Sept. 4, 2015

Beginning Nov. 12, a trial program intended to increase capacity on optimal flight routings for North Atlantic Tracks (NATs) through portions of the Gander, Shanwick and Reykjavik Oceanic Control Areas goes into effect for properly equipped aircraft.

The reduced lateral separation minimums (RLatSM) Phase 1 trial will reduce lateral separation to half a degree (25 nm) on core tracks of the NAT-organized track system for flight levels 350 to 390 inclusive. The current separation is one degree (60 nm).

Operators do not need to apply to participate in the RLatSM trial. However, Universal Avionics Business Development Manager Carey Miller said, “To operate in this environment, you must be FANS 1/A-equipped [Future Air Navigation System].”

Operators will be eligible to flight plan and fly RLatSM tracks provided the flights are:

  • Authorized required navigation performance 4 (RNP 4)
  • ADS-C (automated dependent surveillance-contact) and CPDLC (controller pilot data link communication) equipped and, where applicable, authorized
  • Operating required communications, navigation and surveillance (CNS) systems

A key element, Miller adds, is “adding these waypoints to the database and using the suggested ICAO NAT OPS naming convention.”

Jeppesen said it would add half-degree grid waypoints in the Gander and Shanwick OCAs beginning in aeronautical information regulation and control (AIRAC) cycle 1510, effective Sept. 17. Half-degree grid waypoints for all other North Atlantic regions will be added on or after AIRAC cycle 1512 (Nov. 12).

Bill Macey, Navtech’s product director for flight planning, said his company would process the daily track message in the NOTAM, automatically incorporating the half-degree tracks into the Navtech Flight Plan system.

Flight crews will also need to follow the new “Hxxyy” naming convention according to the ICAO NAT OPS 2015-003 bulletin. The bulletin cautions: “Half-degree waypoint identifiers in the ARINC 424, paragraph 7.2.5 ‘N-prefix’ format have led to a number of gross navigation errors and lateral deviations.”

Guidance intended to remove the potential for such errors is included in the bulletin, and training is recommended. “To mitigate misinterpretation of waypoint coordinates, operator initial and recurrent training programs and operations manuals must incorporate training and guidance to enable pilots to understand map and flight management computer displays of half-degree and whole-degree waypoints.”

“I think it will be a great program overall; it’s just going to require some education up front,” said Miller.

The goal is to have the entire North Atlantic region operating on performance-based navigation (PBN) and performance-based communication and surveillance (PBCS) by 2020. Once reduced lateral separation over the NAT becomes permanent, business aircraft operators will need to have appropriate PBN/PBCS equipment and letters of authorization or else they will face restrictions in transitioning through this airspace.

Read the full ICAO NAT OPS 2015-003 bulletin.