Hey guys!
For a while, before I knew much about aviation, I always wondered why runway numbers at every airport worldwide didn’t exceed the number, 36. I thought I’d write this topic just to explain it to those who maybe didn’t know why, or didn’t even notice!
So, when looking the pictures below, which I’ve taken from numerous airports worldwide, we see none of the runway numbers pass the physical number 36.
KJFK, all runways.
Source
London Heathrow.
Source
Sydney International.
Source
Miami Intl’.
Source
Now, you may be asking yourself why don’t the runways exceed the number 36?
The answer, simple. The numbering of runways are based on their magnetic bearing, or what heading the aircraft is at, at runway heading!
The more complex answer, can be found below :)
Consider a plane flying toward the runway on final approach in a day without any wind. Divide its magnetic heading by 10, round it to the nearest whole number and you’ll usually get the runway number. For example, if the magnetic heading is 345° then 345/10=34,5, so the runway number will be 35 which will be a runway used for landings (and takeoffs) to the north.
Opposite ends of the same runway have different numbers, 18 (which represents 180 degrees) apart. A runway with 35 for landings to the north will have runway 17 for landings to the south. Even though these are the same strip of concrete, they are treated as separate runways by pilots and controllers.
If there are two airports near one another with runways at the same angle, sometimes one of the airports will add or subtract one from the runway number to help planes differentiate between the airports.
Occasionally a runway number will change when the magnetic declination angle changes in such amount, making the runway magnetic bearing divided by 10 and rounded to the nearest whole number increase or decrease.
Some runways in areas of large magnetic declination use true instead of magnetic headings for the runway numbers. This is not unusual in northern Canada and Greenland.
When there is more than one parallel runway at an airport, L, R, or C may be appended to the runway number for Left, Right, or Center. These are based on the approach direction, so, for example, the runway 35L would be called 17R from the opposite direction.
I already knew about this.
Cool! But I don’t need to know.
This is a duplicate
Very likely, I’m sorry in advance.
I hope you guys enjoyed this little piece of (i hope) cool information about runway numbering, and maybe even learned a thing or two!
Kev :)
