Thursday, January 17, 2019 Uncategorized

Did you know that almost every year there’s an airport somewhere on the planet that needs to rename its runways due to changes in the earth’s magnetic field?

In 2013, The Calgary Airport Authority renumbered five runways – three at YYC Calgary International Airport and two at Springbank Airport (YBW). At that time L or R were added to YYC’s runways (for left and right) to prepare for the opening of the parallel runway in 2014, ensuring pilots started to align themselves with the correct runway.

Runway numbering is based on magnetic direction, and airports around the world number/name their runways using this one simple international logic system so that there is a consistent means for pilots to line the aircraft up for arrivals and departures.

YYC’s parallel runways are orientated to a true north heading, or compass direction, of 360 degrees north or 180 degrees south. Our current magnetic declination is 13.5 degrees east - meaning that there is a 13.5 degree difference between true north versus magnetic north.

Here is the calculation for how runway numbering is determined: 360° - 13° = 347°. Then round up to 350 and drop the zero to get the number 35 for the northbound runways and the 180 degree reciprocal of 17 for the southbound runways.

As a comparison, in 2000, Calgary was sitting at 17 degrees east declination. By 2013 that had changed by 15 degrees; renaming meant all new signage had to be procured and installed, as well as repainting the runway numbers. Additionally, all of the publications and drawings had to be updated.

Due to the unpredictability of the North Pole, it is unknown when runway renaming will be needed again.

Question: By how many kilometres does the north magnetic pole move every year? Let us know in the comment section below!