Articles

Keeping Aircraft Safe without Radar: The North Atlantic Tracks

September 25, 2019


– I am 35,000 feet above
the North Atlantic, somewhere just south of
the tip of Greenland. And there’s no radar coverage up here, there’s no real-time view
for an air traffic controller to know where all the hundreds of planes
sharing this airspace currently are. So, how do we keep safe? How do we avoid getting
a bit too close to any of them? The answer is down at my destination. GPS: “Continue for 205 miles.” This is the Nav Canada Area Control Centre
in Gander, Newfoundland. And if you’re over the North Atlantic, these are some of the
folks keeping you safe. – The North Atlantic
tracks are the airways that we develop each day
for our eastbound aircraft who fly across from us
over to the UK area. The westbound tracks are produced by our counterpart over in Scotland
via Prestwick Centre. The way the North Atlantic works,
there’s basically two main airflows. During the night time,
our night time here, most of the aircraft leave North America
and fly across to the UK. And during the daytime,
most of those same aircraft return. It’s a 24 hour operation obviously. We start with our day-shift,
comes in early in the morning. We’ll ask all these aircraft to send in
their preferred routes for that night. So I’ll take that into consideration. I’ll also look at weather models. Eastbound aircraft, all the aircraft want
to get into the main jet stream to pick up that tailwind
so they can save money and fuel and time. From all that, we’ll develop
a set of tracks based on that flow, and once the tracks are published
in the morning, airlines then have anywhere from 8 to 10, 12 hours to decide on what track they
want to follow that night. – The tracks can look curved and inefficient
on the flat map projections we’re used to but you’ve got to remember,
they’re great circle routes. They’re the shortest, and cheapest way
around the globe of the earth. And also, the tracks
are three dimensional. Planes can be separated because
they’re on a different track, or because they’re on different positions
on the same track, or by altitude. – It’s a requirement for an aircraft
to give us a position report every 10 degrees of longitude. And we take that information,
and we apply it to the aircraft’s route, and we update our system, and we can kinda predict
where he’s gonna be too. When there’s no radar coverage,
there’s two main forms of communicating with the aircraft over the Atlantic Ocean. We can go through our radio operators,
our flight service operators, and contact them through HF. The easiest way for us, I guess, is like a form of text message,
you could call it. I can just click on a button, and I can tell exactly where that aircraft is
at that point in time. It’s very precise, even without radar. As a normal standard for our tracks, side-by-side, which is
our lateral separation, we’re running 60 nautical miles apart. As time progresses,
airlines get better equipped, we’ll probably have all our tracks
at 30 miles apart from each other. Longitudinal, which is one
aircraft behind the other, we’re running 10 minutes. We can reduce that down to a
five minute standard if airliners are equipped. And vertical, we’re using 1,000 feet. Some nights, you can just
sit out on your patio on a nice clear night, and
you can see numerous aircraft, and they look like they’re all
on top of each other, but basically, they’re all at least 1,000 feet apart,
if not more. They just have to be separated
in one dimension basically. As soon as an aircraft gets too tight
to another aircraft, we interject and say, okay, we need to slow you down,
or speed you up, traffic permitting obviously, right? If a plane has an emergency,
they have contingency procedures. They have their TCAS. TCAS is their
Traffic Collision Avoidance System. For instance, if you had two aircraft and an aircraft did something
it wasn’t supposed to do, climbed up into another aircraft, that plane has a TCAS system that says,
okay you have incoming traffic, you have to climb, or descend,
or whatever the resolution is, right? So as soon as we’re made aware
of an emergency situation, we look at separation, we try
to move what aircraft we can, and we provide a conflict free
clearance for that aircraft, safety being the number one thing here. – Thank you very much to
everyone at Nav Canada, and at the Gander Area Control Centre. You can find out more about them
and the tracks at the links in the description.

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