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Aviatorjoe
21st Oct 2011, 14:10
Hello :)

I started my ATPL school 3 weeks ago and the first assignment for G-Nav was given to me yesterday. I have to calculate them for monday, but i'm not quite sure how to do it. I can't seem to find answers in the book for my particular question.

I have to give the shortest distance in nautical miles for the given coordinates

62' 00N 093' 00E and 62' 00N 087'00W

I'm able to figure it out when its the same median but not the other way around.

Hope anybody wanna help a aspiring pilot.


Best Regards

Joe

RichardH
21st Oct 2011, 14:48
Yes this often gets students. Check add up the 2 LONGITUDES if they equal 180 then the second position is on the anti-meridian! So the GC distance will be from N62 north up the 093E meridian to the north pole then south down the 087W meridian to N62. If in doubt have a look on a globe.

N62 to N90 = 28 change latitude + N90 to N62 = 28 change latitude so total latitude change of 56 * 60 (1 degree of latitude = 60nm) = 3360 nm is the shortest great circle distance.

The rhumb line distance would be 180 * 60 * cos62 = 5070 nm, which explains many long-haul flights routing via the polar regions.

Aviatorjoe
21st Oct 2011, 15:46
Thanks a lot for the reply. Helped finish my homework:ok: