{"id":13017,"date":"2021-05-03T09:37:04","date_gmt":"2021-05-03T13:37:04","guid":{"rendered":"https:\/\/ops.group\/blog\/?p=13017"},"modified":"2021-05-06T06:02:16","modified_gmt":"2021-05-06T10:02:16","slug":"resisting-the-pull-should-we-still-be-using-magnetic-north","status":"publish","type":"post","link":"https:\/\/ops.group\/blog\/resisting-the-pull-should-we-still-be-using-magnetic-north\/","title":{"rendered":"Resisting the Pull: Should We Still Be Using Magnetic North?"},"content":{"rendered":"

In recent years NAV CANADA has been leading a charge<\/a> to move the industry away from magnetic north to true north<\/strong>. And it makes sense.<\/p>\n

Modern technology has arguably rendered magnetic north obsolete. So why are we still using it? The simple answer is because we always have.<\/em><\/strong> Delve into ICAO Annex 4 and you\u2019ll see that bearings, tracks and radials must still be published in degrees magnetic. But this begs the question – do we actually need it anymore?<\/strong><\/p>\n

When humans first took to the skies, things were different. They needed a directional reference. Back in those days it had to be something simple and light \u2013 enter the magnetic compass<\/strong>. Nature was guiding the way because it had too.<\/p>\n

With modern navigation systems these days all the magic happens reference to true north<\/strong>. Inertial and GPS systems both use simple conversions so that the information can be displayed to crew as a magnetic reference to match our charts and procedures.<\/p>\n

But because we are still using magnetic north as a reference we are forced to deal with magnetic variation<\/strong> – the angular difference between the true and magnetic poles. It is an issue that costs the industry many millions of dollars a year to manage and can potentially lead to serious safety issues if things aren\u2019t handled properly on the ground and in the sky.<\/p>\n

Let\u2019s get science-y.<\/h4>\n

The earth has its own magnetic field. That\u2019s because its outer core contains molten iron. Writhing lobes of magnetic flux surround the earth and meet near the top and bottom of the globe \u2013 the spots we know as the magnetic north and south pole.<\/p>\n

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The earth’s ever changing magnetic field.<\/p><\/div>\n

Open up a compass and the steel needle will align itself to the magnetic field lines around it and hey presto, it will point directly at the magnetic north pole.<\/p>\n

But here\u2019s the problem<\/strong> – molten iron is a liquid, and it moves around. Which means the magnetic north pole does too. It never sits still. In fact in recent times it has put its foot down and is now moving close to 40 miles each year. As of last year, it was about 250nm away from the true pole<\/strong> and headed for Siberia.<\/p>\n

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The constantly moving magnetic north pole over time.<\/p><\/div>\n

The magnetic north pole is of no use to modern navigation systems because it is constantly on the move. Instead, they operate using a \u2018geodetic reference system\u2019 \u2013 a really fancy name for co-ordinates that may impress people at your next cocktail party.<\/p>\n

Two variables, the ol\u2019 lat and long, come together and allow us to define any spot on the surface of the earth.\u00a0All meridians of longitude are anchored to the true north pole<\/strong> because it never changes<\/strong>. It is simply the northern end of the axis around which the world and that globe on your desk spins.\u00a0Latitude on the other hand is reference to the equator which never moves either.<\/p>\n

In fact, the only way either could change is if the earth\u2019s angle of tilt moved too in which case we\u2019d have bigger things to worry about.\u00a0So, when we combine the two we can divide the surface of the world into a grid and pinpoint exactly where we are \u2013 a process that both inertial and GPS systems use to stop us getting lost out there.<\/p>\n

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Lat and Long – anchored by the equator and earth’s axis of rotation.<\/p><\/div>\n

Here are the issues.<\/h4>\n

All of our procedures, bearings, tracks, VOR radials, even our runway designators are still presented in degrees magnetic<\/strong> because the regs say they have to be.<\/p>\n

And because of that every time the magnetic north pole moves, magnetic variation changes and the industry has to get out there and re-jig everything. Literally every computer that references magnetic north in some way has to be updated.<\/p>\n