How far up does the magnetic compass work? How do you update the
direction gyro?


David Lesher wrote:
writes:


Folks,


I am a sailor and not an airline pilot.


Recently I had a lunch with a 747 captain and the subject of
polar airline routes came up.


I maintained I didn't think any commercial routes went directly over
the pole or north of 80 N.Lat because the great circle routes from
say San Francisco to London didn't go that far north.



http://gc.kls2.com/ is great fun.

Note there's not just an ETOPS but also a search and rescue
issue -- survival time on the ice is mere minutes...unless
you're dressed for it...