Single Physical Runways

A runway designator consists of a two-digit number, which is the whole number nearest to one tenth of the magnetic North when viewed from the direction of approach. For example, if the azimuth of the centreline is 153 then the runway designator will be 15. When this rule results in a single digit number then the designator is preceded by a zero (e.g. if the runway cenreline azimuth is 82, then the designator will be 08). North-oriented runways are designated 36 (not 00). In simple words, the runway designator represents the heading used for taking off or landing at the runway.

If the runway is used in both directions, then each of them receives its own designator. This means that although there is one physical surface used for take-offs and landings, it is treated as two runways. The difference between the numbers is 18, e.g. if one of the runways is 12 then the other will be 30.