Why is the marking on the runway written as (9/27) Telluride (KTEX), Colorado, USA. whereas the direction is 284 degrees? Shouldn't it be (10/28) instead?

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    $\begingroup$ Welcome to Av.SE! $\endgroup$
    – Ralph J
    Mar 25, 2019 at 12:46

1 Answer 1


That direction (284) is the true heading, but runways are numbered according to the magnetic heading.

Runways are usually numbered according to their direction, more precisely called runway magnetic bearing or QFU (see Q codes). (How are runways numbered?)


276 magnetic, 285 true
096 magnetic, 105 true

While 276 should be rounded to runway 28, it could be a recent change that the magnetic heading changed to 276 from say <275. There is a process to go through, so a recent change in magnetic variation does not mean the renumbering will swiftly follow.

Every five years, the FAA reevaluates shifts in the pole—its magnetic variation—and makes changes to runways and flight procedures as needed. (How do airports determine when they should change their runway numbers?)

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    $\begingroup$ For the curious, the NOAA has historical magnetic declination data. The map does indeed show that the magnetic declination around Telluride has shifted by about 1° over the past ten years, which lends credence to the idea that the magnetic heading used to be less than 275°. $\endgroup$ Mar 25, 2019 at 15:24
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    $\begingroup$ Yeah, the magnetic North Pole has actually moved by a surprising large amount over the last few decades. It used to wander around relatively slowly over Northern Canada, but it's been quickly accelerating straight towards Russia over the last few decades. It was over Northern Canada in 1994 and is now almost halfway to Russia. $\endgroup$
    – reirab
    Mar 25, 2019 at 18:14
  • $\begingroup$ @reirab I smell collusion. $\endgroup$
    – hobbs
    Mar 25, 2019 at 22:31
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    $\begingroup$ @hobbs Yeah, it started in the Soviet era. Obvious Communist plot to steal the North Pole from NATO countries. $\endgroup$
    – reirab
    Mar 25, 2019 at 23:49

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