by Captain Joe
What is the meaning behind the numbers and letters on the runway?
I´m sure many of you have seen my approach and landing videos here on Youtube, and you might have wondered, what is that number and letter you see on the runway just prior touchdown.
Let´s first talk about the number.
We´re gonna have to cover some basic navigation first.
As we look at our planet earth we have the geometric north and south pole in each hemisphere, marking the top and bottom of the planet. But there´s no instrument besides GPS which could guide us towards these poles.
But the planet has it´s own magnetic field surrounding the earth, creating the magnetic north and south pole which are slightly off of the geometric poles.
Now you´ve all seen a compass, and you know that the needle always points towards magnetic north.
Now let´s look at this runway here, you can see the numbers 08, let´s imagine you would draw a line all the way from the magnetic north pole down until it crosses the runway center line. You would see that the two lines create an opening angle of 080 degrees. Meaning the runway center line is 080 degrees relative to the magnetic north pole.
So why is there only a 08 on the runway? There are two reasons for that.
Let´s say the magnetic heading of the runway would be 084. Then it would be rounded off to the nearest tenth, so in this case, 080, leaving out the last zero, you have runway “Zero eight”.
But if you would name the runway “zero eight zero” could lead to misinterpretation as given headings are spelled the same way, like fly heading 120 for example.
Now as you sit in your plan on the runway, in this example runway 05 in Madeira you know you know your plane nose is pointing 050 degrees, so heading northeast, and your airplane tail is pointing + 180 degrees into the opposite direction, so the reciprocal runway should be? Yes, runway “two tree”.