flying from say, LAX

[dab69]

does anyone know the real reason when flying from LAX you first fly NORTH to Alaska, then across the Bering Strait, then South down the coast of the old USSR, etc.

seems this is terribly longer way to go, like they are afraid to go over the ocean.

perhaps there are specific routes they must take to avooid air collisions, but way
out of their way

does anyone know the real reason when flying from LAX you first fly NORTH to Alaska, then across the Bering Strait, then South down the coast of the old USSR, etc.

seems this is terribly longer way to go, like they are afraid to go over the ocean.

perhaps there are specific routes they must take to avooid air collisions, but way
out of their way

No, the route through Alaska is actually shorter than straight over Pacific Ocean. remember, earth is fatter in the middle... just like your waist :bounce:

It's called 'great circle' navigation

http://en.wikipedia.org/wiki/Great-circle_navigation

http://gc.kls2.com/

[Davey612]

does anyone know the real reason when flying from LAX you first fly NORTH to Alaska, then across the Bering Strait, then South down the coast of the old USSR, etc.

seems this is terribly longer way to go, like they are afraid to go over the ocean.

perhaps there are specific routes they must take to avooid air collisions, but way
out of their way

No, the route through Alaska is actually shorter than straight over Pacific Ocean. remember, earth is fatter in the middle... just like your waist :bounce:

Assuming Scott123 does understand that the Earth is round, the route he describes is actually not the shortest either. I believe the shortest line would actually go through Siberia down China. But nowadays, air routes are prescribed highways that all planes follow up. The described route is the general highway to Hong Kong or Taipei.

As an aside, anyone ever used SAS back when it had the polar route? The nonstop between Bangkok and Copenhagen? I read that it actually went close to the north pole.

[jimnbkk]

No, that's not the reason, Scott. Yes, the earth is in fact slightly pear shaped, but the reason planes fly that way is different.

They fly the shortest route!! It's called a Great Circle. (Sorry about this next bit) A great circle is the line traced on the earth's surface by a plane connecting the two points (LAX and BKK for example) and passing through the center of the earth. It's the shortest distance.

You can prove it to yourself by taking a piece of string and stretching it between the same points, then let it slip to a great circle route, and you'll have string left over.

Very good explanations. As a Boeing employee, I have had to explain this to people many times to people looking at a Airline route map and ask me "why do they take curved routes instead of straight?". The answer being of course, because the map is flat, but the earth is round, and a route on a map that appears "straight" is actually longer. Often people incorrectly think the planes follow the great-circle routes for safety reasons (proximity to land should an emergency happen), but this is incorrect. In the past, twin engine jets have has some limits as to distance from land, but these restrictions have pretty much been lifted as the safety of long overseas flights on twin engine planes such as the 777 have been proven to be the same as the 3 and 4 engine jets.

... is flat? What's the explanation then?