The International Civil Aviation Organization updated the North Atlantic Tracks (NAT) to reflect the elimination of the Blue Spruce routes, which date back to World War II but are now rarely used. According to flight operations information specialist OpsGroup, aircraft with a single long-range navigation system (LRNS) will have to transit the NAT via Gander Oceanic airspace and the Iceland-Greenland Corridor.

Taking effect today, the changes were made through the latest update of NAT Doc 007, the main guidance for operations over the North Atlantic. OpsGroup explained that the Blue Spruce routes, which “have been around since forever,” go between Greenland and Iceland and were designed for aircraft with limited navigation capabilities.

However, the Blue Spruce Routes Project Team decided there weren’t enough ground-based navigation aids to support the routes reliably, few operators with single LRNS rely on them, and the flight distance between Blue Spruce routes and alternative corridors was small. Also part of the reasoning was that the Iceland-Greenland surveillance corridor is a good alternative for aircraft with navigation issues.

These routes were created early in World War II for military aircraft transiting the airspace. The name is a nod to the spruce propellers with the tips painted blue on many of these aircraft.