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# Runway numbers

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I was reading this article regarding the completion of KFLLs new 8000 foot runway (  http://www.wsvn.com/story/26561291/new-fll-runway-opens-thursday-despite-residents-disapproval ).

I see that the runway's numbers have changed from 27L to 28L.

Is there a reason why many airports change the runway numbers in a similar fashion over the last few years?

Thanks

rob

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It's because the Earth's magnetic pole actually shifts a certain number of degrees every year, which in turn will change the magnetic heading a certain object, say, an 8,000 foot runway is actually on. So, instead of moving the entire runway some 10 degrees (from 270ish to 280ish), they just repaint the numbers.

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http://www.ngdc.noaa.gov/geomag/GeomagneticPoles.shtml

Another scenario for "illogical" numbering:

If there's three runways with the exactly same heading, say 273° (exactly parallel to each other) you'll get 27L, 27C, 27R. When you construct a fourth parallel runway, you'll have to change the number of one pair of runways to 28 as the designation scheme does not allow for anything other than "L", "R" or "C" to designate each parallel runway. So in the end, you'd end up with 27L, 27R and 28L and 28R.

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Bjoern, I noted that when KMIA added a new runway. What was 9r and 9L became: Runway 27, Runway 26R and 26L

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I noted that when KMIA added a new runway. What was 9r and 9L became: Runway 27, Runway 26R and 26L

You mean 9R and 9L became 10R and 10L, right?

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Sorry originally it was

Runway 27R and runway 27L

After completion of new runway

It is now

Runway 27

Runway 26L

Runway 27R

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