Why Airports Rename Runways When the Magnetic Poles Move (wired.com) 192
An anonymous reader shares a report: For decades, pilots heading into or out of Wichita Eisenhower National Airport in southeast Kansas have had three runways to choose from: 1L/19R, 1R/19L, and 14/32. Now, at the orders of the FAA, the airport will spend hundreds of thousands of dollars to give itself a makeover. Workers will repaint those huge numbers at the ends of each runway and replace copious signage. Pilots and air traffic controllers will study new reference manuals and approach plates, all updated to reflect an airport whose three runways have been renamed. World, meet 2L/20R, 2R/20L, and 15/33 -- which happen to be the same runways that have been welcoming planes since 1954.
This is not a "What's in a name?" situation. The runways may be the same sweet-smelling stretches of tarmac they've always been, but the world around them has changed. Well, the magnetic fields around the world have changed. The planet's magnetic poles -- the points that compasses recognize as north and south -- are always wandering about. That's a problem, because most runways are named for their magnetic headings. Take Wichita's 14/32. First off, because planes can land or take off from either direction, you can think of it as two runways: 14 and 32. (Pro tip: Pilots say "one-four" and "three-two," not 14 and 32.) If you're looking at a compass, one end is about 140 degrees off of north, counting clockwise. For simplicity's sake, the headings are rounded to the nearest five, and dropped to two digits. So if you're looking down at Wichita Eisenhower, runway 14/32 is the one running from the northwest to the southeast.
This is not a "What's in a name?" situation. The runways may be the same sweet-smelling stretches of tarmac they've always been, but the world around them has changed. Well, the magnetic fields around the world have changed. The planet's magnetic poles -- the points that compasses recognize as north and south -- are always wandering about. That's a problem, because most runways are named for their magnetic headings. Take Wichita's 14/32. First off, because planes can land or take off from either direction, you can think of it as two runways: 14 and 32. (Pro tip: Pilots say "one-four" and "three-two," not 14 and 32.) If you're looking at a compass, one end is about 140 degrees off of north, counting clockwise. For simplicity's sake, the headings are rounded to the nearest five, and dropped to two digits. So if you're looking down at Wichita Eisenhower, runway 14/32 is the one running from the northwest to the southeast.
San Jose (Score:5, Interesting)
The old general aviation runway at San Jose International Airport was runway 29. It was exactly parallel to runways 30R and 30L, they were just built at different times and the pole wandered. The pilots all knew the deal; it seems more confusing to change everything than for pilots to just deal with it.
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it seems more confusing to change everything
In aviation things are constantly changing anyway. That's one of the reasons airlines adopted electronic charts on iPads. When you're dealing with something as descriptive as angles the only confusion you could possibly create is by not updating the description to reflect the actual situation.
Renaming runway Bob to runway Joe creates confusion. Renaming runway 29 to runway 30 when your instruments will say on them 300 degrees when you're on approach does not.
Re: San Jose (Score:4)
That makes sense. In San Joseâ(TM)s case, 30L and 30R were pairs with exactly the same length, width, etc, where 29 was a skinny short oddball.
Re:San Jose (Score:5, Insightful)
If you're dealing with only 2 runways, your argument is valid - why update for a minor adjustment.... but as a pilot, I can tell you that it's important when there's more than 2 tangential runways, especially in low visibility and/or in a non-IFR equipped plane.
One runway can be labeled 18 and a tangential runway could be 20. If the pole shifts, requiring 18 to be 19 now, you can get confused and come in on approach for 20, potentially causing an accident or other runway incursion. This is an extreme example, but it's a possibility. The tangential runways are the big issue and are why having accurately numbered runways are so important. The more pilot load you can remove, the safe everyone is. Having to think about and mentally calculate a change can cause a serious diversion of attention during a tense landing situation. Something you *really* don't want to happen.
Re:San Jose (Score:5, Informative)
The numbers get updated (God knows why) when the poles move.
Pilots also know why.
When on final approach, the number you see on the end of the runway should match what is on your compass. The compass is the "navigational aid of last resort", as it does not require any mechanical, vacuum or electrical assistance to work. How you set up for that runway...even how you approach the airport...depends on that number. Flying into an unfamiliar airport with screwed up runway numbers will add an extra layer of unnecessary complication.
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Agreed. There are also structural components in the plane that screw with the compass, requiring a correction card.
But still, all us pilots know why the numbers need to be periodically updated.
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ORD (Chicago O'Hare) is a case in point. After the latest round of runway-building, they wound up with FIVE east-west runways, all of which are parallel to within a couple tenths of a degree. The northernmost two are 09L/27R and 09R/27L, with the others being 10L/C/R / 27R/C/L.
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Names and Method Inconsistent (Score:2)
For simplicity's sake, the headings are rounded to the nearest five, and dropped to two digits.
This is not consistent with the names given i.e. '1' or '2' since these have only one digit remaining. Either these names should be '01' or '02' or the method is something even simpler: round to the nearest ten and drop the final zero.
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Numbers are painted with the leading zero.
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search in airnav.com and give us an example of what your claiming.
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Evidence: US does omit the zero (Score:3)
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The summary was wrong here (writer didn't understand how rounding works)
Dammit, Jim - I’m a Writer, not a Mathematician!
As any DBA knows... (Score:3)
Don't index your objects using Natural Keys [wikipedia.org] that are a function of slowly changing values. Yes, the naming convention has a value in identifying location as a function of geographic location, but it's a function of a projected geolocation (magnetic field strength) that turns out to move.
Instead of spending all the money renaming/renumbering the runways, and renumbering them again a couple of decades from now, an engineer would say create a surrogate key that will be constant for all time. Heck, Alpha Beta Gamma, etc would be just as useful in this world of GPS.
Re:As any DBA knows... (Score:5, Insightful)
There are a *lot* of aircraft out there that don't have GPS systems built in, and even if they are, they are subject to failure. Airports are built to be properly usable to the lowest common denominator of available technology, and in an emergency, the lowest common denominator may well be the basic magnetic compass.
Emergencies aside, many aircraft (especially home built's, ultralights, and a lot of other non-commercial aircraft) don't bother with things like GPS.
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I can't remember the name of the band, but there's a good piece of heavy music that starts with the lyrics "747 coming down in the night / no power, no runway lights". Which is a pretty unlikely situation - both the multiple power systems on the aircraft failing, and those on the ground. But what the fuck? The exact point of having a MAGNETIC compass as a fallback from all other systems is that it requires precisely (not approximatel
Re:As any DBA knows... (Score:5, Informative)
They should just use the geographical headings instead of magnetic headings.
Except, the compass on board the airplane that needs to use the runway ... is magnetic. By definition.
Re:As any DBA knows... (Score:5, Interesting)
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I don't know about charts for aircraft, but I know Canadian standards for nautical charts include markings for magnetic deviation (and notation on rate of change so you can still use an older chart). Since pilots are already required to frequently check NOTAM updates, I don't see a big deal in having them remain aware of local magnetic deviation.
Mark the runways by geographical heading, put the magnetic deviation at the airport/aerodrome on the chart. That's got to be one of the simpler things a pilot has
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As someone that has had the engine go silent at 7,000 feet, I can state with authority that you have no clue of what you're talking about. The stress of an emergency, "do it right the first time or die" situation has so much adrenalin pumping through your veins that basic math is near impossible. I was making radio calls that I was north east of the airport, when I was south of it (north east was where I was headed when the engine quit). Reading minuscule numbers off a sectional in order to calculate a d
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You get that runways already are marked to the nearest 10degrees, right? Are you upset that you're not heading for runway 273.5 instead of 27?
Aviation has already decided that a difference of 10 degrees doesn't matter.
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No. We've decided that we can live with the heading plus/minus 5 degrees. So, should plus/minus 10 be ok? Plus/minus 20? Heh! I know just add one MORE bit of information to an overcrowded, barely legible sectional to say "Our runway markers don't mean a damn thing! It's just random numbers."
Or, you could keep the marking updated and relevant.
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Odd that you should talk about Canadian standards and then say this:
"it's not like a geographically marked runway will be off by enough to confuse with another if you're using magnetic headings by mistake."
The magnetic deviation in much of Canada is somewhere in the neighbourhood of 20 degrees.
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>Former air traffic controller/pilot here.
Informed opinion then, awesome! (No /s tag, I'm serious) It'd be nice if you had posted with an account, though, to confirm continuity of the comment chain if nothing else.
>The suggestion to mark runways by geographical heading is inane, since aircraft navigation is by magnetic heading and local magnetic variation may make the geographical heading substantially different from the mag heading,
Magnetic declination in my region runs about 10deg. Keeping in mind
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In this context being within about 30 degrees of (magnetic) latitude of the (magnetic) pole qualifies as "close". We're Nearly 40 degrees from the pole, but I still re-calibrate my compass every couple of years (it has an adjustment for that ; why would you buy a compass that didn't have that?), and there are over 100 square miles of
Re:As any DBA knows... (Score:5, Informative)
Pilots already know how convert between magnetic and geographical headings, I would think. I think the small inconvenience is better than having outdated runway markings or having to renew them every now and then (not only on the runways themselves, but also on all charts).
Um, no. First of all, the conversion isn't consistent from place to place. For example, as you move across degrees of longitude, the angular difference between the magnetic and geographic north changes. So, your conversion changes. The last thing you want to do to a pilot is to add more shit on his plate, trying to do calculations when he could simply compare his compass and the giant number printed on the runway.
FWIW, I was a private pilot in the 80s & 90s, but gave it up when my kid was born...just didn't have time.
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By the time you can see the runway, your aren't looking at the wobbly compass. If you can't see the airport, your using ILS (nor GPS or VOR or NDB) and don't care what the compass says either. It only matters when you are very far away and if your using that, you better know what the adjustment factor is down to a 1/2 degree.
And it doesn't work at all in way too many places. Rural areas with iron ores or near parts of Lake Michigan or much north of the US border and it all starts to be very useless. Th
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If you've never looked down at the runway number, you're doing it wrong, just google "landing at wrong runway", and see how often it happens. Harrison Ford is a recent well known example. And, when do you EVER need a 1/2 degree for anything? I've never seen a piece of avionics that took less than a degree, but than I haven't flown in a few years. As for the iron ore deposits, your maps all have that plugged in. As for your arguing it for decades, I've never once heard a pilot complain about using magne
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By the time you can see the runway, your aren't looking at the wobbly compass. If you can't see the airport, your using ILS (nor GPS or VOR or NDB) and don't care what the compass says either.
Clearly you've never been caught in IFR conditions in an aircraft that isn't IFR-equipped.
When all you have is a windscreen full of white and rain, a voice giving directions in your ear, and a magnetic compass, the last thing you want to be doing is calculating the magnetic/true north differential for your current lat/long in your head. When you've been told you're on the correct vector for runway 29, you want to look at your compass and see 290, nothing more, nothing less.
Re: As any DBA knows... (Score:2)
If you would fly into imc without the necessary preparation you may as well just kill yourself and save everybody the trouble
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Pilots already know how convert between magnetic and geographical headings
An operator of any critical equipment that could cause damage or injury can likely do a lot of things, but humans are fallible. The ultimate goal is to take as little attention away from the immediate situation at hand as possible.
It doesn't matter if you're flying a plane or changing setpoints on gas compressor, for safety you don't rely on anyone thinking.
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They should just use the geographical headings instead of magnetic headings.
In the northernmost parts of Canada we do. The magnetic variation is large and varies rapidly in the high Arctic, so all headings (runways, navigation, etc.) are in degrees true. With little in the way of ground infrastructure all altitudes are standard pressure, i.e. flight levels.
A couple of airports around here (CZBB, KBFI) recently renumbered runways. My home airport's main runway (CYNJ) 01/19 has magnetic headings of 015 and 195. One more degree and they'll think about renumbering it.
...laura
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Anyone who has done chartwork under pressure just shivered at that suggestion. A good navigator gives the pilot/helmsman headings in magnetic so the person who's supposed to be busy steering doesn't have to worry about doing extra math. Especially in a hurry in their head.
Is this that critical anymore? (Score:2)
With the advent of GPS and advancements in ground-based technology able to offer redundancy and higher accuracy, is there a reason we're still this concerned about maintaining a naming schema based on compass readings? Are there that many aircraft still in use today that use nothing but a compass for navigation?
This is kind of like making sure every new car sold comes with a paper map, and every new house comes with a printed copy of the Yellow Pages.
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Not all aircraft have GPS navigation, or even electrical systems to support one. Yes, some aircraft lack an alternator and battery - thus they have no electrical system and are not required to have a transponder or other electronic navigation equipment, other than perhaps a battery-powered radio. The engine's spark plugs are fired by magnetos turned by the engine itself (so yes, these types of planes also need to be hand-propped to start, because there's no battery to juice a starter)
Long story short, GPS o
TLAR landings (Score:2)
All landings end with a pilot looking out the window and deciding "yeah, that looks about right". The magnetic compass and the data it generates are one piece of a much larger puzzle.
Yes, I'm aware of things like Category 2 ILS, but they don't do stuff like that unless they absolutely have to.
...laura
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Yes, quite a few aircraft don't have GPS. Flight-rated instruments are very expensive. Also, the electronic widgets fail, usually when you'd really like to have them.
Planes (and boats) are also required to have paper "maps", with the possible exception of some commercial airliners that have managed to get electronic charts certified (not sure if they still need at least one paper backup set).
I'm a qualified celestial navigator. That's with a sextant. I hope it always remains an interesting hobby, but I
Discovery's "Mayday" won't run out of episodes (Score:2)
So, one, two, or three plane crashes before someone blames another miscommunication on fog? Just another airport for me to avoid. Love it.
Automatic alignment is the solution! (Score:2)
I don't get it. One can easily save them the work of renaming the runways (painting and what-not) by inserting a ball bearing in the middle and magnets along the runway! It will automatically align to the magnetic field. Sshhh... some people.
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No, they just need to move to circular runways. Odd proposal, but could be interesting.
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The worst part of this is pilot coordination at a busy airport. Say you have three student pilot's in the pattern, an older pilot trying to shake off the rust, a formation team coming in, and a couple of guys out just enjoying the day. I've been at the airport in this sort of traffic. Now, what exactly is the take-off and landing zone? Everybody needs to agree, or they're going to be running into each other.
Time for RNS (Score:5, Funny)
The Runway Naming System allows pilots to send RNS requests to the local Runway Naming Service which of course run on the local Runway Naming Server (Be aware the same acronym holds several correct definitions). Also I t is appropriate to use the designation "RNS Server", "RNS Service", or "RNS System" even though it may be redundant.
These local RNS databases are owned by the airports and are synchronized with the root RNS server several layers up in the RNS hierarchy.
While planes may choose to make RNS requests directly from the root server, for traffic management (bandwidth, not air traffic) they are strongly encouraged to maintain their own local RNS server that caches RNS data from RNS servers at levels lower from the root and geographically local to them. This may be accomplished via RNS Zone Transfers.
It must also be remember that RNS name updates may take several hours to propagate through the RNS hierarchy and for all RNS servers to update with accurate information. So while pilots may have a local cached copy while in flight from their local RNS server, care must be made to verify the RNS data with the authoritative RNS server while approaching the destination airport.
As an example the Wichita "Gandalf" runway upon local RNS resolution currently returns 14/32.
There have been recent reports of RNS spoofing and RNS cache corruption attacks being used, as well as malicious RNS database updates pushed to the RNS root servers and propagated across the RNS network. We are currently working on the next generation of secure RNS Services known as RNSSEC.
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Longer term fix. (Score:3)
The molten iron core of Earth is to blame. All we need to do is wait for the magnetic north to be where we want it, then quickly cool the core so it solidifies in place.
Even with numbered runways..... (Score:2)
Even with numbered runways, the occasinal pilot still goofs things up. They're supposed to check their compass against the runway numbers when they're at the takeoff point. Even so, one pilot long ago had his compass set not SIX degrees of magnetic variation, but SIXTY. Instead of landing in London they ended up running out of gas over the Sahara. Another time, a cargo plane took off in the 180 direction from Marseilles, and they crashed into a tall hill miles away.
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Fake News! (Score:3)
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Correction: you probably meant anthropogenic, not anthropomorphic.
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Anthropogenic magnetic pole shifting is a hoax! The poles have always been where they are, and the Fake Liberal Media just wants you to believe that they're moving to advance their left-wing agenda!
Darn right! And if you don't believe it, the proof is that the so-called movement is ALWAYS TO THE LEFT!!!
Do they still use magnetic cpmpasses (Score:3)
Do they still use magnetic cpmpasses in commecial aviation?
Y thought it would be based a mountain
on GPS thwaw days
They were ysing inertial navigation systems in airliners back in the later 70's
when Air New Zealand were flying scenic trops to Antarctica
of course if someone transposed numbers when typing in the waypoints you could still run into
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Do they still use magnetic cpmpasses in commecial aviation?
At least as a backup, yes. Both the "whiskey" variety and the Hall effect variety.
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Do they still use magnetic cpmpasses in commecial aviation?
Yes.
And commercial aviation is not the only segment that airports are built for.
compass heading? (Score:2)
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to the rescue (Score:4, Funny)
Bigger problem looming (Score:2)
Geologists are concerned that the magnetic poles might soon go through one of their cyclic reversals, flipping north and south. This would result in a number of years where the earth has no net magnetic field.
If that happens, the FAA will have to direct airports to rename every single runway in this country to "NULL".
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Nah! Pilot's will just have to fly their planes between the falling skyscrapers on their way to finding the hidden arks that will save the vestiges of the human race. The runway will only need to be realigned after the continents have finished shifting.
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Geologists are concerned that the magnetic poles might soon go through one of their cyclic reversals, flipping north and south. This would result in a number of years where the earth has no net magnetic field.
I thought we didn't yet know how long the reversals take?
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"concerned" is a little strong. "aware" is how strong it gets for pretty much everyone. That guy on Discovery Channel, Munchkiniko "It's Aliens" Poopants (or whatever his name is) notwithstanding.
"will", not "might"
aperiodic, but fairly frequent. Most people, when told something is cyclical, think "it'll happen every 100,000 years or what ever", then think, "it hasn't happened for 50,000 years, so 50,000 years
Thank God (Score:2)
Thank God for Slashdot where this can be discussed, because the aviation boneheads who came up with the runway naming conventions obviously never thought any of this stuff through! Moreover, none of the reasoning has ever been documented by those (Government, naturally) selfsame boneheads.
Aviation could use an all-out standards update (Score:2)
Reading this aviation stuf and the details in the comments reminds me of messing with AICC e-learning data back in 2002 and trying to convert it into XML or something other more useful. This was an amazing head-trip. You could smell the punchcards and hear the noise of the 60ies batch processors simply by looking at the raw data files. n-dimensional relations were (are) covered across files, data access based on column count, 126 character ASCII (and not a single one more!) more and some other awesome old-s
Actually it is worse (Score:3)
Problem with outdated information (Score:2)
Online sources of information are probably updated immediately when the runway numbers are repainted. However, many pilots fly with paper charts and airport directories. Either they fly old planes without modern avionics, or they simply want information that will survive a computer hardware failure. These paper documents expire in a few months and _should_ be replaced after expiration. For at least a few months (possibly longer), pilots rely on old information from paper charts and directories to get run
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There are companies that provide these services on a subscription basis to the airlines. Jeppesen (a Boeing owned company) is probably the largest name in this business. Almost every single modern commercial airline operates iPads issued to each pilot with the chart information.
Paper charts are for hobby/amateur pilots or a last resort if both iPads (and on bigger planes EFBs) don't work any longer.
Airlines routinely chuck out boxes of old charts and replace them with new ones. The only person without a
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Or a pilot.
His post is a statement of the legal responsibility of a pilot. It may surprise you, but there are professions, even hobbies, where you have actual responsibilities and virtually all of the practitioners take them very seriously.
If you land on the wrong runway because you didn't update your chart, the aviation authority in your location will not be pleased.
Re:Wrong Solution (Score:4, Interesting)
Runways are numbered in 10s of degrees. 19R is the right hand runway where the approach is at 190 degrees.
The magnetic poles haven't shifted by 10 degrees, so the better question is why it was labelled 19R in the first place.
Re: Wrong Solution (Score:3, Informative)
its says they round to nearest 5 then truncate to two digits. Perhaps it was 197-->198.
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No, it's saying if you are building a runway, it would be wise to try to be angled at the center of an interval, rather than right at the edge of an interval. If it is going to round to 190, then try to exactly be 190, and then it's very tolerant to fluctuations and still be accurate enough.
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If it is going to round to 190, then try to exactly be 190, and then it's very tolerant to fluctuations and still be accurate enough.
That's not how this works. Runways are built to ensure aircraft have their nose pointed into the wind as much as possible. So if the wind comes from the west during most time of the year, they will build runway 270/90 (27/9). Another matter is, as said here, obstacles. But most of the times airports are built when there are few surrounding buildings.
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No, it's saying if you are building a runway, it would be wise to try to be angled at the center of an interval, rather than right at the edge of an interval. If it is going to round to 190, then try to exactly be 190, and then it's very tolerant to fluctuations and still be accurate enough.
The primary concern for planning a runway direction is the prevailing wind. It's very difficult for a pilot to land a plane in a crosswind. (There are many YouTube videos on this subject.) Therefore, runways are planned so the plane is flying into the wind as often as possible. If the wind typically has a heading of 185, then that's where the runway goes. Making the heading 190 will only make it more difficult to land the plane.
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It's very difficult for a non-pilot to land a plane in a crosswind. Once your instructor pounds the procedures into your head and you've practiced a bit, landing a plane in a crosswind isn't a big deal. Sometimes it's fun, especially when you can land straight ahead on one main and gradually bleed off airspeed until the other main touches down. That'll put a big smile on your face!
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The 1974-75 Cessna 172 has a maximum demonstrated crosswind of 17 MPH (15 knots). This is the maximum crosswind component during which the aircraft has been landed by the manufacturer test pilot. Info from http://www.beverlyflightcenter.com/wp-content/uploads/2017/05/172SPEEDmph.pdf [beverlyflightcenter.com]. I'd be interested in seeing the equivalent for a similar sized Piper.
Re:Wrong Solution (Score:4, Informative)
From TFA: "Things only change when the compass reading shifts a certain amount. Say the pole shifts such that the heading of 258 degrees is actually 259 degrees. That still rounds to 260, and the runway would still be called 26. But if the compass reading goes from 258 to 254, you’re now looking at runway 25."
Re: Wrong Solution (Score:5, Insightful)
The deviation between magnetic and geographic north depends not just on the poleâ(TM)s degree of movement, but also the angle you are away from the pole. In some areas of the US, yes, the movement has been about 10 degrees since the mid 20th century.
Re:Wrong Solution (Score:4, Informative)
magnetic shifts aren't universal. Well, they are, but the measurement of how much they shifted isn't universal. If one is inline with the direction it moved, there is virtually zero change in magnetic compass heading, but if one is perpendicular to its movement, then there is a very large change. This rate of change gets larger the closer one is to the magnetic pole.
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The magnetic poles haven't shifted by 10 degrees
They don't need to move 10degrees, they just need to move 1degree when your policy is to round to nearest. That's the problem with rounding. The difference may be represented as 13 and 14, but the actual difference could be 13.4999 and 13.5000. As soon as you round something you lose the information underneath.
Re: Wrong Solution (Score:2)
Isn't everything from 127.51 to 137.4 represented as 13?
What? No. I have no clue how you got those numbers.
Anything between 125 and 135 is 13.
Re: Wrong Solution (Score:2)
Oh I see.
Yeah, the article is confused. There's not much point in "rounding to the nearest 5" if you're then just going to drop the five.
The easiest way to think about it is that you divide the heading by 10, them round to the nearest whole number. Eg. 173 degrees becomes 17.3, round down to 17.
Re: Wrong Solution (Score:2)
Yes there is, because you get a different result for 156 -> 15 and 158 -> 16.
Re: Wrong Solution (Score:2)
Yes, I know you get a different result, but that just makes things even worse for that scenario. The whole point of numbering runways the way we do is to get them as close as possible to the actual bearing while using only two digits. So why the hell would you round 177.4 down to 175, and then turn it into 17, when 177.4 is much closer to 18?
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I guess that's what they are doing at the BER construction site....
http://www.der-postillon.com/2018/01/sturm-ber.html [der-postillon.com]
Better Solution (Score:2)
not a litte bit (Score:2)
Consider JFK's longest runway. It's around 14,511 ft long. Even a 1 change will mean more than "a little bit to one side".
Also, runways are typically oriented with regard to prevailing wind direction, so moving the runway may not be optimal for landings and takeoffs.
degree symbol (Score:2)
That's 1 degree. Who knew /. cannot accept degree symbols?
Re: not a litte bit (Score:2)
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Magnets, always with the magnets.
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can it be possible that they are ...
https://imgflip.com/i/22zals [imgflip.com]">img src="https://i.imgflip.com/22zals.jpg
Re:More evidence of climate change? (Score:4, Interesting)
You seriously think that surface conditions have an effect on "the global geodynamo" (the Earth's core)? The wandering of the magnetic poles isn't the result of mysterious changes thousands of miles below the surface; in general it's caused by variations in the Earth's wobbling as it spins on its axis. According to this [sciencealert.com], the relatively recent acceleration of pole movement is the result of a water deficit in India and the Caspian Sea region.
The magnetic poles have reversed many times in Earth's history. According to this [dailygalaxy.com], over the last 20 million years a pole reversal happens every 300,000 years or so. It's been 780,000 years since the last one, so maybe we're overdue.
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"You seriously think that surface conditions have an effect on "the global geodynamo""
And then you continue to explain that that's exactly the case? And link to an article that states that it was generally believed among scientists that the mass redistribution from melting ice caps are the main cause, until someone proposed that smaller climate/human related mass changes at 45 deg latitude have more impact.
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You do realize that a compass doesn't get software updates. Right?
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Re: Why so much? (Score:2)
Pilot maps have to be updated. The AIS has to be updated. All the jeppson approach plates have to be updated.