There are a lot of variables in getting from A to B. Are you going on the highway? Do you want to pay a toll? What do you think about the traffic? Depending on how far you travel, your route can change.
You might think the fastest route would be the most direct line, as the crow flies. This is not always true. You may have noticed that a flight rarely takes the exact straight line route if you have watched the flight map while flying. It is possible to fly between the same cities on the same flight multiple times a day.
What is going on with this?
It is important to note that the shortest route and the fastest route are not the same.
When flying from London to San Francisco, you should take off from London, cross the Atlantic to Eastern Canada, and zoom over the central part of the U.S. to San Francisco.
The reality is not the same as you can see in the image below.
The flight goes off in the opposite direction and takes a scenic route over the northern part of Canada. What's the reason?
The answer is that the Earth isn't flat as depicted in the maps. If you take a piece of string and place it on a globe between the two cities, you will see that the shortest route is up over Greenland and is known as a Great Circle.
The route that the United flight took wasn't the same as the Great Circle route.
You can sign up for our newsletter.
It may not be the fastest route due to a number of factors.
There is unseen detail behind every flight.
The winds are a big variable in this equation. The earth is spinning and global winds move from west to east. When flying west, aircraft travel into head winds and when flying east, they travel into tail winds. What does this mean for planes?
As you turn a corner on a windy day, you suddenly find yourself fighting a stiff head wind. If you want to keep up the pace, you have to use more energy.
If you turn in the opposite direction, your pace will pick up. The same thing happens for aircraft.
We use more fuel when we fly west because our speed slows down when we fly against the wind. The wind increases our groundspeed when we fly east. The amount of fuel we use is reduced.
The eastern part of a city is usually quicker than the western part.
In the areas of jet streams, these winds are most noticeable. The green lines depict them.
The overall path of the jet streams does follow that rule even though they aren't exactly west to east. The jet streams will change in strength and location depending on the weather system.
Flight planning departments try to avoid the strongest of the jet streams when flying west. Flying a route that takes the aircraft off the Great Circle track will result in a quicker flight time than the route on the Great Circle line.
The atmosphere and winds have an effect on your flight.
The opposite is true when you fly east. Flight planners will try to get aircraft into the core of the jet streams in order to take advantage of the strong tail winds. The strong tail winds will increase the ground speed and reduce the flight time.
There is a great visualization of this in the clip below.
The amount of traffic is one of the variables shown in this clip.
Traffic jams in the sky may seem crazy. Too many aircraft trying to get through a certain area at the same time can cause traffic jams.
The beauty of international flight planning systems is that air traffic controllers can see where issues may occur. The routes between Europe and southern and east Asia are limited due to the situation in a number of countries around the world.
Air traffic control agencies will place departure time restrictions on some aircraft even before they leave the gate if there is a backup in the area. This is referred to as a slot.
Flight planners have two options if this happens, they can either wait for the slot restriction and take the originally planned route or they can look to change the route.
There are a number of variables that will determine the option they choose. The variables include the cost difference in fuel, the difference in time, and the cost of missing connections.
It might be a better idea to wait for the slot time to come around. Sometimes a detour is the best option if it is hours away.
The routes that aircraft can and can't fly have a lot to do with the geopolitics of the area. Most airlines are not allowed to fly through Russian airspace right now. The security situation on the ground in a number of African and Middle Eastern countries makes it impossible for planes to fly through their airspace.
The route a flight takes on a specific day is dependent on these factors. Flying 43,000 feet above a country may be safe, but flight planners and pilots always have to think about technical issues that could cause us to descend and divert the plane.
airlines constantly stay on top of the latest safety and security information around the world to make sure that their aircraft, passengers and crews never end up in such a situation
The dotted yellow line in the chart shows that jet streams can cause turbulence as well as bring strong winds. The turbulence can be rough on the edges of the jet stream. When crossing a jet stream at 90 degrees, this is especially true.
If the planned route of a flight will pass through an area with a severe forecast that could cause turbulence, pilots will often spot it during a preflight briefings. We would make a quick call to the flight planning to alert them to the threat and ask if there is another route that we can take.
Flight planners may be able to find a new route that avoids the worst of the turbulence if other airspace restrictions are included.
It is the same for forecasts. The Inter Tropical Convergence Zone is where we cross the equator. The only way for them to leave is up. These upward- moving winds are capable of forming storms that can reach 60,000 feet.
We can end up flying hundreds of miles off course. The flight route will avoid the area if storms are in the forecast.
There's no guarantee that storms won't develop along the route we are flying Accurate forecasts can help us avoid the worst areas.
Planes can fly in bad weather. A pilot says something.
No two days are the same as the routes that we fly. The winds are the main reason for a different route. Depending on where the jet streams are located, the route between London and Miami can be vastly different.
With strong jet streams in the middle of the Atlantic, the flight will most likely go down the northern Atlantic and then down the eastern seaboard. The return flight will be able to take advantage of the winds by flying across the pond.
It is possible to fly the London-to-Miami route out across the middle of the water if the jet streams are further north.
Each time we fly to a destination, the route will always be different in some way from the last time we visited due to high traffic density, geopolitics or weather.
All Rights Reserved © 2024
