Runway names determine where a plane lands at an airport, especially if there is more than one runway. But, why are they named after numbers and what do these numbers mean? To work out a runway name, Maths is the main tool. This is easy for pilots as they taught simple maths like this problem in flight school. The mathematical tool for runway names is called bearings. These determine where a vehicle is moving from the north, and its due course.
The rules of bearings
Here are the main rules for using bearings:
- Bearings always start from North and go clockwise, e.g. East would be 90 degrees.
- Bearings always have three digits in their names, but airports shorten this down to the first two. For instance, One of London Heathrow’s runways is called 09, but its bearing is 090 because it must have three digits.
- Every runway has 2 names. If we look at a small airport like the one on the small island of St. Helena, its one runway has 2 names, 20 and 02. This is because if you are approaching the airport from the south-west, then you are on a bearing of 200 degrees, and if you are approaching from the north-east then you are on a bearing of 20 degrees.
- If a runway is straight, its two names will have a mathematical difference of 180 degrees e.g. 200 – 180 = 20.
Bearings determine the heading of the plane on the autopilot, so if you were to put in “Heading 270” to the computer, your aircraft would head direct west until you told it not to.
The final stage of a runway name
Finally, next to the bearing number of a runway is one of three letters, L, C or R. These stand for Left, Center and Right. This means that when you approach the airport, you are flying to the Runway on the left or right. In Heathrow’s case it has 4 runway names: 27L, 09R, 27R and 09L. When you approach 27L, it will be the left runway out of the two. In some cases, airports have three runways (soon to be Heathrow) so the middle runway bearing is followed by C, standing for the center.
So next time you are on a plane and listening into the flight deck when you hear ATC say “Speedbird 002 approach runway 27 right,” You can do what avgeeks do best: Explain avgeek stuff to your non-avgeek friends whilst they pretend to act interested.
cires.colorado.edu (Cover Image)