Those huge white numbers at the runway’s start are not chosen at random. They have actual meaning and purpose. When assigning runway numbers, a logical and straightforward system is used. But do you know what these numbers were based on?
Airport runway numbers are not sequential; compass bearings determine them. Runway 9 is 90 degrees, while runway 27 is 270 degrees.
What is the Significance of Runway Numbers?
The runway numbers actually indicate where the runway is pointing to magnetic the north. Those who have listened to air traffic control conversations will be familiar with the fact that pilots are instructed to fly on three-digit headings, which refer to the direction’s compass relative to true north.
A heading of 180, for example, would represent following a path 180 degrees from true north – in other words, directly south. Similarly, runways are numbered using similar logic, albeit with a slight variation. Their heading in dec degrees explicitly identifies them. This measurement’s heading is divided by ten. (Source: Pilot Institute)
What Do the Letters on the Runway Mean?
What happens when an airport has two parallel runways on the same compass bearing? Having multiple runways with the same designation would be highly confusing, not to mention dangerous. Fortunately, there is a solution to this conundrum. In the case of two parallel runways, these landing strips will be labeled L or R.
These letters indicate whether the runway is on the pair’s left or right side. For example, the runways at London Heathrow are 09L/27R and 09R/27L. When a third runway is added, the middle strip is designated with a C, which stands for center. Three of Frankfurt’s four runways are parallel, with the middle numbered 07C/25C.
Some very large airports have four or more parallel runways. In these cases, the C designation cannot distinguish all four landing strips. As a result, airports will occasionally renumber a pair of runways by a factor of one in order to avoid confusion.
Although Los Angeles International Airport has four parallel runways, they are numbered in pairs. These are 6L/24R and 6R/24L, as well as 7L/25R and 7R/25L. Finally, Honolulu International Airport in Hawaii has runways 4W/22W and 8W/26W with a W suffix. This indicates to pilots that it is a water-based runway intended for use by seaplanes. (Source: Pilot Institute)
What Does Runway Zero Mean?
There should be no runways with the numbers 0 or 00. Any runway that faces magnetic north is normally designated as 36 or 360 degrees. This will also match the headings read out by ATC and the pilot.
When an airplane is flying north, the heading is always three-six-zero, never zero zero zero degrees. This is reflected in the naming convention of the runway numbers.
Runway numbers are always given as individual numbers combined together. Each number is read separately to ensure no confusion. No whole 10’s or 100s are used when ATC or pilots mention runways.
Runway numbers actually correspond to the runway’s magnetic direction in degrees. If there are parallel runways, they are further deconflicted with letters. Simply add a zero to the end of the numbers to determine where they point. (Source: Pilot Institute)
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