What is the percentage of the air at high altitudes. What is the percentage of the air at high altitudes Why at an altitude of 10 km minus 50

Going on a trip by plane, leaving behind the not most comfortable moment of take-off, the passenger finds himself in sky-high heights in a matter of minutes. With a clear sky, through the window of the plane, you can see pieces of land floating far below, in cloudy weather, the plane is above the clouds, which also float somewhere under it.

At what height do they fly passenger aircraft? After take-off, it is often announced that the aircraft is at an altitude of 10 km. An inquisitive person probably has a question - why are flights performed at such a height, why is it better than others?

How high do the planes fly?

10 km altitude is an average. As a rule, we are talking about a range within 9-12 kilometers, where the courses of the aircraft that carry passengers are laid. Moreover, it is not the pilot who chooses the altitude. The issue is decided by the dispatcher, it is he who calculates the altitude for each individual flight. The pilot must listen to all dispatcher's manuals and follow them exactly. Otherwise, there is a risk of collision with other sides - this is extremely rare, but it does happen.

: aircraft can climb to an altitude of over 37 kilometers. But we are not talking about civilian aircraft, but about interceptor fighters. They have completely different technical indicators.

Altitude and air performance

Height and pressure

It is known that the air is rarefied at high altitudes. This is due to a simple circumstance. The planet's atmosphere is held by its gravity. This force manifests itself most powerfully at the surface, holding the planet's air envelope, providing it with maximum density precisely in the lower layers. The higher, the weaker the air pressure. The pressure increases closer to the surface from the weight of the upper layers of the air, as in the ocean the pressure increases due to the upper layers of water. The aircraft and its flight performance strongly depend on the air performance, primarily on its density.

Related materials:

Why does it stick its ears on the plane?

Air is needed to provide lift, for normal work engines. It is worth remembering that without oxygen, the combustion process does not occur, the engine stalls. If the density is low, this is bad, but too much is not needed either. Optimal conditions for civil aircraft are observed at an altitude of 10 km, in the air corridor from 9 to 12 km, depending on weather and other conditions.

Too much density is not needed for the reason that it does not allow the required speed to be developed. Dense air masses slow down the movement of an aircraft in the same way that water slows down the movement of a swimmer. Each person noticed that in water it is impossible to be as fast and dexterous as on land. This is due to the higher density of the aqueous medium compared to the air.

Related materials:

Why are the plane windows round?

A similar difference, not so pronounced for a person, but very noticeable for an airplane that moves at a speed of several hundred kilometers per hour, is also observed between air masses at different heights. In addition to the problems with the development of speed, flying at low altitude brings high fuel costs, while when traveling in more rarefied air masses, less fuel is spent. These are interconnected phenomena - in order to move in a denser space, more energy is required, and therefore more fuel.

Related materials:

How do planes land in heavy fog and rain?

Optimal heights

The air density within such limits remains sufficient to keep an aircraft flying from specified speed... At higher altitudes, a greater speed is required. So, when flying at an altitude of 12-15 km, a civilian plane could only move at supersonic speeds, otherwise the air masses would not be able to keep it on the fly.

Modern design characteristics of civil aircraft make this height optimal for them. However, they may well fly at other heights, if necessary, slightly higher or much lower. But this is irrational and can be dangerous. Pilots of civil flights are responsible for the lives of hundreds of people on board, there is no reason for them to risk it, it would be irresponsible. Therefore, they adhere to the limits set by them, and the dispatcher seeks to navigate each of the aircraft in the safest and most rational way for him.

Related materials:

Why do passenger planes have two or four engines?

Thus, an altitude of 10 km is optimal for civil aircraft due to air density and other indicators. environment typical for such heights. This is the most rational, economical, safe, comfortable altitude, within which the entire main path of the aircraft passes, excluding the moments of its takeoff and landing, or emergency situations associated with oncoming flights in the corridor, weather conditions, and other circumstances when pilots are forced to fly higher or below.

If you find an error, please select a piece of text and press Ctrl + Enter.

• Why swallows before the rain ...

Most of the "pioneers" of airspace are very worried before the first flight. Some are frightened by the height, others by the speed, the third “what if it falls,” the fourth worry that there may not be enough air for everyone. In general, there are many reasons. The main one, of course, is, nevertheless, the 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 at what altitude passenger aircraft fly, we will also provide information for comparing the heights of other aircraft, as well as find out what the phrase "ideal altitude" means.

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

Most people assume that the height of the aircraft is 10,000 meters. Possibly, but really large passenger ships fly from 9 to 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 flight level, where fuel consumption is minimized and drag becomes small.

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

The effective height is not chosen by the ship commander by chance, but solely based on technical characteristics aircraft, where the middle between speed and fuel consumption is chosen. Actually, this is the answer to the question 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 the aircraft smoothly and simultaneously quickly rise upward.

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

Determination of flight altitude

The parameters of the most suitable routes range from weather conditions, range and technical characteristics of the aircraft itself. As mentioned earlier, the height of a passenger liner ranges from 9 to 12 km. But the controller chooses the ideal altitude for the aircraft based on weather conditions.

The rule is often used: aircraft flying to the east, southeast, northeast - their corridor at heights of 9 and 11 thousand meters above the ground; aircraft flying towards the west, south-west and north-west - their corridor is 10 and 12 thousand meters.

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

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 corridor and the atmosphere ahead. Moreover, dispatchers are constantly in touch with the aircraft and, when various problems arise, they try to quickly solve them.

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

Heavenly roads

As strange as it may sound, roads in the sky also exist. And they are laid not only at certain levels from the ground, but also along the most convenient place for flights. Otherwise, they are also called "reactive routes".

All countries issue permits for the use of airspace, and in the event of hostilities or natural anomalies, a part of the road is blocked. Also, this data is used when laying routes along with meteorological information, traffic control and regulation of their following.

Air carrier dispatchers work in specially equipped headquarters

It should be noted that in the sky every second simultaneously fly in different directions more than 5 thousand aircraft, and they are all controlled by dispatchers. For example, if it is necessary for a ship to bypass a thunderstorm or turbulence, it can walk along the flight level, but the pilot cannot change the corridor on his own without the dispatcher's consent.

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 the same corridors when it comes to routes long distance- other.

You should also be aware that aircraft speed and altitude are related to each other. As mentioned earlier, air density is different at different altitudes, hence the change in resistance.

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

If you include simple calculations, the picture will be clearer. For example, if the plane optimal speed 900 km / h, it is beneficial for him in terms of fuel consumption to fly at an altitude of 9-10 thousand meters above ground level. Financial savings are in the first place for companies, but the safety of passengers and weather conditions are already secondary.

Comparison of aircraft heights

Traffic in the sky is as heavy as on normal roads. And if you watch it in clear weather, you can see how several planes fly at different heights at the same time. This spectacle is undeniably mesmerizing. We can only admire the precise calculations of the dispatchers and the professionalism of the pilots.

Useful Tips

In the light of the regular creepy news about plane crashes, people who are not related to air travel unwittingly ponder about safety flights . Questions arise, the answers to which cannot be found anywhere.

What is an oxygen mask for? Which is more dangerous - takeoff or landing? Answers for you experienced professional pilot, flight and technical training Captain Dave Thomas, working in British Airways.

Flight safety

Millions of passengers around the world fear the thought of flying. And in some extreme cases, this feeling makes you completely abandon travel. Are these fears justified? Let's figure it out.

Are flights safer now than 10-20 years ago?

Flights on modern jet aircraft currently have high degree of security.

According to statistics, since 2009, accidents per 1 million flights 4 times less. The entire flight system is primarily focused on improving the safety of air transportation.

What is the risk that the plane will crash?

Chances are that the plane you are traveling on will crash scanty. You are much more likely to crash in the car that takes you to the airport.

International Air Transport Association statistics show that the number of accidents in world aviation constantly falling year after year.

It should be noted that airlines do not rest on their laurels and work tirelessly to organize the safest flights possible.

Is the turbulence zone dangerous?

This may be the main thing that worries nervous travelers who are horrified by the slight shaking and the announcement of the wearing of a seat belt. But there is really nothing to worry about.

In the turbulence zone, passengers feel discomfort, but this not dangerous. However, always better to follow safety tips and fasten your seat belt to avoid potential minor injuries.

The captain of the airship must consult passengers in any turbulence as additional measure security.

Why do passenger planes fly at an altitude of 10 km?

This height is a kind of compromise between engine efficiency and aerodynamics for jet aircraft.

Modern gas turbine engines operate more effective at an altitude of about 10 km, in contrast to turboprop aircraft (mixture gas turbine and propeller), which need a lower height (6-8 km).

Which is more risky - takeoff or landing?

Both takeoff and landing are maneuvers requiring the pilot to high level of skill. Therefore, special state organizations(and first of all the airlines themselves) are very strictly select staff and train pilots on modern simulators, which helps them to hone their aircraft control skills to the maximum.

Additional skills and procedures are required for maneuvering at some airports and during inclement weather. But thanks to modern simulators, pilot training is becoming much more effective than it used to be.

Why are there no parachutes on planes?

Pilots are taught to land in the event of a malfunction. It is much safer and more practical. In addition, it is extremely difficult (even impossible) to competently organize an emergency landing of passengers by means of parachutes.

Why don't civilian planes fly over military zones?

Airlines work closely with government (and not only) security agencies to ensure that civil aircraft did not fly over dangerous war zones.

This was the case with Malaysian Airlines (board MH17) last July, when 298 people died. The airline allowed its aircraft to fly in the war zone, underestimating the risks in the conflict zone.

The local aviation authorities make an assessment and recommendation, which is then passed on to a NOTAM (Notice to Pilots). And airlines, in turn, choose what to do.

Airplane safety

Where does the water in the toilet of an airplane go?

What is a black box?

The black box is actually orange in color. It contains recording device, on which all the conversations of the pilots are saved.

Modern aircraft also have so-called QARs or Quicks - recorders that record even more information than is usually needed.

Why are passengers being told to close the window shades during boarding?

This is done so that the person was not blinded and got used to more light outside the plane.

The announcement of the closing of the window shades is exclusively advisory character and ensures the comfort of passengers.

Why do oxygen masks fall out?

Airplane oxygen masks are enough smart mechanism which determines the need for a mask by monitoring the pressure inside the aircraft. Oxygen masks can automatically deploy. There is also a separate button on board that does the same.

How often are pilots' knowledge tested?

Professional pilots are one of the highest paid professions, and therefore require regular recertification.

All pilots are checked on a special simulator within two days. every six months. They are also tested in "live" flight once a year.

A training course for a new type of aircraft may take from three weeks to three months, depending on whether the pilot has flown such aircraft or not. Reputation is very important for any airline, so flight safety is always a top priority.

What is the safest seat on the plane?

All passenger seats have very high safety standards. In addition, according to statistics, airliners are the safest mode of transport in the world.

In Egypt, on November 3, decryption of the "black boxes" of the crashed Russian plane began. Local journalists, however, had reported a day before that, judging by the information on the flight recorders, the liner crew had not requested an emergency landing from the air traffic controllers, and that no external influence had been exerted on the liner. Soon, the news was also disseminated that four minutes before the tragedy, "sounds uncharacteristic for a regular flight" allegedly appeared on board. Meanwhile, the Federal Air Transport Agency is asked to refrain from any conclusions before the official results of the investigation are announced.

We discussed the situation on the air of Radio Komsomolskaya Pravda with the current navigator, Sergei Kudryashov.

"Before each flight, the plane tests itself."

- What is the probability that the crew, knowing about the aircraft malfunctions, can abandon the flight? Will the crew sit on the faulty plane?

The probability is zero. Crews who fly civil aircraft will never take on responsibilities that they don't need. This is the first thing. The second is the level state of the art equipment that is now used by airlines. Aircraft of Airbus Industrie are equipped with multiple internal control all systems. Including, before each flight, the aircraft tests itself and issues a special listing - that is, it prints the state of the systems and indicates which of them and in which state.

Sergey Kudryashov - on the crash of a Russian plane

In addition, there are also remote warning systems. The plane itself warns the company that it is defective. Telemetry information is sent to the airline itself via the communication line. This is independent of the technical staff. And in accordance with this, everyone already knows perfectly well that the plane is in a non-flying state. If there is an external destruction of the structure on the ground, it means that some structural elements that are clearly visible are torn off, the flight crew is watching this, which bypasses the aircraft and carefully looks at its condition. In addition, there are ground control systems. I mean human - mechanics bypass, look, refuel. Visual inspection is constantly carried out for the integrity of the aircraft structure.

A defective plane cannot fly. In accordance with this, you also need to ask yourself a question, every pilot has a family, have children, you need to earn money, and not be a kamikaze in order to make violation after violation, to try to fly on something that cannot fly in principle. I think this version should be excluded from consideration.

"Skills are cut into the crew with an ax"

- How long does it take to inform dispatchers about a change in the situation?

The crew that flies on airplanes such as Airbus, Boeing, on our planes - on the Il-96, on others - these are people who have gone through a very, very serious school. Skills are cut into them with an ax. In accordance with the need, they immediately give out those necessary actions that they can perform. If something happened to the plane, first there is an assessment of the condition - you need to figure out what is happening. Some signal boards start blinking or messages appear on the screens of displays, multifunction indicators that are in the cab. Or flashing warning signals appear. You need to understand them. It takes a while. If we have decided that there are problems on board, and the plane is flying normally, but we are analyzing the signaling situation, then it is necessary to issue a voice message or a radio message that we have problems on board. Mayday - the so-called SOS. In order to issue even this command, you need to consciously press the buttons several times so that the command goes on the air and that the ground services accept this command and prepare to rescue the plane. The next decision was made that we will land the plane at the nearest airfield under the control of air traffic control specialists who will guide us and direct our approach. A whole range of actions to be taken.

In this case, which happened, nothing was done. The plane immediately went into an uncontrollable fall. Now some experts say: he went into a tailspin. A corkscrew is an aerodynamic figure that is described by certain laws. In this case, this was not the case. There was an indiscriminate fall, which resulted in the plane crashing to the ground in an already overturned state. And, consequently, such a catastrophic phenomenon occurred on board, which did not allow the crew to take a single action, which is prescribed by the manual for the flight operation of the aircraft and actions in special conditions.

"There is a version that an explosive decompression of the aircraft took place."

- Apparently, they died instantly?

They either died instantly, or were in such conditions that they immediately had to fight for the survivability of the aircraft, rescue passengers, and act by all means available to them in order to prevent a catastrophic development of the situation.

- There was information that before the airliner disappeared from the radar screens, sounds uncharacteristic for a regular flight appeared on the recording from the cockpit. What could it be?

Here you need to wait for the decoding of the voice recorder, which records all the sounds that occurred during radio exchange, during negotiations inside the cabin, during negotiations between the cockpit and the passenger compartment. All sounds were recorded there. To say that something has appeared, that something has happened there ... You and I will not be able to assess exactly what happened in this situation.

A version was published today that experts admit that an explosive decompression of the aircraft took place. That is, practically the pressure that was in the cockpit was completely equal to the atmospheric pressure at an altitude of 10 thousand meters.

When we fly with you, we have atmospheric pressure in the cockpit, which we are used to breathing, and at 10 thousand meters there was an instant depressurization, which led to the fact that we immediately lost the pressure habitual for the life of people. This suggests that it happened immediately, in a fraction of a second. And the entire composition that was on the plane, he was already immobilized, at least.

ANOTHER OPINION

"People fantasize"

The news about "uncharacteristic sounds" on board was also commented on by the former pilot, flight safety specialist Alexander Romanov on the radio "Komsomolskaya Pravda". The expert believes that it is impossible to trust any information now - you need to wait for official statements.

Alexander Romanov - about stuffing in the media

I think this is completely false information. Because the first information was that the pilots reported a failure of the equipment. They also wrote that groans were heard from under the rubble. It's all some kind of another duck or stuffing. People sometimes fantasize, you know, ”the specialist warned. - It seems to me that the boxes have not been decrypted yet. Because the commission has not been finally formed, and without it they cannot be opened.

We express our condolences to the families and friends of those killed in the plane crash.

Exclusive VGTRK from the crash site: what he saw causes chills. The wreckage of a Russian plane that crashed in Egypt is scattered over an area of ​​about 30 square kilometers, said on the air of the TV channel "Russia24"

With the rise to a height, atmospheric air is thinned, and the speed of its movement increases sharply. Air temperature within the troposphere (up to 5 -18 km) decreases on average by 0.65 ° for every 100 m lifting to a height. At a height of 10 km from the surface of the earth, the air temperature reaches -55 °, and at an altitude of 30 km -92 °. From height 5 km the air contains practically no water vapor. Dry air with a low temperature has a great cooling capacity and requires good thermal protection of a person.

Ascent to a height of 3500 m (pressure 493 mm rt. Art.) tolerated by most people satisfactorily with increased activity of the cardiovascular, respiratory and other systems. Above 4000 m the majority of healthy people develop oxygen deficiency (hypoxia), which, as it deepens, manifests itself in a number of disorders, united under the general name of "high-altitude" illness.

The aircraft are equipped with pressurized cabins, in which temperature, humidity and air pressure are maintained at a given level.

During long flights at altitude, the air pressure in pressurized cabins is artificially maintained at 634 mm rt. Art., which corresponds to the pressure in an open atmosphere at an altitude of 1500 m.

Emergency depressurization of the aircraft cabin at high altitudes can lead to decompression sickness, which is a consequence of the release of gases (mainly nitrogen) from tissues and body fluids when the barometric pressure drops rapidly. It manifests itself as pain around the joints, itching, nausea, and vomiting. Fainting may occur. Other decompression disorders include otitis media (aerootitis), inflammation of the frontal and other sinuses, and flatulence in the intestines (high-altitude flatulence).

The pilot is protected from the effect of a sudden drop in pressure when the cabin is depressurized by supplying oxygen through an oxygen device throughout the flight and using a pressure helmet or high-altitude spacesuit (Fig. 146).

A change in the speed or direction of flight (acceleration 1) causes mechanical stresses in the human body, which are called overloads. The greater and longer the overload, the more stress the body experiences. Overloads cause mechanical displacement of the moving parts of the body (mainly blood). If the external force, which is the cause of acceleration, acts in the direction from the legs to the head, it is customary to speak of positive acceleration (ejection, Nesterov's loop). The action of the force in the opposite direction (from the head to the feet) causes negative acceleration (spin). Acceleration, direction