March 8, 2017
In the event of an in-flight contingency while flying in the new half-degree (25 nm) reduced lateral separation minima (RLatSM) tracks across the North Atlantic, a new procedure for diversion or 180-degree turn-back is an option, but not a required SOP change.
The language modification was recently published in the North Atlantic Operations and Airspace Manual Update – NAT Document 007 – North Atlantic Operations and Airspace Manual (v.2017-1), Chapter 13, Special Procedures for In-Flight Contingencies. View the modification. (PDF)
Mitch Launius, an instructor pilot and NBAA International Operators Committee Region IV (North Atlantic) lead, advised that pilots “not operate in the RLatSM tracks if they’re new to the North Atlantic environment. They can fly above, below or outside the organized tracks.”
However, if operators are flying the tracks and need to turn back, according to the UK Aeronautical Information Publication (AIP) ENR 2.2-25 – the governing regulatory requirement ∇ the stated procedure is to first turn within your lane, then ascend above FL410 or descend below FL280 once you have reversed course.
Launius said modern business aircraft can turn 180 degrees within the 25-nm track. However, “if you turn too wide – due to incorrect bank angle, excessive speed or crosswind – you could end up overshooting and going into the adjacent airspace of another aircraft,” he added.
The new option, which was proposed by some airlines, involves offsetting from the track by 15 nm, still flying in the same direction, then descending below FL280 (where the separations are two degrees lateral, i.e. four times as wide), or climbing above FL410 (where lateral separation is two degrees and vertical separation is doubled to 2,000 feet).
Launius said he is concerned about allowing too many options, especially in a potential crisis. “When a contingency occurs, the pulse rate goes up and you get flush with adrenaline. You’re going to start reacting and try to go to what you know,” he said. “And if there are multiple options, you might conflate one procedure with another and end up in a compromising position.”
Currently, three core NAT Organized Track System (OTS) tracks are operating in the Gander and Shanwick oceanic control areas, FL350-390 inclusive. Once Future Air Navigation System connectivity issues are resolved, all OTS tracks are expected to transition to half degrees.