SYD - JNB latitude

[aussiepax]

Hi team,

Can any pilots or experts tell me if the SYD- JNB route is still a great circle route as it was when the 744 did the route ?
Now it is a 787-9, do the ETOPS rules mean that it doesn't go to such southern latitudes ?
I am just noticing on Flight radar that the plot looks a bit further north than in those days.

Thanks for any answers.

[India Four Two]

From gcmap.com:

180 minute ETOPS:
https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/1522x1086/screenshot_2023_02_12_at_08_39_29_684a02642174dca1d393e1a1a9 8357cf61ef10b3.png

330 minute ETOPS:
https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1514x1078/screenshot_2023_02_12_at_08_38_33_3e593d15eb93df807b4ed8f605 2d75bd87e5cb20.png


The FAA has approved additional extended operations (ETOPS) for the Boeing 787. The move allows 787s to be operated up to 330 minutes from a landing field. ​​​​​​​​​​​​​​
https://airinsight.com/boeing-receives-330-minute-etops-certification-for-787/

[aussiepax]

Thanks, yet today's flight path is barely south of the Australian cont
https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/1489x788/capture_qf63_9043039bd23a763e80f0092ff11648606da62739.png
inent !

[aussiepax]

Maybe there was a MEL problem ? check out today's track
https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1472x815/capture_qf63_bb05c5dea3a5d85893ddf524c6d0be0bb096b6ea.png

[WingNut60]

The answer might be found by looking at wind altitude.

[wiggy]

The answer might be found by looking at wind altitude.

Could well be - delurking from this section to drop in, for illustrative purposes, a link:

https://www.windy.com/?200h,-32.479,71.016,3,m:cXLah5t

As a general point for the OP it's worth bearing in mind that Great circle doesn't always give you minimum cost/minimum time on a route.

[aussiepax]

Great, thanks for that interesting info ! I didn't realise such major variations in route, wrt wind.

[India Four Two]

I've travelled many times across the North Atlantic from Europe to Western Canada, and also across the Pacific from North America to Asia. The westbound flights often deviate from the Great Circle route to avoid strong headwinds. Here are some typical Great Circle tracks across the North Pacific:

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/1500x768/screenshot_2023_02_13_at_11_12_02_3792bcf0c891570f852069a5da 06997bcd7ee17f.png

Westbound flights will often deviate north of the optimum tracks to avoid the headwinds associated with low-pressure systems in the Gulf of Alaska.

One extreme example was the longest flight I have ever done - Los Angeles to Bangkok non-stop - nearly 18 hours. There were two low-pressure systems in the Bering Sea with 200 kt headwinds. As a consequence, we flew way further north than usual and managed to cross the Pacific without flying over it!

The distance penalty was not as much as it looks. The Great Circle track is 7186 nm and our track that day was about 400 nm further, plus the mandatory messing around in China due to military ATC. We flew an almost semi-circular arc around Beijing before proceeding on course!

https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/1192x1178/screenshot_2023_02_13_at_11_02_42_bc4ae93d40d16b981309552115 44675b8988aa8a.png

[aussiepax]

Cool , and fascinating. Thanks everyone !

[pax britanica]

There can be some very extreme variations , just recently I saw a SQ (Singapoe Airlines ) fight on FR 24 crossign Southern England en route to Singapore from New York

THe great circle takes it over western siberia, the pole m eastern canada and down to JFK and it often sues that route but with very strong westerlies the much longer distance was beign covered in less hours so thats the way it went that day.

Youcan also see soem India-US flights which leve india heading due north but when they get up to the artci circle in the north of Russia one day they turn left the next they turn right.

These extreme range trips cana nd do deviate a lot from the simple GC becuase they cover so much ground they often take advanatge favourable weather since if you are aloft for 17 plus hours you are covering large part of the earths surface

[dixi188]

I remember hearing the Singapore Airlines SIN-JFK on a london frequency soon after the route started. The controller asked the flight time, the answer was "13 down 6 to go". The Great Circle route would have been about 30 degrees further north, almost over the pole.
We were doing CGN-DUB.

[Mr Mac]

Dixi188
Did that route on A340 and the route changes due to winds. I did westerly over Europe and indeed Easterly over Japan and Canada, but it is a bloody long flight. All business class back then.

Cheers
Mr Mac

[India Four Two]

they often take advanatge favourable weather

What was known in the piston-airliner days as "Pressure Pattern Flying". Perhaps it still is?

[Asturias56]

sometimes - but sometimes they just have to batter into the head wind - I can remember a particularly gothic trip SIN-LHR - it would have been faster to land in Romania and drive the damn plane along the freeway to Calais

[Trinity 09L]

I have also noticed that Japan to Europe flights now head north east? through the gap between Russia and USA and over the North Pole to Europe. Obviously no overflying Russia, so a longer route and within ETOPS but a fuel and time penalty. Not applicable to ME and 2 Asian carriers.

[pax britanica]

I lived in Bermuda all opf the 80s and did a trip back to London ona monday ona L1011 (lovely) we did the trip in 5 hours 2 mins with a massive sprng tail wind -direct great circle BDA to Lands end .
Going back athree days later -same kind of weather we route over iceland down to Nova Scotia and due south to BDA . Flight time nearly 9 hours . luckily it was -500 as not sure the full sized ones would have made it without a stop. On the way abck the captain made a PA ( a lot of very regular biz travelers on that route ) that we were leaving the UK over Machrihanish (?) in western Scotland when the nornal depatrues were duirect to Lands end and very occasionally Brecon in Wales .

In some way todays airlliners are at the mercy of the winds as much a sailing ships were