As the Crow files or not ?

[Deano]

Hi

Having flown to Florida twice in the last few years from the UK I wondered why the flight path follows the the lie of the land such as Greenland and US eastern seaboard as opposed to flying directly over the Atlantic Ocean as the crow flies ?

Surely it would be both quicker and more efficent to do the latter ?

[Falcon]

A staight line on a shpere is slightly different and would curve slightly on a flat map. The reason your flight hugs the land is likely to be because you have two engines. There is a requirement to keep 45 mins from and alternate airfield. When I bump into one of our former long haul Captains I'll get him to tell me the shortest ideal route.

[EyesSkyward]

Having flown to Florida twice in the last few years from the UK I wondered why the flight path follows the the lie of the land such as Greenland and US eastern seaboard as opposed to flying directly over the Atlantic Ocean as the crow flies ?



Yeah, that's one of the quirks of spherical geometry: "directly over the Atlantic Ocean" is actually not the shortest distance. As Falcon was saying, the flat maps we're used to looking at are distorted "projections" of the globe, so you can't apply the normal Euclidian rules.

To get the real shortest distance, imagine wrapping a big rubber band around the earth in such a way that it divides the globe in two equal halves, yet covers both airports. Then just follow the rubber band!

I've attached a picture to show what that looks like between Orlando and Heathrow. As you can see, by happenstance, it tends to hug the coast fairly closely anyway. Now the rules concerning twin-engine planes will require some adjustment to that path, again as Falcon pointed out. But it's not really that much, relatively speaking, since you're already curving that way a bit anyway.

- Jeff

[Falcon]

Nice one, could you show two more lines? One from Edinburgh to Orlando, as Many flights head North before making the pond jump. The second one over the North pole, I'm keen to see what they look like.

[Lynda]

That is really interesting! Every one of our many Orlando flights have flown over Ireland, The last few years we have flown Virgin on a 747 and they appear to fly a more direct route but still over Ireland. The US flights we have been on have flown over Greenland and Canada but of course these have not been direct flights.

[Falcon]

Shanon Airport used to make a fortune selling aviation fuel cheaper then England. Trans Atlantic flights used to carry enough fuel to Ireland, fill theirs boots and save money.

[EyesSkyward]

Shanon Airport used to make a fortune selling aviation fuel cheaper then England. Trans Atlantic flights used to carry enough fuel to Ireland, fill theirs boots and save money.


I landed in Shannon once after a looooong delay in Chicago. We were supposed to be flying to London, but the crew had reached their duty time limit and we had to swap out crews for the last little jump in order to stay legal.

Oh, and you can plot any Great Circle route yourself using this fine web site (http://gc.kls2.com/). :thumbsup:

- Jeff

[Falcon]

Thanks for that.