it's just spherical geometry...

March 10, 2005 1:21 PM

Great Circle Mapper"Never again will I sigh and stammer when presented with the question, "Why does my flight from Chicago to Hong Kong fly over goddamn Siberia?" (via Salon registration or viewing short ad required)
posted by quonsar (30 comments total)

does this mean our omnipotent q is planning to take a trip? (and is trying to find a route where he wouldn't face surface-to-air missiles?)
posted by wendell at 2:00 PM on March 10, 2005

I'm trying to make a flight path that goes right over the North Pole.

Chicago to Calcutta comes pretty close.
posted by jefbla at 2:18 PM on March 10, 2005

Hey, if you crash in eastern Siberia you might get rescued by Chukchis. And eaten.
posted by davy at 2:18 PM on March 10, 2005

While you're at it: the FAA's pdf library of airport diagrams.
posted by carter at 2:21 PM on March 10, 2005

Having flown the Chicago to Hong Kong route a few times Siberia is not a place that I would ever want to see closer than 30000 feet above.
posted by mss at 2:22 PM on March 10, 2005

I'm trying to make a flight path that goes right over the North Pole.

Why not the South Pole? Do they do that?
posted by davy at 2:23 PM on March 10, 2005

For the South Pole - Buenos Aires to Perth comes soooo close.

Try:
EZE-PER
posted by redteam at 2:27 PM on March 10, 2005

From Calcutta to Yucatan goes over the North Pole too. But Calcutta to Sntiago de Chile goes over Natal!

And thanks, redteam.
posted by davy at 2:30 PM on March 10, 2005

Not something I've ever had to factor in, anyway.
posted by tss at 2:39 PM on March 10, 2005

My pleasure. Santiago de Chile to Perth goes pretty close, too.

Hmmm ... before posting the above sentence, I thought a little more about this ... I thought about some point between the two and Cordoba came to mind. Goes right over the South Pole. But there is no way that Cordoba is EVER going to have a direct flight to Perth.

COR-PER
posted by redteam at 2:44 PM on March 10, 2005

Yep, COR-PER pretty much nails it.

If you continue from Perth and go to Cairo, then back to Cordoba, the map takes an interesting shape.
posted by jefbla at 2:54 PM on March 10, 2005

While I can still use passes, I flew around the world 01/10/05-01/22/05, visiting my brother in Perth and relatives in London.
posted by copmuter at 3:13 PM on March 10, 2005

The great circle of life has begun.. We will not all get there at the same time.
posted by LouReedsSon at 3:48 PM on March 10, 2005

Almost useful, but still awesome. Thanks.
posted by DrJohnEvans at 3:55 PM on March 10, 2005

Making patterns is fun!
posted by rocket88 at 4:03 PM on March 10, 2005

Hee, a frequent-flyer-fanatic friend of mine just mailed me a link to that site to show me the path he's flying next week, for just US$2800 thanks to a currency-exchange decmal-place slip-up at Travelocity: Papeete -> Santiago -> Sydney -> Santiago -> Madrid -> Santiago -> Lima -> LAX -> Papeete.
posted by nicwolff at 4:12 PM on March 10, 2005

Rocket88 - thanks for the laugh!
posted by nostrada at 4:16 PM on March 10, 2005

Hey nicwolff ... you sure it was an error? I flew to many more places than that (though probably the same distance) for like $2600 on a OneWorld Round-the-World ticket in 2003 and 2004.

Folks, RTW tickets are so awesome.
posted by redteam at 4:22 PM on March 10, 2005

Making patterns is fun!

Yes, but that LAX-Churchill, Manitoba run kills me everytime I fly it.
posted by sleslie at 4:23 PM on March 10, 2005

Continental Airlines flies from Hong Kong to New York over the North Pole.

Saves a few hours on direct flights.
posted by bwg at 5:16 PM on March 10, 2005

Huh. How strange. Just last week I used that link to explain to my family why one of us would fly over the arctic circle on their way from SFO to FRA. Well, I tried to explain, but it didn't stick very well. One thought it was due to the rotation of the earth, another just didn't believe it ...
posted by intermod at 5:58 PM on March 10, 2005

intermod: It might help in 3D. If you can see them in person, get a globe and some string and show that the great circle route is the shortest.
posted by tss at 8:31 PM on March 10, 2005

Cool. I'll always remember a non-stop flight I took as a kid from San Francisco to London. I got invited to the cockpit and the first thing I thought when I looked out the window was, "why the heck are we flying over all these icebergs?"

(A tickle in my brain is telling me that I remember reading once that Billy Mitchell was a one of the first proponents of, "it's quicker to fly up than it is to fly across."
posted by Cyrano at 9:04 PM on March 10, 2005

jefbla, new orleans to calcutta's even closer (MSY-CCU).
posted by Igor XA at 10:01 PM on March 10, 2005

'fly up than to fly across'?
posted by quaeler at 3:04 AM on March 11, 2005

jefbla, Halifax, NS to Beijing, PRC. YHZ-BJS
posted by Kirth Gerson at 3:19 AM on March 11, 2005

Note: You rarely fly a true great circle, even on long trips. Why? Two factors:

1) Winds. If flying an extra 400 miles puts you into a favorable jet stream (or gets you out of an unfavorable one), then it is more than worth doing so, in terms of time and fuel. This is very common on JFK-HKG routes, which always assume that they'll be flying long reroutes to avoid the jet stream, and almost always do -- and arrive a couple of hours early on the rare days when they don't. The converse case is ORD-LHR, which is normally booked as an 7:45 hour flight, but I've flown in it 6 when the jet stream was just right, making an 1000 arrival at 0815. ORD-LHR almost always arrives a little early, but that was a bit much.

2) ETOPS: Extended Twin-engine Operations. By rule, twin engined jets can't fly more than one hour away from a suitable landing strip, as measured by time it takes to fly there with one engine. This makes overseas flights tough. The rule is there because twinjets only have one spare engine. The rule is also why the A340 and 747 are still around -- airlines *vastly* prefer twinjets, which are much cheaper to operate, but sometimes, the deviation from the GC route is too much. SYD-LAX is the classic example, see Qantas' fleet of 747-400 and 747-400LRs. (Aside, the A380 will also have four engines, but that's as much due to mass as ETOPS considerations.)

Moderns jets extend this, via ETOPS, by proving that the engines are better, and by having extra gear for power generation. Most as ETOPS-120, which is two hours away, some are ETOPS-180, and Boeing is trying to get the 777-300ER and 777-200LR rated to ETOPS-205.

These planes can (and do) fly overseas, but in the case some routes, they fly routes that deviate greatly from the ideal great circle route in order to stay within the ETOPS mandate flight time to a diversion airport. ETOPS-205 would open up almost all of the Pacific, and effectively remove the ETOPS penalty.
posted by eriko at 4:29 AM on March 11, 2005

And, hey, I just scrolled down. You can put ETOPS restrictions in (and I misremembered ETOPS-207).

So, for "real life" routes, assume ETOPS-120 or ETOPS-180 when making your uber-routes.

(And you know know why planes like the 727, DC-10, and L-1011 had three engines....)
posted by eriko at 4:32 AM on March 11, 2005

I have never been served peanuts on the Halifax-Beijing direct.
posted by DrJohnEvans at 9:42 AM on March 11, 2005

Hey! Stop dissing Siberia!
posted by thirteenkiller at 10:03 AM on March 11, 2005