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Maybe time to change from Magnetic to True? (and proposal in Canada)

102 Posts

25-Oct-22 06:54

Interesting read, especially the FAQ which addresses GA in paras 7 and 8 and which is mostly BS was written by somebody who has never flown a plane.

Administrator

Shoreham EGKA, United Kingdom

21-Dec-22 16:48

Just got this from IAOPA:

Which North is better?

Sometimes when topics land on your desk, you don’t really know what to do with them at first. Are they relevant to our members, what is there to do? Through our IAOPA representative at ICAO Frank Hofmann (the one with the success with the corrections to the rescue and firefighting service), news reached us that several states, led by Canada, have approached ICAO where the increasingly accelerated migration of the magnetic poles is a concern. These states want to move away from navigating with reference to the magnetic North pole and instead navigate with reference to the geographic North pole, which so far in Canada has only been done in the far North.

By way of background, when observations began in the 19th century, the Magnetic North Pole moved Northward from its position in Canada at about 70°N at a rate of 10 to 15 kilometers per year, but since 1990 the rate has been about 55 kilometers per year from the North Pole toward Siberia. This means that VORs and runways set to magnetic North must be readjusted more and more rapidly according to the current declination, especially in Northern countries. For runways, this is done by hand, using many buckets of paint to repaint the numbers. Also on approach sheets, all courses are given in terms of magnetic North and have to be corrected in the databases and on paper charts.

In Central Europe this is not a big problem, because the declination (or variation) is 1-3 degrees, depending on the location, with an annual change of about 5-10 arc minutes. That is one degree change in 6-12 years. On Spitsbergen the situation is different: There you have a variation of 11° E, with a change of up to 25 arc minutes per year, so one degree change in a little more than two years.

In the maritime sector, people worldwide have long since switched to Magnetic North / “True North”, should we now do the same in aviation?

For us, it is important to carry out an impact assessment, i.e. an analysis of the effects. What would change in flight procedures, does training have to be changed and retrained, is there a need for expensive avionics retrofits? That’s where you have to look at each area of aviation separately:

- According to EASA, the large airliners can convert their navigation to magnetic North quite easily with their flight management systems; for some regional airliners, the situation is still different.
- In General Aviation under VFR, the problem is also manageable: because even today, the vast majority of pilots simply fly along the magenta line between waypoints on the GPS. If the current course over ground corresponds to the desired track, one arrives exactly. However, the declination must still be included in the navigation when navigating with the compass.
- It could be problematic in general aviation under IFR if the navigators cannot be changed over without problems. We are currently working with our international colleagues at IAOPA to gain an overview of this issue, which will then lead to a coordinated statement at ICAO. Can you think of any aspects of this topic that are important? Please write to us at [email protected] and mention the keyword “True North”. We will gladly take up your suggestions and incorporate them into our statement!

Are they really going to do this??

Administrator

Shoreham EGKA, United Kingdom

21-Dec-22 17:21

Peter wrote:

It could be problematic in general aviation under IFR if the navigators cannot be changed over without problems.

I don’t understand this.

LDZA LDVA, Croatia

21-Dec-22 17:39

Emir wrote:

Peter wrote: It could be problematic in general aviation under IFR if the navigators cannot be changed over without problems.
I don’t understand this.

I read it as if IOPA meant that ALL the IFR GA have to replace their NAV devices into the new ones (that don’t exist yet?), and if that does not happen (?!), that will be a problem.
And the VFR comment was the most ignorant and patronising…

EGTR

21-Dec-22 20:34

And the VFR comment was the most ignorant and patronising…

I read it as they’re clueless of things they’re writing about.

LDZA LDVA, Croatia

22-Dec-22 07:58

What would be the actual process to change to magnetic?

It would be a huge amount of work. Not so much flying (where most of us is barely aware of the exact track value) but all the publications, procedures, etc…

Administrator

Shoreham EGKA, United Kingdom

22-Dec-22 08:27

What would be the actual process to change to magnetic?

For publication & procedures, I don’t think it’s different than the normal process of changing magnetic variation (every 6 months in Canada and every 5 years in other places), regular VOR servicing, regular runway painting…the bonus is less hassle dealing with magnetic errors in avionics: compass swing & card update

The elephant in room is ATC (magnetic) vectoring to use (true) heading on their radar screens: changing anything in the way how aircraft are separated then everyone cries about the loss of safety and banalisation of ATC work

For true north in avionics, I am sure mechanical HSI can be auto-slaved to true north but may require approved GPS source plus non trivial pile of work, for EHSI things are easy: they already fallback on true heading (or TRK) when you lose manometer

Last Edited by Ibra at 22 Dec 08:33

Paris/Essex, France/UK, United Kingdom

22-Dec-22 09:08

Ibra wrote:

I am sure mechanical HSI can be auto-slaved to true north but may require approved GPS source plus non trivial pile of work,

I’m sure they can not except by a substantial modification. You would have to use a unit that interface between the magnetometer and the HSI and “rotates” the signal. Modifying the mechanical HSI itself is out of the question.

for EHSI things are easy: they already fallback on true heading (or TRK) when you lose manometer

They revert to true track, but here we’re talking about true heading. But sure, if the EHSI is hooked up to a GPS with a magnetic deviation database/model then it’s “just” a matter of programming.