Posted on 01/06/2011 8:52:44 AM PST by TaraP
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.
The closure of the west parallel runway will result in more activity on the east parallel runway and more noise for residential areas of South Tampa.
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 Federal Aviation Administration required the runway designation change to account for what a National Geographic News report described as a gradual shift of the Earth's magnetic pole at nearly 40 miles a year toward Russia because of magnetic changes in the core of the planet.
I could be wrong, but I beleive the charts are oriented to True North, not mag.
And I remember when Newark and LaGuadia were walk-to-your-plane airports... :)
Used to be a lot of airports in the early ‘60s like that, but those two must have been before that.
Published routes on other charts, such as Instrument Approach Plates and Low/High Altitude Enroute charts are always given relative to magnetic north. Radials of VORs, a type of navigational aid, are based on magnetic north. When the winds are reported via a recording to a pilot at an airport (ATIS), they're converted to magnetic north. And the runways at airports are labeled based on magnetic north. The annual change of magnetic variation for a particular airport is listed on its airport diagram.
Here's an example (link from airnav.com): http://204.108.4.16/d-tpp/1013/00237AD.PDF
At the left side of that chart are the variation arrows and a note explaining that the annual rate of change is 0.1 degree west.
The compass knows where north is. It's ancient, but it works and its flaws are taught to pilots. It's also a required instrument for all IFR flights, even on airliners.
Makes me wonder how many elves Santa has assigned to keep moving the candy cane North Pole marker . . .
This is actually not that unusual. For example, Runway 14 at Farmmingdale NY (KFRG) is 146°, so it ought to be called Runway 15. The airport was started in 1927, presumably when the runway was first designated the magnetic bearing was less than 145°, hense the designation Runway 14. If the drift continues, they will probably redesigate it as Runway 15.
The importance is that winds are always given in magnetic bearing as a “from” number, for example from the NorthWest at 330°. Since you want to land into a direct headwind, if the winds are from 330° you will want to land on a heading of 330° (Runway 33) or as close to that number as possible; so if you have a choice of Runway 29 and Runway 35, then other things being equal you will want to land on Runway 35.
Not a very good excuse, IMHO.
In the unlikely case that a pilot is using an old-fashioned compass instead of GPS for navigation, and if he hasn't already corrected for magnetic deviation long before the runways can appear in his visual horizon, then it seems to me that he isn't actually going to get to the destination in question -- in which case the FAA's "favor" to him becomes entirely a moot point!
40 miles a year?????
Would that possibly be correct? In 5 years, that would be 200 miles!!
Seems like alot.
huh? ping
Aircraft basic avionics use a magnetic compass. The magnetic deviation and magnetic variation are drastically different across the United States, so magnetic directions come straight off the avionics, while geographic directions must be calculated after consulting a chart.
Runways are oriented for meteorological and topographic convenience; they are then named according to the resulting magnetic direction.
A mind like a steel trap.
By meteorolgical, I assume you mean that they line up the runways based on prevailing wind conditions.
Because your iPhone is a computer, it has a GPS, and it does the calculation for you.
A well equipped aircraft can do the same thing, if the pilot wants it to.
Still, a simple compass doesn't break easily, and doesn't require electricity.
KISS.
Learn it. Live it. Love it.
Because runway designation protocol was established before the iPhone hit the market.
Correct ... main runways tend to be oriented according to prevailing winds, with modifications based on lay-of-the-land. Crosswind runways are almost never actually perpendicular to the mains. The Army Air Corps loved to build triangular airfields, and some modern airports (Denver, for example) are quite complicated.
Very likely. ;-)
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