

On February 07, 2017, the NAT Data Link Mandate (NAT DLM) airspace expanded to encompass FL350 to FL390 inclusive throughout the ICAO North Atlantic (NAT) Region.

On 30 January, 2020 NAT DLM airspace will expand to include FL290-FL410.

NAT MNPS approvals issued prior to January 1, 2015 and/or based on the previous MNPS approval will not be valid beyond January 30, 2020.

The performance and equipment requirements are as follows:


  • NAT HLA MNPS (Specific Approval)
    • RNP 4 or RNP 10
  • RVSM (Specific Approval)



Performance Based Communication Surveillance (PBCS) Specific Approval is required to operate on the Organized Track System (OTS) within the NAT HLA airspace.

Operators without ADS-C and CPDLC will be restricted to the area designated as Blue Spruce route FL 290 to FL 410 providing the aircraft is equipped with ADS-B.

Aircraft operators are encouraged to review the ICAO North Atlantic Operations and Airspace Manual Doc 007 and to identify special emphasis items.

Although all possible contingencies cannot be covered, the procedures described in ICAO NAT Doc 007 provides for the more frequent cases.

Recommended action:

Operators are advised to coordinate with their Principal Operating Inspector (POI) in order to obtain an updated NAT HLA MNPS SA from their existing NAT MNPS SA; or to apply for an initial NAT HLA MNPS approval (RNP 4 or RNP 10 required).

Transport Canada reminds all pilots, flight dispatchers, air operators and private operators that they must fully understand and comply with the requirements to operate in the NAT HLA. In particular, pilots and flight dispatchers must have an approved training program with respect to NAT HLA requirements as outlined in the ICAO NAT Doc 007 North Atlantic Operations and Airspace Manual.

Air operators are encouraged to incorporate NAT HLA procedures into their Company Operations Manual (COM), Standard Operating Procedures (SOP).

Link to NAT OPS Bulletin Checklist


  1. FAA OPSPEC/MSPEC/LOA B039 Operations in North Atlantic High Level Airspace (NAT HLA).
  2. ICAO NAT Doc 007 North Atlantic Operations and Airspace Manual.
  3. ICAO Doc 4444 Communication Procedures.
  4. ICAO Doc 7030 NAT Regional Supplementary Procedures.
  5. ICAO Doc 9613 Performance Based Navigation Manual.
  6. AC 700-006 Required Navigation Performance 4 (RNP4) and Required Navigation Performance 10 (RNP 10) Airspace.
  7. AC 700-038 Performance-Based Navigation (PBN) – Enroute.
  8. AC 700-039 Requirements to Obtain Reduced Vertical Separation Minimum (RVSM) Special Authorization.
  9. AC 700-041 Performance-Based Communications and Surveillance.
  10. Nav Canada Aeronautical Information Circular 50/19.


ADS: Automatic Dependent Surveillance

ADS-B: Automatic Dependent Surveillance – Broadcast

ADS-C: Automatic Dependent Surveillance - Contract

CASA: Civil Aviation Safety Alert

CPDLC: Controller Pilot Data Link Communications

DLM: Data Link Mandate

FANS 1/A: Future Air Navigation System 1 or A (Respectively, Boeing and Airbus Proprietary Air-Ground ATC Data Link Communication Systems)

FL: Flight Level

MNPS: Minimum Navigation Performance Specification

MNPSA: Minimum Navigation Performance Specification Airspace

NAT: North Atlantic

NAT HLA: North Atlantic High Level Airspace

OCA: Oceanic Control Area

OTS: Organized Track System

PBCS: Performance Based Communication and Surveillance

RVSM: Reduced Vertical Separation Minimum

SA: Specific Approval

TCAS: Traffic Collision Avoidance System

Contact office:

For more information concerning this issue, contact a Transport Canada Centre; or contact Roger Gravelle, Commercial Flight Standards in Ottawa, by telephone at 613-991-3426, by fax at 613-990-6215 or by e-mail at

Document approved by
Robert Sincennes
Standards branch

The Transport Canada Civil Aviation Safety Alert ( CASA ) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry's efforts to provide a service with the highest possible degree of safety. The information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.