[AnneFrothingslosh]

There are north-centered, bipolar, etc. map models. But what is the real map? What are the pros and cons of each?

[Tom Bishop]

Rowbotham's original society solved the sinking ship. Lady Blount's society collected the professional surveyor and railway proofs. This specific society's contribution to Flat Earth has been the celestial model and the gravitational model. Progress was made on these subjects because they are things we can see and test. And with that, we have basically been done here with our current constraints. If you ask me what is happening on earth thousands of miles away, there will be less research there. The total world model is a topic for the next generation of FE to figure out.

At the current trajectory I estimate that it will take twenty or thirty more years for the wider Flat Earth community to actually figure out and perform and repeat the necessary tests that check all the boxes.

At the moment among the Monopole supporters there seems to be some division on whether there are faster winds in the south or whether the planes are actually following the straight line Flat Earth Azimuthal path to their destination, as evidenced by emergency landings.

Someday they might figure it out, but it's not going to be anytime soon.

[DuncanDoenitz]

"... faster winds in the south ....".  Ah yes, we've been here before. 

Amongst others at the moment, (now, 0912UTC on 2 May 2024) LAN-Chile has 2 Boeing 787 Dreamliners airborne over the South Pacific. 

Reg CC-BGG is operating as LAN801 from Santiago to Auckland, a route planned as about 5300NM.  The aircraft is just under halfway and estimates completing the journey with a flight time of 12 hours, giving an average ground speed of 440 kts. 

Its sister ship, CC-BGH is operating as LAN804 from Melbourne to Santiago, a route planned as about 6200NM.  The aircraft is about halfway and estimates completing the journey with a flight time also of 12 hours, giving an average ground speed of 520 kts. 

Taking the average of the westbound and eastbound flights, 480 kts, would suggest an westerly wind component of 40 kts acting as a headwind hampering LAN801 and assisting LAN804.  Wikipedia lists the cruising speed of a Dreamliner as 488 to 516 kts. 

As the captains of both aircraft would not have departed unless they were sure of the distance and fuel needed, I would suggest that calculating the distance from South America to Australasia has been calculated in considerably less than "20 to 30 years", and that the windspeeds are well understood. 

[Tom Bishop]

"... faster winds in the south ....".  Ah yes, we've been here before. 

There was a link there: https://wiki.tfes.org/Issues_in_Flight_Analysis

I am asking you guys to address the topics in the link, rather than just read and ignore it and pretend that nothing was posted.

Amongst others at the moment, (now, 0912UTC on 2 May 2024) LAN-Chile has 2 Boeing 787 Dreamliners airborne over the South Pacific. 

Reg CC-BGG is operating as LAN801 from Santiago to Auckland, a route planned as about 5300NM.  The aircraft is just under halfway and estimates completing the journey with a flight time of 12 hours, giving an average ground speed of 440 kts. 

Its sister ship, CC-BGH is operating as LAN804 from Melbourne to Santiago, a route planned as about 6200NM.  The aircraft is about halfway and estimates completing the journey with a flight time also of 12 hours, giving an average ground speed of 520 kts. 

Taking the average of the westbound and eastbound flights, 480 kts, would suggest an westerly wind component of 40 kts acting as a headwind hampering LAN801 and assisting LAN804.  Wikipedia lists the cruising speed of a Dreamliner as 488 to 516 kts. 

As the captains of both aircraft would not have departed unless they were sure of the distance and fuel needed, I would suggest that calculating the distance from South America to Australasia has been calculated in considerably less than "20 to 30 years", and that the windspeeds are well understood. 

Those numbers are around the plane's cruise speed. But the plane should not be traveling at a speed around its cruising speed, since we know that on long haul flights planes across the oceans planes use jet streams to reach their location. It would be traveling the plane's cruising speed + jet stream.

Jetstreams even enable supersonic flight for commercial aircraft.

On the flight trackers there have been some interesting anomalies. Jeran shows at the 1h32m mark of the following video about the flight between Auckland and Santiago that True Airspeed can be seen to far exceed ground speed. Over the course of the flight the True Airspeed is either "N/A" or shows quite fast speeds.

https://www.youtube.com/watch?v=GKKHY72x3ZU

Screen shot:

[Action80]

The answer to this question is entirely dependent on the purpose for which it was asked.

No one navigates utilizing a map of the entire earth.

Waypoints utilized for navigation by seafarers and aviators have been transcribed to the flat earth plane utilizing overhead coordinates of matching guiding light points from the celestial sphere above our heads.

[AATW]

Rowbotham's original society solved the sinking ship.

Did it, though? He spends some time in ENaG claiming that things like ladies dresses disappear bottom first on a flat path, which they don't. And then he claims that ships which have gone over the horizon can be "restored", which they can't.

Lady Blount's society collected the professional surveyor and railway proofs.

Did they? Well where are those then? I looked her up and found something about some photo they took. It's here:
https://en.wikipedia.org/wiki/Elizabeth,_Lady_Blount#/media/File:Blount-photo-bedford-level.jpg
What the hell is that supposed to be?!

EA and UA are admittedly pretty good explanations for certain observations BUT they are just that.
The sun can't set on a FE where the sun is above the plane of the earth at all times. So EA is used as an explanation. It's not a bad one, but it's at best a hypothesis that "light bends upwards", and the formula shown in the Wiki has no derivation and an unknown constant.
The model mainstream physics has of gravity can't work on a FE so UA is used as an explanation. Again, not a bad one but it doesn't explain variations of gravity so those have to be hand-waved away.

This is an issue with your way of enquiring. You form a theory which explains observation rather than forming a hypothesis and then making observations which test that hypothesis - which then becomes a theory as observations build confidence. I know this is deliberate, and working the other way around could lead to the same conclusions. The issue though is when observations are presented which show your theory to be wrong you just claim they're wrong/flawed/fake. That's not a way to make progress.

If you ask me what is happening on earth thousands of miles away, there will be less research there. The total world model is a topic for the next generation of FE to figure out.

Is it, though? There are flat earthers all around the...disc, right? And we have instant communications now.
There are surely ways you can do large scale experiments reasonably cheaply. I'm sure you could club together and get a ticket for a Santiago to Sydney plane ticket, a FE person on that flight could gather a load of data which would help you advance things.

Are you now leaning towards the bi-polar model? That does solve some issues - like how there are jobs in Antarctica, sailing races around it and so on. But I'm not sure how the 24 hour sun works in the Arctic and Antarctic AND the other observed patterns of light and motion of the sun would work. It solves some problems which the monopole model has in the southern hemisphere, but it seems to create some equally big ones.

[Action80]

The sun can't set on a FE where the sun is above the plane of the earth at all times.

Do you have evidence to back up this outright lie?

Why do you persist in repeatedly writing this outright lie on this forum?

[AATW]

The sun can't set on a FE where the sun is above the plane of the earth at all times.

Do you have evidence to back up this outright lie?

Yes. The evidence is that if the sun is a few thousand miles above a flat earth then you would have a clear line of sight to it at all time. What would stop you seeing it? It would also change significantly in angular size, angular speed and luminosity throughout the day as your distance to it varies. None of that happens.
All that is in the context of the mainstream physics. You may have other mechanisms to explain this - EA, some magnification effect and I'm not sure about the luminosity one - the sun does admittedly change at sunset, but not during most of the day as it surely would if the sun was at a significantly different distance.

As I said, EA is a reasonable explanation. It's better than "perspective" which makes no sense at all. But it is at best a hypothesis, not a well formed theory.

[Action80]

The sun can't set on a FE where the sun is above the plane of the earth at all times.

Do you have evidence to back up this outright lie?

Yes. The evidence is that if the sun is a few thousand miles above a flat earth then you would have a clear line of sight to it at all time.

A statement made by some random contributor to this forum does not constitute evidence.

You should be able to model it on scale to back up your claim.

What would stop you seeing it?

Lots of things...distance for one, physical aspects of the aether for two, occluding objects for three...I could go on.

It would also change significantly in angular size, angular speed and luminosity throughout the day as your distance to it varies. None of that happens.

Just another baseless statement based on your inability to envision alternate and, certainly possible, modes of operation.

All that is in the context of the mainstream physics. You may have other mechanisms to explain this - EA, some magnification effect and I'm not sure about the luminosity one - the sun does admittedly change at sunset, but not during most of the day as it surely would if the sun was at a significantly different distance.

As I said, EA is a reasonable explanation. It's better than "perspective" which makes no sense at all. But it is at best a hypothesis, not a well formed theory.

"Mainstream physics"...joyfully uttered by most typical RE-zealots who visit this forum, as if they have any sort of grasp as to meaning.

You, of all contributors here, have the least amount of standing (based on the evidence of your posting history), to even include such a term in any of your posts.

[DuncanDoenitz]

Those numbers are around the plane's cruise speed. But the plane should not be traveling at a speed around its cruising speed, since we know that on long haul flights planes across the oceans planes use jet streams to reach their location. It would be traveling the plane's cruising speed + jet stream.

Jetstreams even enable supersonic flight for commercial aircraft.

On the flight trackers there have been some interesting anomalies. Jeran shows at the 1h32m mark of the following video about the flight between Auckland and Santiago that True Airspeed can be seen to far exceed ground speed. Over the course of the flight the True Airspeed is either "N/A" or shows quite fast speeds.

https://www.youtube.com/watch?v=GKKHY72x3ZU

A jetstream is just a wind, and I accounted for it in my calculation.  A look at any jetstream map will show that they are predominently westerly in the southern hemisphere, which corresponds with my previous statement and, if it is assisting the eastbound flight will it not be hindering the westbound which is occuring simultaneously and at similar latitudes? 

We've also done Jeran's thing before.  Simultaneous to the "supersonic" speeds is a series of altitude changes which an F-16 would struggle with.  Its just a batch of missing data on aircraft position; when it recovers the position data it integrates the delta-position over time to determine speed.   

[Action80]

Those numbers are around the plane's cruise speed. But the plane should not be traveling at a speed around its cruising speed, since we know that on long haul flights planes across the oceans planes use jet streams to reach their location. It would be traveling the plane's cruising speed + jet stream.

Jetstreams even enable supersonic flight for commercial aircraft.

On the flight trackers there have been some interesting anomalies. Jeran shows at the 1h32m mark of the following video about the flight between Auckland and Santiago that True Airspeed can be seen to far exceed ground speed. Over the course of the flight the True Airspeed is either "N/A" or shows quite fast speeds.

https://www.youtube.com/watch?v=GKKHY72x3ZU

A jetstream is just a wind, and I accounted for it in my calculation.  A look at any jetstream map will show that they are predominently westerly in the southern hemisphere, which corresponds with my previous statement and, if it is assisting the eastbound flight will it not be hindering the westbound which is occuring simultaneously and at similar latitudes? 

We've also done Jeran's thing before.  Simultaneous to the "supersonic" speeds is a series of altitude changes which an F-16 would struggle with.  Its just a batch of missing data on aircraft position; when it recovers the position data it integrates the delta-position over time to determine speed.

How did you account for it? Can you show the calculation?

[DuncanDoenitz]

I showed you the calculation at Reply#2.  Average the groundspeeds of 2 aircraft flying in opposite directions at a similar airspeed in a similar airspace; for each aircraft the difference from the average is the headwind/tailwind speed component. 

[AATW]

You should be able to model it on scale to back up your claim.

I could draw you a diagram I guess, but you can surely imagine this yourself. If an object is above a flat plane the all points on that plane are looking up at that object at an angle so have line of sight to it. Walk around a room illuminated by a lightbulb on the ceiling. Where in the room can you not see the lightbulb? Obviously in real life there will be things occluding the sun at times, which I'll come on to.

Lots of things...distance for one, physical aspects of the aether for two, occluding objects for three

Taking those one by one
Distance - when you can't see things because they're too far away they don't just go from "you can see them" to "you can't". They get smaller and smaller until you can't see them any more. Or if the issue isn't angular size but visibility then they gradually fade out, like someone walking away from you on a foggy day. That isn't what we observe at sunset. The disc of the sun is dimmer because of the angle, but it doesn't just slowly fade out. It disappears behind the horizon. In all other experiences of something disappearing like that it's because it's going behind something. So no, us not being able to see the sun because of distance does not match what we observe.

Physical aspects of the aether - you're going to have to explain what that means. What aspects of the aether?

Occluding objects - Obviously the sun is occluded all the time, at the moment I can't see it because it's cloudy. And when the sun is low in the sky then you might not be able to see it because of nearby hills or buildings or whatever. But it doesn't go dark. The sunglight is still hitting the atmosphere and scattering and illuminating the ground. What is stopping that happening on a FE? I've explained why distance and visbility aren't the issues.

It would also change significantly in angular size, angular speed and luminosity throughout the day as your distance to it varies. None of that happens.

Just another baseless statement based on your inability to envision alternate and, certainly possible, modes of operation.

It's "baseless" to state that objects get smaller in angular size as the distance between you and the object increases?

[Action80]

You should be able to model it on scale to back up your claim.

I could draw you a diagram I guess, but you can surely imagine this yourself. If an object is above a flat plane the all points on that plane are looking up at that object at an angle so have line of sight to it. Walk around a room illuminated by a lightbulb on the ceiling. Where in the room can you not see the lightbulb? Obviously in real life there will be things occluding the sun at times, which I'll come on to.

With the sun circling above, along with the celestial sphere, why would you not expect it to disappear from the view of persons in varying locations.

Lots of things...distance for one, physical aspects of the aether for two, occluding objects for three

Taking those one by one
Distance - when you can't see things because they're too far away they don't just go from "you can see them" to "you can't". They get smaller and smaller until you can't see them any more. Or if the issue isn't angular size but visibility then they gradually fade out, like someone walking away from you on a foggy day. That isn't what we observe at sunset. The disc of the sun is dimmer because of the angle, but it doesn't just slowly fade out. It disappears behind the horizon. In all other experiences of something disappearing like that it's because it's going behind something. So no, us not being able to see the sun because of distance does not match what we observe.

I addressed this fallacious response above.

Physical aspects of the aether - you're going to have to explain what that means. What aspects of the aether?

Aspects that would cause the light of the sun to be visible in some locations and not to be visible in others.

Occluding objects - Obviously the sun is occluded all the time, at the moment I can't see it because it's cloudy. And when the sun is low in the sky then you might not be able to see it because of nearby hills or buildings or whatever. But it doesn't go dark. The sunglight is still hitting the atmosphere and scattering and illuminating the ground. What is stopping that happening on a FE? I've explained why distance and visbility aren't the issues.

Addressed above.

It's "baseless" to state that objects get smaller in angular size as the distance between you and the object increases?

Will you make up your own mind here for the benefit of the readership, please?

Why on earth would you claim the luminosity of the sun does not change throughout the day? Of course, it does.

Why on earth does the angular size of the sun actually appear larger to the naked eye at dawn and dusk? Of course, it does.

Just some of the possible effects of the aether.

[AATW]

With the sun circling above, along with the celestial sphere, why would you not expect it to disappear from the view of persons in varying locations.

Because the sun remains above the plane of the earth at all times.
In ancient flat earth models the sun went up and over the earth in the day and underneath at night. Day was day everywhere, night was night everywhere. They didn't know that when it's day in the UK it's night in Australia. With a sun which is always above a flat earth it should illuminate the whole of the disc. Unless there's some reason it can only be seen for a certain distance, which is plausible, but then you'd get the sun slowly fade in and out as the distance to it decreased or increased. That isn't what we observe.

Aspects that would cause the light of the sun to be visible in some locations and not to be visible in others.

That's just a bunch of words. Give some details. You can't just reject the notion that the sun sets because we live on a rotating globe and then replace that with something vague about "aspects of the aether" with no details about what you mean by that.

Why on earth would you claim the luminosity of the sun does not change throughout the day? Of course, it does

During sunrise and sunset the light scatters through more of the atmosphere so yes, that does affect the luminosity, but not in a way consistent with your theory of a sun rotating above us. That would mean the distance to the sun constantly changing and that would surely affect the luminosity. Again, if visibility is the reason we can't see the sun at night then it would fade out, not set.

Why on earth does the angular size of the sun actually appear larger to the naked eye at dawn and dusk? Of course, it does.

I've bolded the word appear. Yes, there is a known optical illusion which makes this happen, in reality it's not actually bigger. And if that were true then that's the exact opposite of what you'd expect on a FE where the sun is at a significantly greater distance from you at sunset than at midday. That would make it appear smaller at sunrise and sunset. Again, I don't feel I need to provide any evidence for the assertion that things get smaller as they get further away from you.

[Action80]

With the sun circling above, along with the celestial sphere, why would you not expect it to disappear from the view of persons in varying locations.

Because the sun remains above the plane of the earth at all times.
In ancient flat earth models the sun went up and over the earth in the day and underneath at night. Day was day everywhere, night was night everywhere. They didn't know that when it's day in the UK it's night in Australia. With a sun which is always above a flat earth it should illuminate the whole of the disc. Unless there's some reason it can only be seen for a certain distance, which is plausible, but then you'd get the sun slowly fade in and out as the distance to it decreased or increased. That isn't what we observe.

That is exactly what is observed. Show an "ancient flat earth model" where it was day everywhere and night everywhere.
 

Aspects that would cause the light of the sun to be visible in some locations and not to be visible in others.

That's just a bunch of words. Give some details. You can't just reject the notion that the sun sets because we live on a rotating globe and then replace that with something vague about "aspects of the aether" with no details about what you mean by that.

One possibility is a condition similar to that of a veil.

Why on earth would you claim the luminosity of the sun does not change throughout the day? Of course, it does

During sunrise and sunset the light scatters through more of the atmosphere so yes, that does affect the luminosity, but not in a way consistent with your theory of a sun rotating above us. That would mean the distance to the sun constantly changing and that would surely affect the luminosity. Again, if visibility is the reason we can't see the sun at night then it would fade out, not set.

Addressed above.

I've bolded the word appear. Yes, there is a known optical illusion which makes this happen, in reality it's not actually bigger. And if that were true then that's the exact opposite of what you'd expect on a FE where the sun is at a significantly greater distance from you at sunset than at midday. That would make it appear smaller at sunrise and sunset. Again, I don't feel I need to provide any evidence for the assertion that things get smaller as they get further away from you.

Reflective properties (similar to a funhouse mirror) of a dome could account for what we see.

[Tom Bishop]

Rowbotham's original society solved the sinking ship.

Did it, though? He spends some time in ENaG claiming that things like ladies dresses disappear bottom first on a flat path, which they don't. And then he claims that ships which have gone over the horizon can be "restored", which they can't.

All of this is true of this effect though, and you have even admitted that the effect exists before in past conversations. See this past admission from 2022 from you:

But in any case, your "experiment" simply demonstrates the part I already wrote in bold above. The very thin hull in your picture will become hard to resolve at a certain distance. And yes, in that case optical magnification could "restore" it. But the reason it can be "restored" is that it isn't hidden in the first place. It isn't behind anything, it just becomes difficult to discern at a certain distance.

Which is exactly what Rowbotham is describing in Earth Not a Globe. When bodies are smaller than 1/60th of a degree they become lost to optical resolution, and are beyond perception. So, you were wrong. This effect does exist and it is reversible with optical zoom.

The experiment we discussed in that thread is still available for you to perform here:

https://wiki.tfes.org/Sinking_Ship_Effect_Caused_by_Limits_to_Optical_Resolution

Lady Blount's society collected the professional surveyor and railway proofs.

Did they? Well where are those then? I looked her up and found something about some photo they took. It's here:
https://en.wikipedia.org/wiki/Elizabeth,_Lady_Blount#/media/File:Blount-photo-bedford-level.jpg
What the hell is that supposed to be?!

The railroad references are here: https://wiki.tfes.org/Railroads

Yes, Lady Bount also verified Rowbotham's water convexity experiments with the then-new technology of long distance photography.

https://wiki.tfes.org/Bedford_Level_Experiment

The Old Bedford Level was the scene of further experiments over the years, until in 1904, photography was used to prove that the earth is flat. Lady Blount, a staunch believer in the zetetic faith hired a photographer, Mr Clifton of Dallmeyer's who arrived at the Bedford Level with the firm's latest Photo-Telescopic camera. The apparatus was set up at one end of the clear six-mile length, while at the other end Lady Blount and some scientific gentlemen hung a large, white calico sheet over the Bedford bridge so that the bottom of it was near the water. Mr Clifton, lying down near Welney bridge with his camera lens two feet above the water level, observed by telescope the hanging of the sheet, and found that he could see the whole of it down to the bottom. This surprised him, for he was an orthodox globularist and round-earth theory said that over a distance of six miles the bottom of the sheet should be more than 20 feet below his line of sight. His photograph showed not only the entire sheet but its reflection in the water below. That was certified in his report to Lady Blount, which concluded: "I should not like to abandon the globular theory off-hand, but, as far as this particular test is concerned, I am prepared to maintain that (unless rays of light will travel in a curved path) these six miles of water present a level surface."
—The Zetetic Website

Near the surface of the water, for at least the span of six miles, the light created a path which contradicted Round Earth Theory.

EA and UA are admittedly pretty good explanations for certain observations BUT they are just that.

A hypothesis typically does not have supporting evidence. However, the pages show that there is supporting evidence for celestial-scale, and possibly celestial-specific, bending of light.

https://wiki.tfes.org/Electromagnetic_Acceleration

This is an issue with your way of enquiring. You form a theory which explains observation rather than forming a hypothesis and then making observations which test that hypothesis - which then becomes a theory as observations build confidence. I know this is deliberate, and working the other way around could lead to the same conclusions. The issue though is when observations are presented which show your theory to be wrong you just claim they're wrong/flawed/fake. That's not a way to make progress.

Incorrect. There are observations to test the EA hypothesis of large celestial-scale bending.

If you ask me what is happening on earth thousands of miles away, there will be less research there. The total world model is a topic for the next generation of FE to figure out.

Is it, though? There are flat earthers all around the...disc, right? And we have instant communications now.
There are surely ways you can do large scale experiments reasonably cheaply. I'm sure you could club together and get a ticket for a Santiago to Sydney plane ticket, a FE person on that flight could gather a load of data which would help you advance things.

People sitting in a plane have a difficult time telling how much the winds and the jet stream are adding to the journey. Planes have a hard time determining their true speeds because they are propelling themselves in pockets of fluids which itself is traveling through larger scales of fluids. Wind-intake odometers for planes are notoriously inaccurate. Comparing yourself to Lat/Lon coordinates would also change your speed depending if you are assuming an RE or and FE which has different spacing between the coordinate points. There needs to be an independent method of speed determination.

[Tom Bishop]

A jetstream is just a wind, and I accounted for it in my calculation.  A look at any jetstream map will show that they are predominently westerly in the southern hemisphere, which corresponds with my previous statement and, if it is assisting the eastbound flight will it not be hindering the westbound which is occuring simultaneously and at similar latitudes? 

We've also done Jeran's thing before.  Simultaneous to the "supersonic" speeds is a series of altitude changes which an F-16 would struggle with.  Its just a batch of missing data on aircraft position; when it recovers the position data it integrates the delta-position over time to determine speed.

The speeds you provided for the Southern Hemisphere flights were too low. You stated "40 kts acting as a headwind hampering LAN801 and assisting LAN804". Jet streams are far faster, and we know that long haul flights take advantage of the Jet Stream.

https://skybrary.aero/articles/jet-stream

"To be considered a Jet Stream, the accepted minimum speed limit is 60 knots. The speed of the Jet Stream is typically 100 kts (nautical miles per hour) but can reach 200 kts over North America and Europe in the winter. Speeds of 300 kts are not unheard of, particularly over south-east Asia."

Commercial flights would fly at the the plane's cruising speed + the Jet Stream speed. See this article from a Northern Hemisphere event over the Atlantic Ocean:

https://www.cnn.com/travel/article/jet-stream-flights-speed-of-sound/index.html

'In February 2019, a Virgin Atlantic plane flew at 801mph from Los Angeles to London, reaching its top speed over Pennsylvania thanks to a 200mph jet stream – although it slowed down to a mere 710mph once it hit the ocean. The aircraft – a Boeing 787 Dreamliner – usually has a cruising speed of around 560mph. Virgin founder Richard Branson described it as flying “faster than any other commercial non-supersonic plane in history.”'

[DuncanDoenitz]

You're talking about the jetstreams as being a constant phenomenon.  They aren't, they are variable, in location, direction and velocity.  Like I said, its just a wind.  If its above 60 kts, as you say, they term it a jetstream, but its still just a wind. 

And you are absolutely correct that favourable jetstreams (like other winds) are exploited for the purpose of speed and economy, but if the jetstream is absent, or unfavourable, the flights still occur.  Just look at the post-Covid-resurrected Qantas/LAN services between Chile and Australasia; they take place on schedule every time, eastbound and westbound.  They can't be that anomalous can they? 

Now try Googling Air France flight AF174 on 8 May.  (Or here's a link);

https://www.flightradar24.com/data/flights/af174?utm_campaign=website&utm_medium=email&utm_source=sendgrid.com#351eba3d

Airbus A350 F-HUVC departed Paris CDG as AF174 for Mexico City but developed a problem over Newfoundland and returned to CDG.  Flight tracking data shows that the return leg was performed almost completely along the same route and at a similar altitude as the outbound leg.  Pretty dumb with a 300mph wind wasn't it, or maybe the airline actually knew the windspeed? 

[Tom Bishop]

You're talking about the jetstreams as being a constant phenomenon.

Correct. The jetstreams are present year-round.

https://www.popularmechanics.com/science/environment/a9181/how-the-dual-jet-stream-sparks-this-weird-summer-weather-15634917/

"The jet stream is a year-round feature of our atmosphere, but the double jet stream phenomenon is more common in winter."

https://www.rmets.org/metmatters/jet-stream-weakening

"In the UK, we feel the influence of the polar jet stream (which is also sometimes called the ‘mid-latitude’ or the ‘eddy-driven’ jet stream), which forms due to the difference in the temperatures between the pole and equator. On its northern side lies colder air, and on its southern side warmer air – so its position is important for what type of weather we experience in the UK. It waxes and wanes with the seasons, being strongest in winter, but is a year-round phenomenon."

https://en.wikipedia.org/wiki/Jet_stream

"The northern hemisphere polar jet flows over the middle to northern latitudes of North America, Europe, and Asia and their intervening oceans, while the southern hemisphere polar jet mostly circles Antarctica, both all year round."

They aren't, they are variable, in location, direction and velocity.  Like I said, its just a wind.  If its above 60 kts, as you say, they term it a jetstream, but its still just a wind. 

And you are absolutely correct that favourable jetstreams (like other winds) are exploited for the purpose of speed and economy, but if the jetstream is absent, or unfavourable, the flights still occur.

They don't. Flights are canceled all the time, especially long haul flights. See this quote by travel writer Maggie Teneva:

“Long-haul flights are often associated with long layovers and delays or cancellations.”

If there are unexpected changes to the jet stream or winds mid-flight, a non-stop flight might even stop for fuel:

“ Dozens of Continental Airlines flights to the East Coast from Europe have been forced to make unexpected stops in Canada and elsewhere to take on fuel after running into unusually strong headwinds over the Atlantic Ocean.

The stops, which have caused delays and inconvenience for thousands of passengers in recent weeks, are partly the result of a decision by United Continental Holdings Inc., the world's largest airline, to use smaller jets on a growing number of long, trans-Atlantic routes. ”

Per ETOPS, plane flight routes are required to be in vicinity of airports or landing strips for unexpected stops like that. Even long haul flights over oceans need the capability to make detour routes to islands with landing strips in case something like the above happens. The US Military is even known to maintain landing strips on certain uninhabited islands in remote locations for ETOPS purposes.

Just look at the post-Covid-resurrected Qantas/LAN services between Chile and Australasia; they take place on schedule every time, eastbound and westbound.  They can't be that anomalous can they? 

Now try Googling Air France flight AF174 on 8 May.  (Or here's a link);

https://www.flightradar24.com/data/flights/af174?utm_campaign=website&utm_medium=email&utm_source=sendgrid.com#351eba3d

Airbus A350 F-HUVC departed Paris CDG as AF174 for Mexico City but developed a problem over Newfoundland and returned to CDG.  Flight tracking data shows that the return leg was performed almost completely along the same route and at a similar altitude as the outbound leg.  Pretty dumb with a 300mph wind wasn't it, or maybe the airline actually knew the windspeed?

The Jet Stream can change in nature within hours. This is why those non-stop flights stopped for fuel in the previous quote I gave. Those planes didn't take off knowing that the winds would be unfavorable. Planes have a network which tracks the Jet Stream to follow the best path in real time. If that was the path it took, then it is simply because the flight logistics people determined that it was the best path at that specific time.

https://en.wikipedia.org/wiki/Jet_stream

"Jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various directions including opposite to the direction of the remainder of the jet."

In this case, the jet stream probably just moved out of the way and the plane had enough fuel in its wings to take a long trip back, or there was a favorable path at a lower altitude.

Most typically, the planes take different routes on the return trip:

https://aviation.stackexchange.com/questions/29729/why-are-westbound-transatlantic-routes-located-hundreds-of-km-away-from-eastboun

Why are westbound transatlantic routes located hundreds of km away from eastbound routes?

Looking at flights between NY and London (click to see route):

BA 185 (EGLL - KEWR)
United 941 (EGLL - KEWR)
United 16 (KEWR - EGLL)

The FlightAware anticipated routes are quite similar in both directions, but the actual routes for past flights are really remote from each other:



The two westbound routes are either 800 km north or 1,000 km south of the eastbound route (the dotted line shows the shortest path).

Why are the two westbound routes different and so remote from each other? Why this difference of about 1,800 km?

Why BA 185 route seems to be composed of two arcs?

Did the pilots changed their mind in flight because of the jet streams? Is it related to ETOPS constraints, or alternate airport at Santa Maria? or something else?