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Why Airports Rename Runways When the Magnetic Poles Move (wired.com)
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.
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.
Moderating "-1, Disagree" is simple censorship. Have the guts to post your opinion.
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.
E pluribus unum
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, 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, 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.
The general idea is to REDUCE the number of things that a person flying with passengers in a can in the air has to think about in an emergency, under stress in low visibility conditions when the aircraft has lost GPS or other critical systems and the baby in the back seat is screaming because of ear pain from required rapid altitude changes and the tower's radio system is down ... but the magnetic compass is working as always, and the sectional chart has a nice big number that MATCHES THE COMPASS. Because you're going to land or die in the next 60 seconds. All of these things are designed around worst-case, high-stress possibilities (which almost never occur, but sometimes do).
Don't disappoint your bird dog. Go to the range.
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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