Why do aircraft pilots follow so much longer routes?

[zed]

sorry forgot about this, after a bit more digging
http://www.aspire-green.com/mediapub/docs/strategic_plan_2011.pdf
see section 3.3.1 etc

Yes they do try to do the most efficient route possible.

actually they dont, up until this initiative ~2008 aircraft would fly between weighpoints(sp) along flightpaths, eg that image above looks like they are, i.e. the plane hits the hebrides (I think) and does a turn

http://www.greenaironline.com/news.php?viewStory=292

The first demonstration occurred last month in which an Air New Zealand Boeing 777 flight from Auckland to Los Angeles managed to save an estimated 4,500 litres of fuel

4500 liters, how many passangers is that worth? a couple prolly at least.

when u think about it, It seems batshit crazy it took them until the fuel crisis in 2008 before they started actually implmenting this

 

[KimB]

when u think about it, It seems batshit crazy it took them until the fuel crisis in 2008 before they started actually implmenting this

Well, my guess is that for a long time, they simply followed the shortest distance path. It's only been in relatively recent years that computer power and our measurements of weather patterns have been up to the point where we could actually perform more fine-grained optimization, and it is entirely understandable to me that airlines would be a bit slow to adopt newer flight planning strategies.

 

[zed]

Well, my guess is that for a long time, they simply followed the shortest distance path.

they never did, what they did was fly from waypoint to waypoint, flightpath corridoor (see the map above over the UK) now the shortest path between 2 points on a globe is a curve right? but u will see there after it takes off, it flys ~1000km straight ahead then does a ~5 degree turn to the left (just above the hebridis) and then flys straight ahead. Speaking as someone who's flow many (at least 30) ~12 hour flights I know this is how it goes every 1/2 or hour you can feel them doing a slight turn (& can see it on the onboard radar)

why its crazy is, all air companys make bugger all profits (if any) thus this wastage is pretty unbelievable

 

[aaronspink]

they never did, what they did was fly from waypoint to waypoint, flightpath corridoor (see the map above over the UK) now the shortest path between 2 points on a globe is a curve right? but u will see there after it takes off, it flys ~1000km straight ahead then does a ~5 degree turn to the left (just above the hebridis) and then flys straight ahead. Speaking as someone who's flow many (at least 30) ~12 hour flights I know this is how it goes every 1/2 or hour you can feel them doing a slight turn (& can see it on the onboard radar)

why its crazy is, all air companys make bugger all profits (if any) thus this wastage is pretty unbelievable

For pretty much any location except deep southern pacific routes, located beacon flying is within noise margin of great circle or best route (aka modulo winds). It is only the deep south pacific routes that have a lack of beacons.

 

[KimB]

they never did, what they did was fly from waypoint to waypoint, flightpath corridoor (see the map above over the UK) now the shortest path between 2 points on a globe is a curve right? but u will see there after it takes off, it flys ~1000km straight ahead then does a ~5 degree turn to the left (just above the hebridis) and then flys straight ahead. Speaking as someone who's flow many (at least 30) ~12 hour flights I know this is how it goes every 1/2 or hour you can feel them doing a slight turn (& can see it on the onboard radar)

why its crazy is, all air companys make bugger all profits (if any) thus this wastage is pretty unbelievable

Following a great circle involves only flying straight ahead. There are no turns involved with an aircraft that follows a great circle path. The waypoints are generally used to make sure they stay on course, and the turns are likely course corrections to either avoid storms, to get back on path after drifting off the flight plan, or because the aircraft hasn't followed a great circle path for some reason or other.