Why don't planes fly west

16,575 km | Why do planes so rarely fly over the Pacific?

Many flights cross the Atlantic, but what about the Pacific? In many cases, isn't it a shorter time to fly across the Pacific? Anyone who has ever looked at a flight radar knows that there is not much going on over the Pacific. But why is that?

It is simply wrong that there are no flights over the Pacific at all. A route that is flown a lot is, for example, the one between Hawaii and the USA.

But flights that cover the entire Pacific are rare. This is particularly evident when you compare the Pacific airlines with the Atlantic [With smartphone and co .: use the "+" button until the airlines (light blue) are displayed]:

Here you can clearly see that there is more going on across the Atlantic. And flights that cross the Pacific usually make a stopover in Hawaii. (move the map with the mouse if you want to see the rest of the world)

But long-haul flights that cross the entire Pacific have been around for a long time. There are various reasons why there are so few. Probably the most important is: The Pacific is damn big. 35% of the entire surface of the earth - and thus more than all continents combined. No wonder that the world's longest passenger flight is across the Pacific.

How big the Pacific really is is easily overlooked on the usual 2D maps. But if you look at the world as a globe, you can almost only see water.

Flights that cover the entire Pacific

In the top 10 longest passenger flights in the world, around half are across the Pacific. This also includes the longest passenger flight - with a length of around 16,600 km.

In order to illustrate in the following how flight routes over the Pacific are chosen, I have chosen two quite different flights from the top 10:

  • SQ22 from Singapore to New York
  • UA101 from Houston to Sydney

SQ22 is the longest passenger flight in the world today. As with all flights, the actual route flown varies depending on the weather.

On May 14, 2019, the aircraft did exactly 16,575 km covered. These are 18 hours and 18 minutes Flight time.

Above you can see the map of the entire flight route. A good 60% of the route leads across the Pacific.

Now one could argue that SQ22 does not actually cross the Pacific “properly”. After all, this one literally scratches the land mass above.

So it almost looks like it's too dangerous to cross the Pacific in a straight line. Or why else does the airplane fly such a large arc?

I will explain below why airplanes fly such an “arc”.

First, let's look at the second flight. UA101 from Houston to Sydney.

In contrast to the SQ22, a good 90% of the route is across the Pacific Ocean.

Here the route looks a lot straighter. UA101 is with 14,204 km Length is the number 6 longest passenger flight in the world.

Flying over the Pacific does not seem too dangerous.

But why then are there so few flight routes across the ocean? There are several reasons for this. The 3 most important factors are:

  1. Choosing the shortest route
  2. Airways and waypoints
  3. wind and weather

1. The shortest route is rarely across the Pacific

The shortest connection between two airports is that Beeline. Or the so-called Great circle.

Overall, the straight line and the great circle describe the same thing: The shortest connection between two points on a sphere.

And that is exactly the most important factor that goes into determining the flight route. Of course, airlines want to fly the shortest possible route.

You can see what the shortest connections of our example flights look like in the following picture:

What is immediately noticeable is that the upper section (SQ22) no longer crosses the Pacific at all. The shortest route is now across the North Pole.

In contrast, the route of the lower flight (UA101) does not seem to have changed that much.

Why the actual flight routes differ from the shortest routes is due to the factors mentioned above, such as Wind and waypoints.

What is important here is the knowledge that Flights across the Pacific are rarely the shortest route. Connections across the Arctic Circle or other continents are often shorter.

Connections between North America and Australia (as well as Southeast Asia) via the Pacific may still make sense. The best way to get to the rest of Asia is via Europe or the Arctic Circle.

When the arch becomes “straight”

Above we looked at the actual flight route from New York to Singapore (SQ22) on a 2D map. That produced a clear arc.

Anyone who looks at flight trackers often knows that flights rarely fly from point to point in a straight line. Often you get a bow similar to the SQ22. That's because of the 2D representation of the map. Unfortunately, I haven't found a flight tracker that shows flights directly on one 3D globe represents.

And no - that is not evidence of a flat earth. (Unfortunately you come across such arguments surprisingly often when dealing with flight routes)

To illustrate how the whole thing looks on a 3D Earth, I imported the same flight into Google Earth.

Lo and behold, the supposed arch of the 2D map has disappeared. The actual flight (green) does not correspond to the shortest route (red), but the flight route no longer looks like an overly long detour.

2. Airways and waypoints

Airlines use various means to navigate their flights. This mainly includes airways and waypoints.

Airways and waypoints define the routes over which planes fly. While airways almost completely determine the flight routes over land, the airlines have more leeway over the oceans. There are also airways here, but direct connections between waypoints are also often used.

Airways are nothing more than roads in the air. These can be found above all over the country. This means that every flight starts and ends in clearly defined airways - even if the majority of the route here is over an ocean.

The task of airways is to regulate the traffic and thus avoid collisions. Airplanes therefore have to follow airways, even if they have to take a detour. Airways are managed by the respective air traffic control.

All Airways themselves are through so-called Waypoints connected. Whereby several waypoints can lie on one airway.

Waypoints are used for orientation in aviation. Aircraft use waypoints, e.g. to change airways. If no suitable airways specify a route, it is also possible to fly from waypoint to waypoint.

Most of the flightsacross the Pacific run as follows:

  1. Flight from the starting airport via airway to a waypoint # 1 near the coast of the starting continent
  2. Flight from waypoint # 1 over the ocean (via a defined airway, other waypoints or even directly) to a waypoint # 2 near the coast of the destination continent
  3. Flight from waypoint # 2 to the destination airport

This can be shown particularly well on our second flight, UA101 from Houston to Sydney. The route of the aircraft does not follow an air route here, but connects several waypoints.

However, with flying other waypoints, the shortest route would have been possible (red). Why the detour via the waypoint here CAMOS was flown is probably due to the third factor: wind and weather.

3. Wind and weather

Wind and weather play an important role in aviation. Here, dangers such as strong turbulence and icing are effectively avoided — or winds are used or avoided in order to get to your destination more efficiently.

If you fly with the right wind, you can be up to 400 km / h faster. On February 18, 2019, a Boeing 787 reached a whopping 1289 km / h instead of the usual 900 km / h due to the tailwind of a jet stream.

In order to be able to use the wind conditions for themselves, the airlines evaluate weather data around the clock. This results in flight routes that are updated every few hours and that represent an efficient air route.

Transferred on our flight UA101 This makes it easy to see why the detour via the waypoint CAMOS had an advantage over the direct route:

Here you can see that at the beginning of the route (right) the jet stream (purple / white) was flown around. Instead of Headwinds of up to 200 km / h was here in one light headwind (blue) flown (below 50 km / h).

Jet streams are the strongest naturally occurring winds. These are, among other things, at cruising altitude and always act in the same direction overall: from west to east.

If you have ever flown from Germany to New York, you may have noticed that the return flight is a good hour shorter. This is because the planes can use the jet stream between North America and Europe on their return flight.

Flight UA101 is flying in the opposite direction, so here you try to avoid the jet stream.

If you look at the same weather map 5 days later, you can see that the jet streams have shifted. And thus also the flight route used.

Overall, both flights were about the same length (only 33 km difference). But the second flight on May 20th, 2019 took a good 30 minutes less. When comparing the maps, it is noticeable that this flight was able to fly through the jet stream more effectively at the end of the route (left).

Conclusion

Airplanes don't just fly over the Pacific. Planes fly everywhere — provided the route is efficient.

If you look at different maps - great circle, waypoints, wind map - you can quickly see how the flight routes chosen by the airlines come about.

If you want to take a closer look at the tools used (or the rest of the world instead of the Pacific), they are all listed again here:

If you want to see more examples, check out my article on airlines passing in the arctic circles.

Have you ever flown across the Pacific? Or did the article even help you answer a question about other airlines?

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Categories Knowledge & Technology

John Hoffmann

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Aviation Student. Data collector. Travel optimizer.