How the plane lands. Let's open the curtain. How do planes land? Airplane landing definition

Those who live in the area of airports know that most often taking off liners soar up a steep trajectory, as if trying to get away from the ground as soon as possible. Indeed, the closer the earth, the less the ability to respond to an emergency and make a decision. Landing is another matter.

A 380 lands on a runway covered with water. Tests have shown that the aircraft is capable of landing in crosswinds with gusts up to 74 km/h (20 m/s). Although FAA and EASA regulations do not require reverse braking devices, Airbus designers decided to equip two engines closer to the fuselage with them. This made it possible to obtain an additional braking system, while reducing operating costs and reducing preparation time for the next flight.

A modern jet passenger liner is designed to fly at altitudes of approximately 9-12 thousand meters. It is there, in very rarefied air, that it can move in the most economical mode and demonstrate its optimal speed and aerodynamic characteristics. The interval from the completion of the climb to the beginning of the descent is called cruise flight. The first stage of preparation for landing will be the descent from the flight level, or, in other words, following the arrival route. The final point of this route is the so-called initial approach checkpoint. In English, it is called Initial Approach Fix (IAF).

From the IAF point, movement begins according to the approach to the aerodrome and landing approach, which is developed separately for each airport. The approach according to the scheme involves further descent, passing the trajectory set by a number of control points with certain coordinates, often making turns and, finally, reaching the landing straight. At a certain point on the landing straight line, the liner enters the glide path. Glide path (from French glissade - glide) is an imaginary line connecting the entry point to the start of the runway. Passing along the glide path, the aircraft reaches the MAPt (Missed Approach Point), or go-around point. This point is passed at the decision altitude (CLL), i.e. the height at which the go-around maneuver should be initiated if, prior to reaching it, the pilot-in-command (PIC) did not establish the necessary visual contact with landmarks to continue the approach. Before the PLO, the PIC should already assess the position of the aircraft relative to the runway and give the command “Sit down” or “Leave”.

Chassis, flaps and economics

On September 21, 2001, an Il-86 aircraft belonging to one of the Russian airlines landed at Dubai Airport (UAE) without releasing the landing gear. The case ended in a fire in two engines and the decommissioning of the liner - fortunately, no one was hurt. There was no question of a technical malfunction, just the chassis ... they forgot to release it.

Modern liners, compared to aircraft of past generations, are literally packed with electronics. They implement a fly-by-wire electrical remote control system (literally “fly on the wire”). This means that the rudders and mechanization are set in motion by actuators that receive commands in the form of digital signals. Even if the aircraft is not flying in automatic mode, the movements of the steering wheel are not directly transmitted to the rudders, but are recorded in the form of a digital code and sent to a computer that will instantly process the data and give a command to the actuator. In order to increase the reliability of automatic systems, two identical computer devices (FMC, Flight Management Computer) are installed in the aircraft, which constantly exchange information, checking each other. In FMC, a flight task is entered with the indication of the coordinates of the points through which the flight path will pass. Electronics can guide the aircraft along this trajectory without human intervention. But the rudders and mechanization (flaps, slats, spoilers) of modern liners are not much different from the same devices in models released decades ago. 1. Flaps. 2. Interceptors (spoilers). 3. Slats. 4. Ailerons. 5. Rudder. 6. Stabilizers. 7. Elevator.

Economics is at the heart of this accident. The approach to the airfield and landing approach are associated with a gradual decrease in the speed of the aircraft. Since the amount of wing lift is directly related to both speed and wing area, in order to maintain enough lift to keep the car from stalling into a tailspin, the wing area needs to be increased. For this purpose, mechanization elements are used - flaps and slats. Flaps and slats perform the same role as the feathers that birds fan out before falling to the ground. Upon reaching the speed of the start of the release of mechanization, the PIC gives the command to extend the flaps and almost simultaneously - to increase the engine operation mode to prevent a critical loss of speed due to an increase in drag. The greater the deflection angle of the flaps/slats, the greater the mode required by the engines. Therefore, the closer to the runway the final release of mechanization (flaps / slats and landing gear) takes place, the less fuel will be burned.

On domestic aircraft of old types, such a sequence for the release of mechanization was adopted. First (for 20-25 km to the runway) the chassis was produced. Then for 18-20 km - flaps at 280. And already on the landing straight, the flaps were fully extended, into the landing position. Today, however, a different methodology has been adopted. In order to save money, pilots tend to fly the maximum distance “on a clean wing”, and then, before the glide path, reduce speed by intermediate flap extension, then extend the landing gear, bring the flap angle to the landing position and land.

The figure shows a very simplified approach to landing and takeoff in the airport area. In fact, the schemes can differ markedly from airport to airport, as they are drawn up taking into account the terrain, the presence of high-rise buildings near and no-fly zones. Sometimes there are several schemes for the same airport depending on weather conditions. So, for example, in the Moscow Vnukovo, when entering the runway (VVP 24), the so-called. a short circuit, the trajectory of which lies outside the Moscow Ring Road. But in bad weather, planes enter in a long pattern, and the liners fly over the South-West of Moscow.

The crew of the ill-fated IL-86 also used the new technique and extended the flaps to the landing gear. Knowing nothing about the new trends in piloting, the Il-86 automation immediately turned on the voice and light alarm, which required the crew to release the landing gear. So that the signaling would not irritate the pilots, it was simply turned off, just as a boring alarm clock is turned off when awake. Now there was no one to remind the crew that the chassis still needed to be released. Today, however, instances of the Tu-154 and Il-86 aircraft with modified signaling have already appeared, which fly according to the approach method with a late release of mechanization.

Based on actual weather

In information reports, you can often hear a similar phrase: "Due to the deterioration of weather conditions in the area of airport N, crews make decisions about takeoff and landing based on the actual weather." This common stamp causes domestic aviators to laugh and indignant at the same time. Of course, there is no arbitrariness in the flying business. When the aircraft passes the decision point, the aircraft commander (and only he) finally announces whether the crew will land the liner or the landing will be aborted by a go-around. Even under the best weather conditions and the absence of obstacles on the runway, the PIC has the right to cancel the landing if, as the Federal Aviation Rules say, he is "not sure of the successful outcome of the landing." “Go-around today is not considered a miscalculation in the work of the pilot, but on the contrary, it is welcomed in all situations that allow for doubt. It is better to be vigilant and even sacrifice some amount of burned fuel than put the lives of passengers and crew at even the slightest risk,” explained Igor Bocharov, Head of Flight Operations at S7 Airlines.

The course-glide path system consists of two parts: a pair of course and a pair of glide path radio beacons. Two localizers are located behind the runway and radiate a directional radio signal along it at different frequencies at small angles. On the runway center line, the intensity of both signals is the same. To the left and to the right of this direct signal of one of the beacons is stronger than the other. By comparing the intensity of the signals, the aircraft's radio navigation system determines on which side and how far it is from the center line. Two glide path beacons stand in the area of the touchdown zone and act in a similar way, only in a vertical plane.

On the other hand, in making decisions, the PIC is strictly limited by the existing rules of the landing procedure, and within the limits of this regulation (except for emergency situations like a fire on board), the crew does not have any freedom of decision-making. There is a strict classification of approach types. For each of them, separate parameters are prescribed that determine the possibility or impossibility of such a landing under given conditions.

For example, for Vnukovo Airport, a non-precision instrument approach (according to locators) requires passing a decision point at an altitude of 115 m with a horizontal visibility of 1700 m (determined by the meteorological service). To land before the VLOOKUP (in this case, 115 m), visual contact with landmarks must be established. For an automatic landing according to ICAO category II, these values are much lower - they are 30 m and 350 m. Category IIIc allows a fully automatic landing with zero horizontal and vertical visibility - for example, in complete fog.

Safe hardness

Any air passenger with experience in flights by domestic and foreign airlines has probably noticed that our pilots land planes “softly”, while foreign ones land “hard”. In other words, in the second case, the moment of touching the strip is felt in the form of a noticeable push, while in the first case, the aircraft gently “grinds” to the strip. The difference in landing style is explained not only by the traditions of flight schools, but also by objective factors.

Let's start with some terminological clarity. A hard landing in aviation is called a landing with an overload that greatly exceeds the standard. As a result of such a landing, the aircraft, at worst, suffers damage in the form of permanent deformation, and at best, requires special maintenance aimed at additional control of the condition of the aircraft. As Igor Kulik, Leading Pilot Instructor of the Flight Standards Department of S7 Airlines, explained to us, today a pilot who made a real hard landing is removed from flights and sent for additional training in simulators. Before going on a flight again, the offender will also have to test-training flight with an instructor.

The landing style on modern Western aircraft cannot be called hard - it's just about increased overload (about 1.4-1.5 g) compared to 1.2-1.3 g, characteristic of the "domestic" tradition. In terms of piloting technique, the difference between landings with relatively less and relatively more g-loads is explained by the difference in the procedure for leveling the aircraft.

To leveling, that is, to prepare for touching the ground, the pilot proceeds immediately after passing the end of the runway. At this time, the pilot takes over the helm, increasing the pitch and transferring the aircraft to the pitching position. Simply put, the aircraft "turns its nose", which results in an increase in the angle of attack, which means a small increase in lift and a drop in vertical speed.

At the same time, the engines are transferred to the “idle gas” mode. After some time, the rear landing gear touches the strip. Then, reducing the pitch, the pilot lowers the front strut onto the runway. At the moment of contact, spoilers (spoilers, they are also air brakes) are activated. Then, reducing the pitch, the pilot lowers the front strut onto the runway and turns on the reverse device, that is, additionally slows down with engines. Wheel braking is applied, as a rule, in the second half of the run. The reverse is structurally made up of shields that are placed in the path of the jet stream, deflecting part of the gases at an angle of 45 degrees to the course of the aircraft - almost in the opposite direction. It should be noted that on aircraft of old domestic types, the use of reverse during the run is mandatory.

Silence on the sidelines

On August 24, 2001, the crew of an Airbus A330 flying from Toronto to Lisbon discovered a fuel leak in one of the tanks. It took place in the sky over the Atlantic. The commander of the ship, Robert Pish, decided to leave for an alternate airfield located on one of the Azores. However, on the way, both engines caught fire and failed, and there were still about 200 kilometers to the airfield. Rejecting the idea of landing on the water, as giving almost no chance of salvation, Pish decided to make it to land in gliding mode. And he succeeded! The landing turned out to be tough - almost all the pneumatics burst - but the disaster did not happen. Only 11 people received minor injuries.

Domestic pilots, especially those operating Soviet-type airliners (Tu-154, Il-86), often complete the alignment with the holding procedure, that is, for some time they continue flying over the runway at a height of about a meter, achieving a soft touch. Of course, passengers like holding landings more, and many pilots, especially those with extensive experience in domestic aviation, consider this style to be a sign of high skill.

However, today's global trends in aircraft design and piloting prefer landing with an overload of 1.4-1.5 g. Firstly, such landings are safer, since holding landings contain the risk of rolling out of the runway. In this case, the use of reverse is almost inevitable, which creates additional noise and increases fuel consumption. Secondly, the very design of modern passenger aircraft provides for a touchdown with increased G-force, since the operation of automation, for example, the activation of spoilers and wheel brakes, depends on a certain value of the physical impact on the landing gear (compression). This is not required in older types of aircraft, since the spoilers are switched on there automatically after turning on the reverse. And the reverse is turned on by the crew.

There is another reason for the difference in landing style, say, on the Tu-154 and A 320, which are close in class. Runways in the USSR were often notable for low cargo density, and therefore in Soviet aviation they tried to avoid too much pressure on the surface. The Tu-154 rear pillar bogies have six wheels each - this design contributed to the distribution of the weight of the machine over a large area during landing. But the A 320 has only two wheels on the racks, and it was originally designed for landing with more overload on stronger lanes.

Isle of Saint Martin Caribbean, divided between France and the Netherlands, gained fame not so much because of its hotels and beaches, but thanks to the landings of civilian liners. Heavy wide-body aircraft such as the Boeing 747 or A-340 fly to this tropical paradise from all over the world. Such cars need a long run after landing, but at Princess Juliana airport the runway is too short - only 2130 meters - its end is separated from the sea only by a narrow strip of land with a beach. To avoid rolling out, Airbus pilots aim at the very end of the strip, flying 10-20 meters above the heads of vacationers on the beach. This is how the trajectory of the glide path is laid. Photos and videos with landings on about. Saint-Martin has long bypassed the Internet, and many at first did not believe in the authenticity of these filming.

Trouble on the ground

And yet, really hard landings, as well as other troubles, happen on the final leg of the flight. As a rule, not one, but several factors lead to accidents, including piloting errors, equipment failure, and, of course, the elements.

A great danger is the so-called wind shear, that is, a sharp change in wind strength with height, especially when it occurs within 100 m above the ground. Suppose an aircraft is approaching the runway at an IAS of 250 km/h with zero wind. But, having descended a little lower, the plane suddenly encounters a tailwind with a speed of 50 km / h. The pressure of the incoming air will drop, and the speed of the aircraft will be 200 km/h. The lifting force will also drop sharply, but the vertical speed will increase. To compensate for the loss of lift, the crew will need to add engine power and increase speed. However, the aircraft has a huge inertial mass, and it simply will not have time to instantly gain sufficient speed. If there is no headroom, a hard landing cannot be avoided. If the liner encounters a sharp gust of headwind, the lift force, on the contrary, will increase, and then there will be a danger of a late landing and rolling out of the runway. Landing on a wet and icy strip also leads to rollouts.

Man and machine

Approach types fall into two categories, visual and instrumental.
The condition for a visual approach, as with an instrument approach, is the height of the base of the clouds and the visual range on the runway. The crew follows the approach pattern, focusing on the landscape and ground objects, or independently choosing the approach trajectory within the allocated visual maneuvering zone (it is set as a half circle centered at the end of the runway). Visual landings allow you to save fuel by choosing the shortest approach path at the moment.
The second category of landings is instrumental (Instrumental Landing System, ILS). They, in turn, are divided into accurate and inaccurate. Precise landings are made using a course-glide path, or radio beacon, system, with the help of course and glide path beacons. The beacons form two flat radio beams - one horizontal, depicting the glide path, the other vertical, indicating the course to the runway. Depending on the equipment of the aircraft, the course-glide path system allows for automatic landing (the autopilot itself steers the aircraft along the glide path, receiving a signal from radio beacons), director landing (on the command device, two director bars show the positions of the glide path and heading; the task of the pilot, operating the helm, is to place them accurately in the center of the command device) or beacon approach (the crossed arrows on the command device depict the course and glide path, and the circle shows the position of the aircraft relative to the required course; the task is to combine the circle with the center of the crosshairs). Inaccurate landings are performed in the absence of a course-glide path system. The line of approach to the end of the runway is set by radio engineering means - for example, installed at a certain distance from the end of the far and near driving radio stations with markers (LBM - 4 km, BBM - 1 km). Receiving signals from the "drives", the magnetic compass in the cockpit shows whether the plane is to the right or left of the runway. At airports equipped with a course-glide path system, a significant part of landings are made on instruments in automatic mode. The ICFO international organization has approved a list of three categories of automatic landing, and category III has three subcategories - A, B, C. For each type and category of landing, there are two defining parameters - the horizontal visibility distance and the height of vertical visibility, it is also the decision height. In general, the principle is as follows: the more automation is involved in the landing and the less the “human factor” is involved, the lower the values of these parameters.

Another scourge of aviation is side wind. When the aircraft flies with a drift angle when approaching the end of the runway, the pilot often has a desire to “tuck” the steering wheel, to put the aircraft on the exact course. When turning, a roll occurs, and the aircraft exposes a large area to the wind. The liner blows even further to the side, and in this case the go-around becomes the only correct decision.

In a crosswind, the crew often tries not to lose control of the direction, but eventually loses control of the height. This was one of the reasons for the Tu-134 crash in Samara on March 17, 2007. The combination of the "human factor" with bad weather cost the lives of six people.

Sometimes a hard landing with catastrophic consequences results from incorrect vertical maneuvering on the final leg of the flight. Sometimes the plane does not have time to descend to the required height and is above the glide path. The pilot begins to "give the helm", trying to enter the trajectory of the glide path. In this case, the vertical speed sharply increases. However, with an increased vertical speed, a greater height is also required, at which alignment must be started before touching, and this dependence is quadratic. The pilot, on the other hand, proceeds to equalize at a psychologically familiar height. As a result, the aircraft touches the ground with a huge overload and crashes. History of such cases civil aviation knows a lot.

Airliners of the latest generations can be called flying robots. Today, 20-30 seconds after takeoff, the crew can, in principle, turn on the autopilot and then the car will do everything itself. Unless there are extraordinary circumstances, if an accurate flight plan is entered into the on-board computer database, including the approach path, if the arrival airport has the appropriate modern equipment, the liner will be able to fly and land without human intervention. Unfortunately, in reality, even the most advanced technology sometimes fails, aircraft of outdated designs are still in operation, and the equipment of Russian airports continues to be desired. That is why, rising into the sky, and then descending to the ground, we still largely depend on the skill of those who work in the cockpit.

We would like to thank the representatives of S7 Airlines for their help: Pilot Instructor Il-86, Chief of Flight Operations Staff Igor Bocharov, Chief Navigator Vyacheslav Fedenko, Pilot Instructor of the Flight Standards Department Directorate Igor Kulik

Aircraft landing and takeoff speed are parameters calculated individually for each airliner. There is no standard value that all pilots must adhere to, because aircraft have different weights, dimensions, and aerodynamic characteristics. However, the value of speed at is important, and non-compliance with the speed limit can turn into a tragedy for the crew and passengers.

How is the takeoff?

The aerodynamics of any airliner is provided by the configuration of the wing or wings. This configuration is the same for almost all aircraft except for small details. The lower part of the wing is always flat, the upper one is convex. Moreover, it does not depend on it.

The air that passes under the wing when accelerating does not change its properties. However, the air, which at the same time passes through the top of the wing, narrows. Consequently, less air flows through the top. This results in a pressure difference under and over the wings of the aircraft. As a result, the pressure above the wing decreases, and under the wing it increases. And it is precisely due to the pressure difference that a lifting force is formed that pushes the wing up, and together with the wing, the aircraft itself. At the moment when the lifting force exceeds the weight of the liner, the aircraft lifts off the ground. This happens with an increase in the speed of the liner (with an increase in speed, the lifting force also increases). The pilot also has the ability to control the flaps on the wing. If the flaps are lowered, the lift under the wing changes vector, and the aircraft rapidly gains altitude.

It is interesting that a smooth horizontal flight of the liner will be ensured if the lifting force is equal to the weight of the aircraft.

So, the lift determines at what speed the plane will take off the ground and start flying. The weight of the liner, its aerodynamic characteristics, and the thrust force of the engines also play a role.

during takeoff and landing

In order for a passenger plane to take off, the pilot needs to develop a speed that will provide the required lift. The higher the acceleration speed, the higher the lifting force will be. Consequently, at a high acceleration speed, the aircraft will take off faster than if it were moving at a low speed. However, the specific speed value is calculated for each liner individually, taking into account its actual weight, loading degree, weather conditions, runway length, etc.

Generally speaking, the famous Boeing 737 passenger airliner takes off from the ground when its speed rises to 220 km/h. Another well-known and huge "Boeing-747" with a lot of weight off the ground at a speed of 270 kilometers per hour. But the smaller Yak-40 liner is capable of taking off at a speed of 180 kilometers per hour due to its low weight.

Takeoff types

There are various factors that determine the take-off speed of an airliner:

Weather conditions (wind speed and direction, rain, snow).
Runway length.
Strip cover.

Depending on the conditions, takeoff can be carried out in different ways:

Classic speed dial.
From the brakes.
Takeoff with the help of special means.
Vertical climb.

The first method (classic) is used most often. When the runway is long enough, the aircraft can confidently gain the required speed necessary to provide high lift. However, in the case when the runway length is limited, the aircraft may not have enough distance to reach the required speed. Therefore, it stands for some time on the brakes, and the engines gradually gain traction. When the thrust becomes strong, the brakes are released and the aircraft abruptly takes off, quickly picking up speed. Thus, it is possible to shorten the take-off path of the liner.

There is no need to talk about vertical takeoff. It is possible in the presence of special engines. And takeoff with the help of special means is practiced on military aircraft carriers.

What is the landing speed of the aircraft?

The liner does not land on the runway immediately. First of all, there is a decrease in the speed of the liner, a decrease in altitude. First, the aircraft touches the runway with the landing gear wheels, then it moves at high speed already on the ground, and only then does it slow down. The moment of contact with the GDP is almost always accompanied by shaking in the cabin, which can cause anxiety among passengers. But there is nothing wrong with that.

Aircraft landing speeds are practically only slightly slower than takeoff speeds. A large Boeing 747, when approaching the runway, has an average speed of 260 kilometers per hour. This speed should be at the liner in the air. But, again, the specific speed value is calculated individually for all liners, taking into account their weight, workload, weather conditions. If the aircraft is very large and heavy, then the landing speed should be higher, because during landing it is also necessary to "keep" the required lift. Already after contact with the runway and when moving on the ground, the pilot can slow down by means of the landing gear and flaps on the wings of the aircraft.

Airspeed

The speed during landing of an aircraft and during takeoff is very different from the speed at which an aircraft is moving at an altitude of 10 km. Most often, aircraft fly at a speed that is 80% of the maximum. So the maximum speed of the popular Airbus A380 is 1020 km/h. In fact, flying at cruising speed is 850-900 km/h. The popular "Boeing 747" can fly at a speed of 988 km / h, but in fact its speed is also 850-900 km / h. As you can see, the flight speed is fundamentally different from the speed when the aircraft is landing.

Note that today the Boeing company is developing a liner that will be able to gain flight speed at high altitudes up to 5000 kilometers per hour.

Finally

Of course, the landing speed of an aircraft is an extremely important parameter, which is calculated strictly for each airliner. But it is impossible to name a specific value at which all planes take off. Even identical models (for example, Boeing 747s) will take off and land at different speeds due to various circumstances: workload, amount of fuel filled, runway length, runway coverage, presence or absence of wind, etc.

Now you know what is the speed of the aircraft when landing and when it takes off. Everyone knows the averages.

The plane picks up speed gradually. The take-off phase lasts a long period of time and begins with the process of movement on the runway. There are several types of takeoff and speed gain.

How is the takeoff

The aerodynamics of an airliner is provided by a special wing configuration, which is almost the same for all aircraft. The lower part of the wing profile is always flat, while the upper part is convex, regardless of the type of aircraft.

The air passing under the wing does not change its properties. At the same time, the air flow passing through the convex upper part of the wing narrows. Thus, less air passes through the top of the wing. Therefore, in order for the same air flow to pass per unit of time, it is necessary to increase the speed of its movement.

As a result, there is a difference in air pressure in the lower and upper parts of the wing of an airliner. This is explained by Bernoulli's law: an increase in the speed of air flow leads to a decrease in its pressure.

Lift is generated from the difference in pressure. Its action seems to push the wing up, and with it the entire aircraft. The aircraft lifts off the ground at the point in time when the lift force exceeds the weight of the airliner. This is achieved by accelerating (increasing the speed of the aircraft leads to an increase in lift).

Interesting. Level flight is achieved when the lift force is equal to the weight of the airliner.

Thus, at what speed the aircraft will take off from the ground depends on the lift force, the value of which is determined primarily by the mass of the airliner. The thrust force of an aircraft engine provides the speed required to increase lift and take off an airliner.

A helicopter flies according to the same principle of aerodynamics. Outwardly, it seems that the propeller of a helicopter and the wing of an aircraft have little in common, however, each propeller blade has the same configuration, providing a difference in airflow pressure.

takeoff speed

In order for a passenger aircraft to take off from the ground, it is necessary to develop a take-off speed that can provide an increase in lift. The greater the weight of an airliner, the greater the acceleration required for the aircraft to take off. What is the speed of the aircraft during takeoff - it depends on the weight of the aircraft.

So, the Boeing 737 will take off the ground only at the moment when the speed on the runway reaches 220 km/h.

The 747th Boeing model has a large mass, which means that it is necessary to develop a high speed for takeoff. The speed of the aircraft of this model during takeoff is 270 km / h.

Planes of the Yak 40 model accelerate to 180 km/h to break away from the runway. This is due to the lower weight of the aircraft compared to the Boeing 737 and 747.

Takeoff types

Several factors influence the takeoff of an aircraft:

weather;
runway length (runway);
runway coverage.

The weather conditions that are taken into account during takeoff of the aircraft include wind speed and direction, air humidity and the presence of precipitation.

In total, there are 4 types of takeoff:

with brakes;
classic set of speed;
takeoff with the help of additional means;
vertical climb.

The first overclocking option involves achieving the required traction mode. To this end, the airliner stands on the brakes while the engines are running, and is released only when the required mode is reached. This take-off method is used in case of insufficient length of the runway.

The classic takeoff method involves a gradual increase in thrust as the aircraft moves along the runway.

Classic runway takeoff

Auxiliary means are special springboards. Ski-jump take-off is practiced on military aircraft taking off from an aircraft carrier. The use of a springboard helps to compensate for the lack of sufficient runway length.

Vertical takeoff is carried out only with special engines. Thanks to vertical thrust, takeoff is similar to that of a helicopter. Having taken off the ground, such an aircraft smoothly turns into horizontal flight. A striking example of vertical takeoff aircraft is the Yak-38.

Boeing 737 takeoff

To understand exactly how an airplane takes off and picks up speed, consider a specific example. For all passenger jet aircraft, the take-off and climb pattern is the same. The difference lies only in reaching the required speed of the take-off aircraft, which is determined by the weight of the airliner.

Before the aircraft starts to move, it is necessary that the engine reaches the required operating mode. For a Boeing 737, this value is 800 rpm. When this mark is reached, the pilot releases the brake. The aircraft takes a takeoff run on three wheels, the control stick is in the neutral position.

To get off the ground, the aircraft of this model must first pick up a speed of 180 km / h. At this speed, it is possible to raise the nose of the aircraft, then the aircraft accelerates on two wheels. To do this, the pilot smoothly lowers the control down, as a result, the flaps are deflected, and the bow rises up. In this position, the aircraft continues to accelerate, moving along the runway. The airliner will lift off the ground when the acceleration reaches 220 km / h.

It should be understood that this is an average speed value. With a headwind, the speed is less, as the wind makes it easier for the airliner to take off from the ground, further increasing lift.

Acceleration of the aircraft becomes more difficult with high humidity and the presence of precipitation. In this case, the takeoff speed must be faster for the aircraft to take off.

Important! The decision on what speed can be considered sufficient for climbing is made by the pilot, having assessed the weather conditions and the features of the runway.

Airspeed

The flight speed of the aircraft depends on the model and design features. Usually the maximum possible speed is indicated, but in practice such indicators are rarely achieved and aircraft fly at cruising speed, which, as a rule, is about 80% of the maximum value.

For example, speed passenger aircraft Airbus A380 is 1020 km / h, this value is indicated in the technical characteristics of the aircraft and is the maximum possible flight speed. The flight is carried out at cruising speed, which for this aircraft model is about 900 km / h.

Boeing 747 is designed to fly at a speed of 988 km / h, but flights are made at cruising speed, which varies between 890-910 km / h.

Interesting. Boeing is developing the world's fastest passenger airliner, with a top speed of 5,000 km/h.

How does the plane land

The most crucial moments during the flight are the takeoff and landing of the airliner. Movement in the sky is usually provided by the autopilot, while landing and takeoff are handled by the pilots.

Landing is what most excites passengers, as this process is accompanied by a frightening sensation during a decrease in altitude, and then a jolt as the airliner lands on the runway.

Often, when asking how the flight went, you can get the answer that the landing was soft. It is a soft landing that is considered an indicator of the skill of the pilot.

Landing preparations begin in the air, at a height of 25 m above the threshold of the runway for large aircraft, and 9 m for small aircraft. Until the moment when the aircraft is landing, the vertical rate of descent and the lifting speed of the wing are reduced. Decreasing speed causes a reduction in lift, allowing the aircraft to land.

Planes land on the runway immediately. When landing, first contact with the runway occurs, and the aircraft lands on the landing gear. The airliner then continues down the runway on wheels, gradually decelerating. It is the moment of contact with the runway that is accompanied by shaking in the cabin and causes anxiety among passengers.

As a rule, the landing speed is approximately equal to or slightly different from the takeoff speed. So, the Boeing 747 will be able to land at a speed of about 260 km / h.

Video

When the plane lands, all decisions about the need to reduce speed are made by the pilot. Thus, a soft landing characterizes the professional skills of the pilot. However, it should be remembered that the features of the landing of an airliner also depend on a number of climatic factors and runway features.

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