4:48pm

Mon January 10, 2011
Blog Of The Nation

Airport Runways Shift With The Magnetic North Pole

Many of us learn in science class that our compass points to the magnetic north pole rather than "true north." That's a fairly simple concept on paper, but it has very practical implications in the real world. The Tampa International Airport recently shut down its primary runway to rename it -- because its designation on a plane's compass has shifted. The Tampa Tribune reports:

The busiest runway will be re-designated 19R/1L on aviation charts. It's been 18R/36L, indicating its alignment along the 180-degree approach from the north and the 360-degree approach from the south.

Later this month, the airport's east parallel runway and the seldom used east-west runway will be closed to change signage to their new designations.

The paper explains that the Earth's magnetic north pole is gradually shifting about 40 miles a year. There's a video explainer and a history of the locations of the pole going back to 1831 at their website. Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.

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