Given that runways are labelled by magnetic heading. What happens in airports that have more than one in the same direction?

How are they labelled?

Are there any such airports?

  • 2
    $\begingroup$ I'd guess that the great majority of airports with more than two runways have at least two parallel. Not all, since triangular arrangements are quite common (especially at former WWII-era air bases). Probably almost all airports with more than three runways have at least two parallel. $\endgroup$ Commented Aug 16, 2015 at 11:25
  • 1
    $\begingroup$ Most major commercial airports have at least two parallel runways, even -- so this configuration is far more common than the OP envisions. $\endgroup$ Commented Aug 16, 2015 at 16:40
  • $\begingroup$ Voting to reopen this, as the marked duplicate question does not cover the case of more than 3 parallel runways $\endgroup$ Commented Jul 23, 2019 at 17:43
  • $\begingroup$ @J.Hougaard - last paragraph of this answer covers 3 runways and one of the comments covers 4-6 runways. (I know... comments can be deleted.) $\endgroup$
    – FreeMan
    Commented Jul 23, 2019 at 19:53

1 Answer 1


Left, right and centre.

For example, Heathrow has 27 left (27L) and right and 09 left (09L) and right.

See here for the airfield chart.

You can see the numbers close to the end of the runways.

Here's an example for an airfield with a 34 left runway.

enter image description here

If there are more than three runways more or less parallel, one or more runway numbers will be shifted by 10 degrees, e.g. 08L, 08C, 08R, 09R.

From the Wikipedia article on runway numbering:

At large airports with four or more parallel runways (for example, at Los Angeles, Detroit Metropolitan Wayne County, Hartsfield-Jackson Atlanta, Denver, Dallas-Fort Worth and Orlando) some runway identifiers are shifted by 10 degrees to avoid the ambiguity that would result with more than three parallel runways.

For example, in Los Angeles, this system results in runways 6L, 6R, 7L, and 7R, even though all four runways are actually parallel (approximately 69 degrees). At Dallas/Fort Worth International Airport, there are five parallel runways, named 17L, 17C, 17R, 18L, and 18R, all oriented at a heading of 175.4 degrees.

Occasionally, an airport with only 3 parallel runways may use different runway identifiers, for example when a third parallel runway was opened at Phoenix Sky Harbor International Airport in 2000 to the south of existing 8R/26L, rather than confusingly becoming the "new" 8R/26L it was instead designated 7R/25L, with the former 8R/26L becoming 7L/25R and 8L/26R becoming 8/26.

  • 4
    $\begingroup$ And left and right are from the point of view of a plane coming in to land: a runway that's labelled 09L at one end will be 27R at the other. Also, there might be "missing" runways because something was decommissioned. Chicago O'Hare, for example, has runways 10L/28R and 10C/28C but no 10R/28L. $\endgroup$ Commented Aug 16, 2015 at 12:05
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    $\begingroup$ Note that only the runway number is different in the case of more than 3 parallels. The runways themselves are not actually shifted 10 degrees. Also, usually in the case of 4 runways, you'll have R+L of one number and R+L of the other. Atlanta is an example of 5, with 08R/L, 09R/L, and 10. $\endgroup$
    – reirab
    Commented Aug 16, 2015 at 19:34
  • $\begingroup$ @DavidRicherby - in O'Hare's case the southernmost runway has been labelled C because 10R/28L was planned but never built. They finally got around to it in October 2015. $\endgroup$
    – KeithS
    Commented Aug 12, 2016 at 17:40

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