The puzzles of international travel...
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It might also have something to do with flight paths... remember that there are lots of planes in the sky, not just yours, and it is good if they don't run into each other, or even get too close. :) I imagine that with enough planes going in enough different directions, some of the paths they take could end up looking very strange indeed. -- Diane C "Doubt is not a pleasant condition, but certainty is an absurd one." (Voltaire)
I had the opportunity to visit a FAA Enroute Facility last year and there ARE a lot of planes up in the air during the day. Each controller is assigned a 3 dimensional area of airspace and is responsible for each plane as it enters his area (not exactly shaped as a cube) until it exits his area. As the planes go from area to area they are handed off from one controller to another controller. Sample Enroute Air Traffic Display[^] - seeing the displays updating in real time was way cool! There are 20 of these centers in the US. There are other facilities that take care of traffic management when planes take off and get close to their final destinations. GPS navigation is still being developed, so there are still ground stations (beacons) that planes use to make sure they stay on course. I suspect that may be another reason the overseas planes stay close to land when ever possible. As far as I know they do not have navigational beacons in the middle of the ocean (not counting islands). Steve
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A couple of weeks ago I posted from Singapore and mentioned that I'd spent 18 hours flying from Los Angeles to Singapore. Someone questioned that time. Flight time was actually 18 and a half hours* and the route taken puzzles me a trifle. If one looks at a map one sees that Singapore is west of LA and a few degrees north of the equator (that is to say, southwest of LA). The route we took was as follows (partly taken from the map display on board the plane, partly from observation - I had a window seat on the right hand side of the plane). Out of LA, westward over the Pacific Ocean. I was surprised 15 minutes into the flight to see land off to the right. We were travelling northward. An hour into the flight I could see San Francisco. Some hours later the map display indicated we were close to Alaska and indeed the horizon looked like pre-dawn (no sun but lots of pink). This continued for some hours as the map indicated we had passed northward of the Aleutian Islands and faded as we turned southward again. At about the time the map indicated we were over Japan (having passed by Siberia and Northern China) all I could see below were clouds brightly lit from below - for some hundreds of miles. Thence across the Philippines (my destination) and continuing south westwards to Singapore. Thus, 18 and a half hours later, we landed at Changi Airport and doubled back to Manila. I understand that paper maps are a two dimensional representation of a three dimensional space and that aeronautical navigation involves great circles but that route seems to me to be somewhat out of the way even allowing for great circle navigation. Indeed, it felt almost as if the pilot didn't want to be more than 50 miles from land at any one time :) Anyone understand aeronautical navigation enough to comment? *I flew Singapore Airlines - it was so good I fear I've been forever spoiled for travel by any other airline. We were on an Airbus rather than a 747. It's really cool to have video on demand in economy - not to mention economy seating that's almost as good as business seating on United Airlines. Thankfully Singapore Airlines is a member of the Star Alliance so my frequent flyer points are added to my normal United account. Rob Manderson I'm working on a version for Visual Lisp++
Francisco gives a correct explanation - a straight line on a flat map is not the shortest route. This page gives an explanation ( http://plus.maths.org/issue7/features/greatcircles/[^] ). Also, if you look at the map shown on this page, you can see that a flight from London to Alaska would go almost directly over the North Pole, but when you think about it in terms of Latitude, it doesn't make much sense since London and Alaska are both at a lower latitude than the North pole. ----------------------------------------------------- Bush To Iraqi Militants: 'Please Stop Bringing It On' - The Onion "Moore's prominent presence in the news brings to light some serious questions, such as 'Can't he at least try to look presentable?'" - The Onion