Magnetic Pole Shift Affects Tampa Airport

RFSSystems writes "I thought this was an amazing and rather rare phenomenon and wanted to share. 'The airport has closed its primary runway until Jan. 13 to repaint the numeric designators at each end and change taxiway signage to account for the shift in location of the Earth's magnetic north pole.' It appears that the shifting poles have begun to affect air travel in a somewhat modest way. Could this also be the explanation for the falling/dead birds this week?" I hope the gradualists are right, but scenarios for rapid magnetic pole shift are fun to think about.

Comments

Happens all the time

[Anonymous Coward]

The airport I work at has a second set of signage from when the gradual shift occurs in cycles, making for a 10 degree change in the direction of the runway. Ie, here it will be runway 10-28 becoming runway 09-27. Has nothing to do with birds, happens every decade or so. Ten years after that, itll be back to what it is now.

Re:Happens all the time

[WuphonsReach]

I am astounded they would be orienting runways according to the magnetic poles and not the "true" cardinal directions.

Maybe because a magnetic compass will (almost) always work when the more advanced instruments don't?

How do you propose that pilots figure out what the "true" cardinal direction is as they approach the airport? While working through their landing checklist, monitoring other air traffic, weather, and everything else that has to happen before the wheels touch down?

I guarantee they don't have time to do a star-sighting.

Re:Happens all the time

[natehoy]

Both.

The regulations are there for a very good reason. Every airplane needs a magnetic compass on board, because in all the years of using magnetic compasses, they aren't known for running out of batteries or needing to be rebooted at a critical moment or failing because a programmer fucked up and you just crossed time zones. Electronics can easily accommodate using mag north, magnetics cannot as easily accommodate using true north. So we use the system the simplest system can accommodate easily, and the more complex systems that are MORE than capable of adjusting for it do so.

Hobbyist planes are where professional pilots learn to fly, and most of them start out using a magnetic compass as their primary directional instrument (or at least use that as input to set a a directional gyroscope that's easier to read). That way, when the pro pilot is up there and the instrument panel suddenly goes dead in a puff of smoke, there's no reason to write off the lives of the passengers on board. The pilot knows where he's going, and this is due in part to the simple instruments that are on board, and in part to the fact that he's prepared in case this happens.

You learn to fly using shit that don't break, then you get to play with the fancy doodads later, but you never forget how to use the shit that don't break. People's lives depend on that.

Not rare at all

[Urban Garlic]

Changing magnetic deviation due to movement of the magnetic pole goes on all the time. Runways are numbered according to their magnetic heading, plus or minus five degrees, and they have to keep them up to date, is all.

Two seconds of googling found this comment thread discussing a different runway-renumbering from July of 2009.

Obviously not enough airplane geeks around here...

Re:Not rare at all

[TheCRAIGGERS]

How am I supposed to panic uncontrollably when level-headed people like you are around?

Seriously speaking, thank you (and people like you) for being around.

Re:Not rare at all

[trollertron3000]

I'm a private pilot here in Tampa and I can actually see the runways from my parking garage here south of TIA (actually KTPA). They teach you this during your private pilot's course so it's known to all pilots that deviations occur and poles shift. Magnetic deviation is accounted for in your training and you use other tools to compensate.

In fact when I fly along I'll use a chart of known magnetic deviations in the area I am flying to find true north. I also have two instruments I can use - a heading indicator and an actual magnetic compass. We set the heading indicator, a gyroscopic-based instrument, using the compass while flying straight or on the ground. This will need to be adjusted as we fly along typically, it "creeps". We use the heading indicator over a magnetic compass because trying to fly accurately with a compass is like trying to balance a unicycle. it's not easy and you chase the dial. We also use GPS but the ultimate navigation instrument for a VFR pilot like myself is a set of eyeballs, we use dead reckoning using navigation landmarks noted on charts or known to us.

The pilots flying into KTPA will most likely be commercial pilots flying an instrument landing approach. This will not effect them much at all but the runway needed to be shut down so it could be repainted and fit into the FAA regulations. It's as simple as that.

Not sure why I added all that. Probably because no one else did.

Difficult to change, but not that rare.

[Xocet_00]

The movements of magnetic north have, on many prior occasions, caused airports to have to redesignate their runways. Since it requires updating of all the charts that aircraft are required to carry (not to mention signage on the ground), it's often deferred as long as possible. Tampa doing this isn't really that significant, although I admit that it's kind of neat in a visual-manifestation-of-invisible-phenomenon kind of way.

Wikipedia subsection on the subject.

Re:Difficult to change, but not that rare.

[$RANDOMLUSER]

Here's a really cool animated gif from Wikipedia, showing the magnetic declination changing over time.

Re:Difficult to change, but not that rare.

[fuzzyfuzzyfungus]

You do have to pity the chaps responsible for repainting the runways of aircraft carriers whenever their orientation relative to the earth's magnetic field changes...

Re:Difficult to change, but not that rare.

[Orion2]

Changes to stuff like this are introduced on a cycle once every 28 days - called an "AIRAC cycle". The AIRAC is synchronized all over the world, so all the systems, charts and the like on the ground and in aircraft can be updated accordingly. Obviously there is some lead time ahead to allow for publication, distribution and update of the information and depending systems.

Imagine if it was only once a year - every change affecting more than one airspace user or aviation service provider in the world would have to be introduced together. This would in consequence mean that you could only open a new runway, introduce a departure procedure or many more things on that date.

On top of this there's a notification scheme for distributing info like non-functioning equipment, temporarily closed runways (for which you don't change maps forth and back), procedures to adhere, info about an airshow and the like. This is called a NOTAM - short for NOtice To AirMen.

Actually somewhat common

[ASimPerson]

This has happened before, and it'll happen again.

Airport runway numbers are based off their magnetic headings with the last zero removed. So a runway that runs due south/north is 18/36 (i.e., it faces 180 degrees south and 360 degrees north - 0 isn't used). A runway that runs due east/west is 9/27. And so on. When there are parallel runways facing the same direction, the L, C, and R designations are used. A pair for parallel east/west runways are 9R/27L and 9L/27R.

So as the pole drifts this sometimes causes runways to have be renumbered. One previous example is Reagan-National airport in Washington, D.C., where runways 1/19 and 4/22 were originally 18/36 and 3/21.

Magnetic/Spin Axis Confusion

[Elder Entropist]

Your "rapid magnetic pole shift" link is to an article about the (fairly ridiculous) rapid shift of the axis of rotation of the planet rather than the magnetic pole. The two really should not be confused.

Birds

[rewt66]

The birds got confused by the discrepancy between runway numbers and magnetic north, couldn't figure out where to land, ran out of fuel, and crashed?

Re:For the airplane geeks...

[Martin Blank]

The compass requires no electrical power.

I fly a Cessna 172S equipped with a Garmin G1000. It's a glass cockpit that makes life much, much easier, but I still have a few analog instruments: compass, attitude indicator, airspeed indicator, and altimeter. All of them function on principles in place on aircraft for many decades now, and provide a layer of reliability in case just about everything goes wrong. I can lose the entire electrical system and still be able to fly to the best landing site available, because the compass is based on the Earth's magnetic field, the attitude indicator is based on a vacuum-driven gyro (the vacuum pump is mechanical and run by the engine), the altimeter is based on the static air pressure, and the airspeed indicator is based on both the pitot tube and the static air pressure. (The engine spark is provided by magnetos that will keep providing spark as long as the engine is turning - no battery required.)

There are complications when flying at night, but that's why I carry a hand-held navcom radio and a couple of flashlights with me in my flight bag.

Re:I wonder

[Machtyn]

Are you pondering what I'm pondering?

Why, yes, Brain! I do think it is a bad idea to eat tater tots that were saved in my pocket from this afternoon's lunch!

Re:For the airplane geeks...

[spaceyhackerlady]

Because they offer the best bang for the buck. Because pilots are trained to use them. Because they work. Because aviation is totally anal about "if it ain't broke, don't fix it". This is A Good Thing.

I'm learning to fly in Piper Cherokees, and I have a magnetic compass and gyroscopic heading indicator at my disposal. Both are accurate, but both have idiosyncrasies.

The magnetic compass is subject to errors when accelerating or decelerating on east/west courses. It also misbehaves when turning to/from north or south. The heading indicator slowly drifts as Earth rotates underneath it. On long flights you have to periodically re-set the heading indicator.

The pre-takeoff checklist includes setting the heading indicator to the magnetic compass, and verifying that both read correctly when you pull on to the runway. In the future Runway 01 (13 degrees) will become Runway 36 or Runway 02.

...laura

Re:I wonder

[icebike]

Sorry. But that is nonsense.

There are rednecks and fireworks everywhere in the USA on new years eve. Yet the massive bird death was strictly local.

The noise excuse is simply silly. It is not possible to create enough noise with a few big fireworks (or full sticks of dynamite) to kill bird over a 4 square mile area.

Can't be done, and if it could every city an town in the US would be littered with birds.

The most rational explanation is a large flock of birds, from somewhere possibly quite distant, were sucked aloft by a small un-noticed rural tornado or violent updraft and simply froze to death, and thawed upon landing.

Occam's razor applies to acts of nature.

Re:For the airplane geeks...

[trollertron3000]

Yup. The compass is one of the few instruments required in every aircraft in the US. Give me a tachometer, a compass, and an altimeter and I can navigate an airplane across the US.

GPS just recently came into the cockpit and the devices are expensive. People should realize that these are aviation instruments, so they need to be certified and are in turn expensive.

INS isn't in every aircraft simply because not every aircraft needs to be instrument-rated. Some people, like myself currently, only fly in VFR conditions. Removing these expensive instruments saves money, as you said.

Want to see a pilot bitch? Tell him he needs to buy something. For a great example of this search Google for the term "ADB-S requirement" and see the pilots moan about this new requirement. I should know, I'm one of them :D