At what altitude do scheduled planes fly? At what altitude do passenger planes fly?

Most “pioneers” of airspace are very worried before their first flight. Some are afraid of heights, others of speed, others “what if they fall,” and others are worried that there may not be enough air for everyone. In general, there are many reasons. The main thing, of course, is height. By and large, there is no reason to worry, because airplanes are the safest means of transportation in the world.

In this article we will talk about the altitude at which passenger aircraft fly, we will also provide information for comparing the altitudes of other aircraft, and we will also find out what the phrase “ideal altitude” means.

The height of a passenger aircraft varies from 10 to 12 km

Most people believe that the altitude of the aircraft is 10,000 meters. Perhaps, but in reality large passenger ships fly between 9 and 12 km above ground level.

The choice of the so-called “ideal” height is not random or universal for everyone. Each aircraft has its own defining level of flight, where fuel consumption is minimized and drag becomes small.

Important! The higher the plane rises, the lower the air density. Each vessel has its own passage corridor, and the ratio of friction force to the amount of air for combustion is optimal.

The effective altitude is not chosen by the ship's commander randomly, but solely based on the technical characteristics of the aircraft, where the middle ground between speed and fuel consumption is chosen. Actually, this is the answer to the question of why planes fly at an altitude of 10 km.

Airplane speed and altitude are related to each other

It should be noted that a large amount of fuel is consumed precisely at the moment of takeoff, which is why planes rise smoothly and at the same time quickly.

When the aircraft reaches the required values ​​in the airspace recommended by the controller, the seat belt light on board turns off and from that moment on it is allowed to unfasten the seat belts.

Flight Altitude Determination

The parameters of the most suitable routes vary from weather conditions, flight range and technical characteristics of the aircraft itself. As previously mentioned, the height of a passenger airliner ranges from 9 to 12 km. And here The dispatcher selects the ideal altitude for the aircraft based on weather conditions.

The rule is often used: aircraft that fly to the east, southeast, northeast - their corridor is at altitudes of 9 and 11 thousand meters above the ground; planes that fly towards the west, southwest and northwest - their corridor is 10 and 12 thousand meters.

Based on this, airline dispatchers determine which corridor will be most profitable for the airliner and report the flight level and flight level.

All air carrier dispatchers work in specially equipped headquarters and monitor all flights from takeoff to landing.

The radar screens show where the aircraft is, the state of its systems, the route and the atmosphere ahead. Moreover, dispatchers are constantly in touch with the aircraft and, if various problems arise, they try to quickly solve them.

There is an opinion that the maximum flight altitude of a passenger aircraft above the ground is above 12 km. This is not entirely true. It is rare that 12 km above ground level is exceeded. If the plane takes off above this level, it will simply begin to stall due to low air density. Also, at elevated altitudes, engine power decreases and fuel consumption begins to increase.

Heavenly roads

No matter how strange it may sound, roads in the sky also exist. And they are laid not only at certain levels from the ground, but also at the most convenient place for flights. Otherwise they are also called “jet routes”.

All countries issue permission to use airspace, and in the event of military operations or natural anomalies, part of the road is blocked. Also, this data is used when laying routes along with weather information, traffic control and regulation of their movement.

Airline dispatchers work in specially equipped headquarters

It is worth noting that in the sky every second simultaneously fly in different directions more than 5 thousand aircraft, and all of them are controlled by dispatchers. For example, if a ship needs to avoid a thunderstorm or turbulence, it can walk along the flight level, but the pilot is absolutely not allowed to change the corridor on his own without the consent of the dispatcher.

It is also worth noting that there is also movement along the corridors between aircraft; it must be at least 10 thousand meters - this is the so-called lateral separation. If this is an airport area, these are some corridors; if we are talking about long-distance routes, these are different.

You should also know that aircraft speed and altitude are interrelated. As was previously said, at different altitudes there is different air density, hence the change in resistance.

Since the airplane is an aerodynamic structure as such, its movement occurs through interaction with the air. At high altitudes, the density is less, the flow resistance weakens, and the lift force becomes less.

If you add some simple calculations, the picture will become clearer. For example, if an airplane has an optimal speed of 900 km/h, then it is profitable for it in terms of fuel consumption to fly at an altitude of 9-10 thousand meters above ground level. Financial savings come first for companies, but passenger safety and weather conditions are secondary.

Airplane altitude comparison

Traffic in the sky is just as intense as on regular roads. And if you watch in clear weather, you can see several planes flying simultaneously at different altitudes. This spectacle is undeniably mesmerizing. All that remains is to admire the precise calculations of the dispatchers and the professionalism of the pilots.

Looking from the window of a sky liner at the distant land below, at the pockmarked sections of fields, at the scattering of lights that are cities, you involuntarily ask the question: at what altitude does a passenger plane fly? We will try to answer this seemingly simple question. The thing is that the altitude that the airliner gains during flight is influenced by several factors. And the first of them is the car model. We often see planes in the sky. Some of them look like a sparkling star, leaving behind a gas trail. It is They who move across the sky silently. And there are also those airliners that, growling loudly and gutturally, fly so low that you can see the company emblem on the fuselage. Why is there such a difference in altitude gain during flight? Read about it below.

Ideal height. What it is

We remember from school science that the higher you rise, the thinner the atmosphere becomes. This also reduces the friction between the sides of the aircraft and the air. This means that the fuel consumption required to overcome atmospheric resistance is reduced. It would seem that all airliners should, based on this principle, fly at maximum altitude. Somewhere in the stratosphere, where there is almost no air at all, there is no friction. But the wings of airliners are designed so that the car is to some extent supported by air currents. And if they are not there, the plane begins to “collapse.” That's why pilots talk about the ideal corridor. This is the space between nine and twelve thousand meters above the ground. At what altitude a passenger aircraft of a given design flies is calculated by the pilot, based on its technical characteristics. This should be the “golden mean” between friction and maintaining the car with air masses.

Route direction

It may seem strange that the factor that influences how high a passenger plane flies is its route. In order to prevent airliners from colliding in the sky (after all, no one would survive such an accident), the controllers established the following rule. All eastbound aircraft, with various diversions to the south or north, occupy odd-numbered air lanes. This is usually nine and eleven kilometers from the surface of the earth. And liners flying west travel in even “ranges” of altitudes (ten and twelve thousand meters). Based on the technical parameters of the machine, pilots calculate which corridor to choose and report this to ground controllers. And they are already warning the ship’s crew about meteorological conditions along the route. Sometimes, in order to avoid, the airliner has to decrease or gain altitude. Dispatchers control the entire course of the aircraft and maintain continuous communication with the pilot.

Some countries close airspace over their territory (or part of it) due to armed conflicts. High mountains cause turbulence at altitude. The pilot must take all these reasons into account when planning a route. The path of the aircraft, agreed upon with the dispatchers, as well as the average altitude at which the flight will be carried out, is called the “flight level”. But natural disasters in the form of high ones cannot be foreseen in advance. Extensive cloud cover leads to great turbulence. And the pilot should go around the clouds to avoid danger. And it’s better to do this on top, where no vagaries of the weather are scary. The maximum depends only on the type of machine. For example, the TU-204 can rise only to 7200 m. The new IL-62 - to eleven kilometers. The Airbus A310 has the same maximum altitude. What plane can fly twelve kilometers into the sky? These are cars with jet engines. The Boeing 737-400 is capable of climbing to the highest height from the passenger sides.

The largest amount of fuel is consumed when the aircraft takes off. After all, a heavy car must accelerate well in order to get off the ground and gain altitude, overcoming strong air friction. Therefore, despite the altitude at which a passenger plane flies, the ascent occurs as quickly as possible. Passengers are then told to fasten their seat belts as the plane reaches cruising speed. For the Boeing 737-400, this technical characteristic is almost eight hundred kilometers per hour. When the plane reaches its mid-altitude, the cabin announces that the seat belts can be removed.

Rising into the sky, we often want to look out the window at the Earth remaining far below, but we only see clouds. Surely, every passenger, at such moments, wondered at what altitude passenger planes fly, and why...

Having barely gained altitude, the long-awaited sound comes from the speakers: “The captain greets you, we are at ten thousand km, overboard - minus fifty, you can unfasten your seat belts, they will soon feed you...” But whether the pilot said the truth is known only to him. After all, in fact, most airliners do not fly at a fixed altitude, but in the range between 9 and 12 km.

What determines the flight altitude of a passenger aircraft?

The choice of flight level (the conventional altitude at which the flight takes place) is determined by many factors. First of all, these are technical characteristics and. The weather, duration and even direction of the flight also play a role. According to the rules of vertical separation, flights heading west occupy an even altitude (30, 32, 34 thousand feet, for example), and those moving to the East occupy an odd altitude (31, 33, 35 thousand feet).

The altitude at which the plane flies depends not on the captain, but on the air traffic control service. It is she who calculates the optimal altitude for each flight. In emergency situations (danger or thundercloud on the course), pilots are required to coordinate their actions with the dispatcher. By trying to bypass an obstacle without authorization, you can go beyond the boundaries of your flight level and create a threat of collision with another aircraft.

Why do passenger planes fly at an altitude of 10,000 meters?

As we found out, the optimal flight level is different for all flights, and 10 thousand meters is the average flight altitude of a passenger aircraft. Why exactly this figure? There are several reasons for this.

1. The higher the altitude, the lower the air density. Accordingly, drag is reduced, and hence fuel consumption. However, after 12,000 m the situation changes: the air becomes too thin and there is not enough oxygen to burn fuel, which is why the plane begins to “fail.”
2. Modern jet engines require powerful cooling. -50°C outside is ideal for this.
3. A rare bird will fly to the middle of the Dnieper at an altitude of 10,000 meters. The lack of birds is another reason why planes fly at high altitudes.
4. Flying above the clouds, the plane is not so dependent on weather conditions and phenomena such as thunderstorms, rain, snow, hail...
5. In the event of an emergency, pilots have more time to make decisions and perform the necessary maneuvers to ensure safety than at an altitude of 2,000 m, for example.

It should be noted that all of the above is true for most modern international airliners, the cruising speed of which does not exceed 1000 km/h. However, in the near future we will see ultra-high-speed flights, for which 10,000 m will not be the limit. Then the answer to the question at what altitude passenger planes fly will be somewhat different...

According to what principles are planes moved along routes? What is the flight altitude of a passenger plane? Why do pilots choose certain parameters for moving in space? To answer the questions presented, you need to consider the following information.

The concept of “ideal” height

The average flight altitude of a passenger aircraft ranges from 9 to 12 thousand meters above sea level. Pilots resort to setting it up because in such conditions there is less resistance on the body of the aircraft, which means this has its pros and cons at the same time. Under such conditions, aircraft engines consume less fuel. However, engines lack oxygen, which is required to burn fuel. Therefore, when the flight altitude of a passenger aircraft reaches the maximum permissible values, the engine power drops somewhat. As practice shows, reaching maximum altitudes is accompanied by wasteful fuel consumption.

Based on the above, experienced pilots choose the “ideal” altitudes. Choosing the so-called golden mean promotes the fastest possible movement of a passenger aircraft, as well as saving fuel.

Security Considerations

The average passenger aircraft flight altitude of 10,000 meters is chosen partly for safety reasons. Why do pilots stop at this value? There are several reasons for this:

1. High-power jet engines of modern passenger aircraft quickly heat up to critical values. Therefore, there is an urgent need for high-quality cooling, which makes it possible to avoid fires. The temperature outside at an altitude of 10,000 meters above sea level reaches values ​​of the order of -50 o C. Such conditions are ideal for cooling engines naturally.
2. Birds are not able to climb to these heights. The absence of birds that can crash into windows, the skin of an aircraft or get into engines at significant speed is the key to safe flights.
3. If the flight altitude of a passenger aircraft is 10-12 thousand m, the aircraft is not exposed to rain, snow, thunderstorms, or other natural phenomena, since the board is located above the cloud formation area.
4. Flights at significant altitudes are carried out due to the likelihood of emergency situations, for example, deviation from the course, engine fires, failure of on-board systems, loss of communication with dispatchers. Being 10,000 m from the ground gives pilots more time to think, perform the necessary maneuvers and make the right decisions.

Route requirements

Oddly enough, the sky has its own routes for individual flights. They lie at high altitudes. Thus, in the event of armed clashes on the territory of certain countries over which the plane flies, passengers will be relatively safe. The organization of routes at separate altitudes ranging from 9 to 12 thousand kilometers also avoids space congestion and accidental aircraft collisions.

Finally

So we figured out what flight altitude of a passenger aircraft is considered optimal. The determination of routes for the movement of aircraft is carried out at airline headquarters. Here they monitor the progress of their movement and make the necessary adjustments. Therefore, individual aircraft may change their altitude during the flight.

The boundary between the Earth's atmosphere and space runs along the Karman line, at an altitude of 100 km above sea level.

Space is very close, do you realize?

So, the atmosphere. An ocean of air that splashes above our heads, and we live at its very bottom. In other words, the gas shell, rotating with the Earth, is our cradle and protection from destructive ultraviolet radiation. Here's what it looks like schematically:

Troposphere. Extends to an altitude of 6-10 km in polar latitudes, and 16-20 km in the tropics. In winter the limit is lower than in summer. The temperature drops with altitude by 0.65°C every 100 meters. The troposphere contains 80% of the total mass of atmospheric air. Here, at an altitude of 9-12 km, passenger planes fly aircraft. The troposphere is separated from the stratosphere by the ozone layer, which serves as a shield that protects the Earth from destructive ultraviolet radiation (absorbs 98% of UV rays). There is no life beyond the ozone layer.

Stratosphere. From the ozone layer to an altitude of 50 km. The temperature continues to drop and, at an altitude of 40 km, reaches 0°C. For the next 15 km the temperature does not change (stratopause). They can fly here weather balloons And *.

Mesosphere. Extends to an altitude of 80-90 km. The temperature drops to -70°C. They burn in the mesosphere meteors, leaving a luminous trail in the night sky for several seconds. The mesosphere is too rarefied for aircraft, but at the same time too dense for artificial satellite flights. Of all the layers of the atmosphere, it is the most inaccessible and poorly studied, which is why it is called the “dead zone.” At an altitude of 100 km there is the Karman line, beyond which open space begins. This officially marks the end of aviation and the beginning of astronautics. By the way, the Karman line is legally considered the upper limit of the countries located below.

Thermosphere. Leaving behind the conditionally drawn Karman line, we go out into space. The air becomes even more rarefied, so flights here are only possible along ballistic trajectories. Temperatures range from -70 to 1500°C, solar radiation and cosmic radiation ionize the air. At the north and south poles of the planet, solar wind particles entering this layer cause visible light at low latitudes of the Earth. Here, at an altitude of 150-500 km, our satellites And spaceships, and a little higher (550 km above the Earth) - beautiful and inimitable (by the way, people climbed to it five times, because the telescope periodically required repairs and maintenance).

The thermosphere extends to an altitude of 690 km, then the exosphere begins.

Exosphere. This is the outer, diffuse part of the thermosphere. Consists of gas ions flying into outer space, because. The force of gravity of the Earth no longer acts on them. The exosphere of the planet is also called the “corona”. The Earth's "corona" is up to 200,000 km high, which is about half the distance from the Earth to the Moon. In the exosphere they can only fly unmanned satellites.

*Stratostat – a balloon for flights into the stratosphere. The record height for lifting a stratospheric balloon with a crew on board today is 19 km. The flight of the stratospheric balloon “USSR” with a crew of 3 people took place on September 30, 1933.

**Perigee is the point of the orbit of a celestial body (natural or artificial satellite) closest to Earth.
***Apogee is the most distant point in the orbit of a celestial body from the Earth