Why Do Intercontinental Flights Head North?

Have you have ever been on a long flight and noticed that the path of the airplane seems to be going out of the way toward the North Pole instead of directly to your destination? That’s because it is, and there is a very simple reason for it. 
Despite what many people believe, the answer actually has nothing to do with safety. The real answer is because going north may actually provide a shorter route. This is called Great Circle Navigation. Because of the curvature of the Earth, the shortest route between two locations may appear much longer on a flat map. For a better understanding of this phenomenon, let’s use STK to take a trip to one of our international locations, Singapore! 
STK can be used to model some possible routes from New York to Singapore. The map below shows two possible routes, a typical route (blue) that flies north and a route that appears more direct on a flat map (yellow).

In this image, the yellow route looks much more direct and the blue one seems out of the way. If you saw this map on your flight, you might be stuck staring at your screen wondering why your pilot decided to take an impromptu visit to the North Pole. However, in reality the blue route is significantly shorter. This can at least partially be seen in the picture of the globe window below. 

In this image, the two routes at least look roughly similar in distance. But let’s check the actual values computed by STK. 
This can be found in the Report and Graph Manager. The Scalar Calculations data provider presents the distance calculated along the ground track of the aircraft. Here are the values presented for the two routes: 


Notice the time difference between the two routes. The northern route saves you a full 3 hours of vacation time. That’s a whole extra trip to the mall, thanks to your pilot.  

And who doesn’t like shopping? 

Note: The STK scenario used to create the images and report in this blog is located here.


Systems Tool Kit (STK)

Modeling and simulation software for digital mission engineering and systems analysis.