home Visa Have you removed the flaps instead of the landing gear? What happened a minute before the disaster. “They gave takeoff mode, but forgot to remove the flaps

Have you removed the flaps instead of the landing gear? What happened a minute before the disaster. “They gave takeoff mode, but forgot to remove the flaps

On Tuesday, the main “black box” of the Tu-154 that crashed in Sochi was delivered to Moscow. The Life publication published a transcript, the authenticity of which was not officially confirmed, but it followed from it that the crew had problems with the flaps. And an Interfax source, in turn, said that the Tu-154 could have crashed due to a “stall” with insufficient wing lift for takeoff.

“According to preliminary data, the flaps on board operated inconsistently, as a result of their failure to release, the lifting force was lost, the speed was not sufficient to gain altitude, and the plane crashed,” said a source in operational headquarters for work at the scene of the incident.

Novaya Gazeta asked experts to comment on the version with flaps.

Andrey Litvinov

1st class pilot, Aeroflot

— Flaps are very critical. We ( pilots — ed.) at the very beginning they assumed that these were flaps - as soon as it became clear that it was not fuel or weather. There were several versions - technical, pilot error. But it can be both. A technical problem resulted in a pilot error.

Flaps are needed only for takeoff and landing - the wing area increases, the lifting force increases, therefore, the plane needs a shorter takeoff distance than without flaps. You take off with the flaps, gain altitude, and the flaps retract. But they may not clean up if something is broken, or they may not clean up synchronously - one is faster, the other is slower. If they don’t clean up at all, it’s not a big deal; the plane flies on and on. He doesn't go into a dive. The commander simply reports to the ground that he has such a technical problem, returns to the airfield and lands - with the flaps extended, as required during a normal landing. And engineers are already figuring out what the problem is.

But if they are removed asynchronously, then the plane crashes, that’s what’s scary. On one plane of the wing the lift force becomes greater than on the second, and the plane begins to roll and, as a result, falls on its side. If the plane falls over, dives, and begins to lower its nose, the crew instinctively begins to pull the yoke towards themselves and increase the engine speed - this is absolutely normal. But the pilot must control the spatial position of the aircraft.
There is a concept - supercritical angle of attack. This is the angle at which air begins to escape from the wing. The wing becomes at a certain angle, its upper part is not flown around by air, and the plane begins to fall, because nothing is holding it in the air.

I flew the TU-154 for 8 years. I had no problems with the flaps, there were minor failures, nothing serious. It was a good reliable plane in its time. But that was 25 years ago. It is a product of its time. Aeroflot has all new planes - we fly Airbuses and Boeings. And the Ministry of Defense flies the TU-154. Yes, you need to make your own planes, yes, but at least let them take a superjet. On modern aircraft It costs a lot of protection systems, it is actually a flying computer. If some situation happens, the automation prevents the plane from stalling and is very helpful to the pilot. These same planes are all in manual mode, all in manual control. But this does not mean that it should fall, it must be technically sound. It must undergo maintenance. The question for the technicians is why such a serious breakdown occurred on this plane. Anyone can make a mistake. The crew does have experience, but military pilots generally don’t fly much. A military pilot flies 150 hours a year. And civilian - 90 hours per month.

Surprise could also have worked, they did not expect such a development of events, they did not have enough reaction to cope. This does not mean that they are inexperienced. Don't forget that the time was 5 am. Just sleep, the body is relaxed, the reaction is initially inhibited. We have been saying for a long time that we should ban night flights or reduce them to a minimum, we should strive to fly during the day, this is what many European companies do.

You also need to remember that the plane was heavy; the fuel tanks, cargo, and passengers were full. There was little time to make a decision. They didn't have time. This situation, of course, must be worked out. I don’t know how the army trains pilots, but here at Aeroflot it’s being worked out. There is an algorithm of actions for every emergency situation. Everything is endlessly practiced on the simulator. Did this crew go to the simulator when? If you were on the simulator, did you practice specific flap exercises? We are waiting for answers from the investigation.

Source close to the investigation

— Now the entire technical investigation is being conducted by the Ministry of Defense. This is a military aircraft - the Air Force Institute in Lyubertsy is engaged in deciphering the recorders, and all recorders, units, systems were transported to Lyubertsy. Flaps are not a critical situation, but in principle a controlled and manageable situation. There is an algorithm for actions in case of desynchronization or incorrect position of the flaps. Pilots are trained in everything, including in simulators; for every emergency, the flight crew practices how to behave, how to control the aircraft. Each aircraft has its own specifics; algorithms have been developed for the Tu-154. One can assume a combination technical problems and the human factor, but there is still not enough information.

Vadim Lukashevich

Independent aviation expert, Candidate of Technical Sciences

— Failure to retract the flaps is not a disaster. This is a very unpleasant event, but nothing bad should happen from it. And in my opinion, a combination of circumstances and the actions of the crew led to the disaster in the Black Sea.

The essence of airplane flaps is to increase the lift of the wing at low speeds. How a wing works - the higher the speed, the greater the lift. But when the plane takes off, the speed is still low, the same as during landing. And in order to prevent the lift force from decreasing when the speed drops, the flaps in question are extended. You also need to understand that during takeoff the flaps do not extend as much as during landing. When the aircraft is taxiing on the runway, the flaps are already extended, and at the moment of takeoff, the landing gear is sequentially retracted, braking the aircraft, and after 15-20 seconds the flaps are also retracted, hindering the plane as its speed increases. In addition to lifting force, they also create additional air resistance and an additional diving moment - when the plane “wants” to lower its nose.

What happened at the time of the disaster? A heavy, loaded plane, filled with fuel, takes off, the pilots retract the flaps, but for some reason this does not work. In theory, you can continue the flight normally and in this state, without picking up speed, you can turn around and land to fix the problem. It is possible to land with the flaps in this position, but the landing speed will be higher and it will not be very easy. But obviously there was no such solution here. Perhaps the problem with the flaps was not noticed immediately, and when the plane began to lower its nose, words deciphered from the recorder may have been spoken.

Among some of the media and bloggers, the main version of the Tu-154 RA-85572 crash near Sochi was the version of the erroneous retraction of the flaps instead of the landing gear. It just so happens that journalists grab simple versions - so that everything is explained as simply and immediately as possible. Moreover, this version even eclipsed the first such simple version circulating on the Internet - a very rear alignment - which “led to excessive nose lift and, as a result, stalling after takeoff.” The version of the flaps states that “as a result of their erroneous retraction instead of the landing gear, an emergency situation arose in the last 10 seconds, which the crew was unable to correct due to the low altitude.” It is this version that I will consider in this post.

But first, let's look at what flaps are. Flaps, as the name suggests, are “behind the wing” - a deflectable surface located on the trailing edge of the wing.

Flaps increase the curvature of the wing, thereby creating greater lift and are used in takeoff and landing modes, providing lower speeds and smaller run/run distances.
However, this does not come for free - the extended flap increases aerodynamic drag - i.e. More engine thrust will be required. And the second effect is that it creates a dive moment. This picture will clearly explain this:

When the flaps are extended, the point of application of lift shifts - from green (for a clean wing) to yellow (with flaps extended). This leads to the appearance of a diving moment (i.e., forcing the nose down) - orange arrow. To compensate for this moment, you need to either use the elevator or shift the stabilizer to create the opposite - a pitching (i.e., raising the nose) moment - blue arrow. Why elevator or stabilizer? But because the center of gravity of the aircraft - i.e. the beginning of the arrow G – may change depending on the load. And the leverage of the force and, consequently, the magnitude of the moment depend on this. For the Tu-154 there are three main alignment ranges - front, middle and rear.

In the case of front alignment, the shoulder is largest, in the case of rear alignment, it is the smallest. Formally, it is possible to use the elevator to compensate for the diving moment, but then at different alignments it will have to be deflected to different angles, which is inconvenient for piloting and which reduces its power reserve for pitching up. Therefore, compensation for the diving moment in this case is carried out by rearranging the stabilizer to ensure uniform control of the aircraft. In the case of rear alignment, the stabilizer for the take-off position of the flaps (28 degrees) is not adjusted, for the middle one it is adjusted by 1.5 degrees to pitch up, and for the front - by 3 degrees to pitch up. When extending/retracting the flaps, the stabilizer adjustment is usually done automatically and synchronously to ensure smooth piloting. However, even for rear alignment, the elevator must be deflected for pitching to compensate for the diving moment. In order not to get tired, in this case a trimmer or trimmer effect is used - removing the force from the handle - then the steering wheel, and as a result - the elevator - remain in a deflected position, but you no longer need to make an effort to keep them in this position. The same method can be used to balance the aircraft in other modes - for example, when climbing - when the rudder needs to be deflected more.
When the flaps are retracted, all the effects described above for a balanced aircraft work in the opposite direction:

1) lifting force decreases
2) air resistance decreases
3) there is a moment to pitch up (the plane begins to lift its nose)

And such effects, when they occur due to pilot error, are really undesirable during takeoff, since they can lead, say, to a loss of altitude or loss of speed and, as a result, a crash of the aircraft. However, these three effects occur simultaneously and in some places can even compensate for each other, for example, a decrease in aerodynamic drag helps accelerate the aircraft, and an increase in pitch (lifting the nose) leads to an increase in lift. The qualitative model described above does not describe these subtleties in any way, therefore, in order to look at the behavior of a particular aircraft, taking into account the mutual influence of these effects, there are three options:

Simulate a similar flight on a laboratory aircraft by test pilots (of course, they will not reproduce this mode near the ground, but will simulate it at a safe altitude).

Perform full-scale modeling - say, take a model and reproduce the conditions in a wind tunnel.

Perform mathematical modeling on a computer.

And the last option is quite accessible to almost anyone - just take a simulator with a model of exactly the same aircraft.
It was the latter option that I did, taking the free FlightGear simulator with a Tu-154B model from the Tupolev Project installed on it, which volunteers converted from the original model for Microsoft Flight Simulator. FlightGear can use several flight dynamics modules, but Tu uses JSBSim, a six-degree-of-freedom module written by a former NASA engineer and widely used by universities to simulate flight and debug autopilot algorithms. It has been distributed, including in source code, since the late 90s and is therefore well debugged. Another advantage of JSBSim is that it allows logging of almost all parameters used in calculations - i.e. for example, I can record the dynamics of changes in lift force or longitudinal moment, as well as parameters of some systems and a specific model - for example, the AUASP activation flag (alarm about exceeding the angle of attack for the Tu-154). This allows me to build graphs after the flight and see the dynamics of change.
For test flights, in order not to mess with the stabilizer, I took the rear centering, but the most forward among the rear ones - 32% MAC - in order to have a larger shoulder. I also set the weight to the maximum - 98 tons, in order to see the behavior of a heavy aircraft. Since the default installation in the simulator does not include Sochi airport, I did not bother with its installation, but carried out all the experiments at the San Francisco airport since there are also long runways there, especially in terms of parameters such as altitude/speed/distance this is completely unprincipled. To qualitatively examine the behavior and simplify piloting, the flights were carried out during the day in calm weather - anyway, after takeoff, piloting is carried out using instruments.
And first, let's look at how an airplane behaves when it is balanced in the climb mode for a speed of approximately 320 km/h after the flaps are retracted, if it is not controlled in pitch.

And it will be like this:

The flight was carried out like this: after takeoff and balancing at the required speed, I simply retracted the flaps without touching the landing gear and pitch controls. After retracting the flaps, the plane began to lift its nose. Since the resistance force had also decreased, he nevertheless accelerated. By increasing the pitch, it compensated for the loss of lift and did not sag in altitude, but rather began to gain it. Subsequently, an increase in pitch led to a decrease in indicated speed, but due to inertia it still gained altitude. Having gained about 663 meters at the maximum point, it began to fall from there without an indicated speed - it dropped to zero. And after somersaulting and lowering his nose, he fell to the ground in a tailspin. The entire flight continued from the start point of the takeoff run (the engines were brought to takeoff mode) to the crash site - about 110 seconds. The distance between the crash point and the take-off point is approximately 7600 meters.

The first intermediate conclusions can be drawn from this flight:
- approximately 40 seconds are spent on the run, which is 2000-2100 meters
- after 70 seconds of flight, if we assume that they are calculated after setting the stopwatch before takeoff, the plane was still in the air. Consequently, 70 seconds - and they are declared by the Ministry of Defense - must be counted as a minimum from the point of separation - i.e. the time the plane was in the air.

It would seem that the point of impact is somewhat similar - which means the version about the flaps is correct!
However, neither the point of impact, nor the maximum altitude gained, nor the speed during the collision correspond to the MO data. And most importantly, I didn’t fly the plane, and that’s not how it’s done.
Therefore, we need to dig further. And here, for starters, it’s worth considering how the Tu-154B takes off and how it is controlled during takeoff.
To do this, consider the takeoff technique:

After the engines are switched to takeoff mode, the plane begins its takeoff run.
When liftoff speed (VR) is reached, the control wheel is vigorously taken over and the nose gear is raised until the aircraft lifts off the runway. At the first stage, the aircraft is accelerated so that the speed reaches V2 at an altitude of 10.7 meters and the landing gear is retracted at an altitude of 5-10 meters. In the second stage, the aircraft is further accelerated to reach a speed of V2 + 40 km/h. At the third stage, at a speed of V2+40, an altitude climb of 120 meters is performed while maintaining this speed. After passing this altitude, the steering wheel is pulled back a little and the plane is accelerated to 330 km/h - the speed at which the flaps begin to retract - after which the flaps are retracted. The flaps can be retracted in two stages - first up to 15 degrees from 28 degrees and after reaching a speed of 350 km/h - final retraction to zero degrees. But for the Tu-154B it is also possible to retract the flaps in one step. At the end of harvesting, the speed should reach 380-400 km/h, and the height should be 400 meters. After retracting the flaps, the aircraft is still accelerated and the engines are switched to nominal mode after reaching an altitude of 450 meters.

Speeds depend on take-off weight - with a weight of 98 tons VR = 260 km/h, and V2 = 280 km/h, i.e. in the third stage you need to maintain a speed of 320 km/h. In addition, this scheme takes into account take-off in a straight line, and when moving according to take-off schemes, the cleaning of the mechanization can be postponed - if it is necessary to perform a turn/turn according to the scheme. And at Sochi airport, when following the BINOL 2A scheme, the situation is exactly this:

The first three segments look like this:

First, on the takeoff straight, you need to reach the point in the green circle, gaining a height of 150 meters or higher.
The distance of this point from the start of the takeoff run is approximately 4 kilometers.

Then you need to turn about 30 degrees to the right along the course and follow the point in the purple circle. The distance of this point from the green one is also approximately 4 kilometers.

Then you need to turn left onto course 249 and follow route 23 to the NIDEP point, gaining at least 800 meters of altitude.
The distance between the NIDEP point and the takeoff start point in a straight line is approximately 28 kilometers.

During the first two kilometers of flight, you need to gain 150 meters of altitude. During this time, it is not possible to completely remove the mechanization - either it can not be removed, or the flaps can only be removed to 15 degrees. But on a straight line from the green to the purple point at a speed of about 360 km/h, we get a flight duration of about 40 seconds - during this time you can either retract the flaps to zero, or remove them in one or two steps from 28 degrees takeoff.
To simulate the normal takeoff mode, I went through this section without retracting the flaps and did not make any turns - for a high-quality picture this is not necessary as a first approximation.
But now it’s time to return to retracting the flaps instead of the landing gear.

If you do this from a height of 5-10 meters, then in 2 kilometers the flaps will have time to retract. As was noted when considering a normal takeoff, after the flaps are retracted, the second and third stages will be flown instead of the landing gear. According to the Flight Manual, speed must be maintained in these sections - in particular, 320 km/h at the third stage. However, formally, there is another way - to maintain pitch - for example, this is what the instructor advised me to maintain on the Boeing 737NG full-cabin simulator during takeoff. When climbing in the third stage, the pitch for the Tu-154B will be approximately 9-10 degrees. I will consider these two piloting options:
- fly approximately 3 km after takeoff and retract the flaps to zero, maintaining a speed of 320 km/h.
- fly about 3 km after liftoff and retracting the flaps to zero, maintaining a pitch of 9-10 degrees.

I reduced all the results to two graphs - the dependence of height on distance from the take-off point and the dependence of speed on distance from the take-off point. Moreover, the interval between readings for logging is one second – i.e. By counting the points you can understand the time between them.
Here they are:

So:
at normal takeoff(blue “Normal” curves) I reached the desired speed of 320 km/h (V2+40) at about 30 meters and definitely couldn’t maintain it - it varied from 320 to 329 km/h. Nevertheless, I arrived at the control point of 150 meters on the coast even with a small margin - at an altitude of 155 meters.

at uncontrolled pitch control(purple “Stop” curves) the plane reached the coast maximum speed at 342 km/h - due to the high pitch, he did not have time to accelerate further. At the same time, he gained a height of approximately 100 meters and, by inertia, is still continuing to gain it. However, he doesn’t have long to fly.
But the most interesting thing happens when the flaps are retracted incorrectly and the parameters are maintained.

Maintaining pitch.
If you maintain pitch (red “Pitch” curves), then the plane gains altitude very slowly - no more than 3 m/s and it reaches the coast at an altitude of just over 50 meters. But it picks up speed well, reaching the coast at a speed of more than 370 km/h. Moreover, if you take the pitch less - say 8 degrees, then it will gain even less altitude and it has every opportunity to hit point obstacles after the airfield and crash before approaching the sea - on the coast the altitude will be 30 meters. This behavior could not have gone unnoticed by the navigator, who was pronouncing altitudes and speeds, and he would have noticed it quickly enough - in the first fifteen seconds after takeoff. The Tu-154B aircraft itself does not produce any signals in this case - the angle of attack does not go beyond 12 degrees, but if it were equipped with an early warning system for approaching the ground (TAWS), then the third take-off mode with the signal " Don't go down" (DON'T SINK). Having a reserve of speed, when retracting the landing gear (this is about five seconds), the plane could be returned to a stable climb - and this would not have happened at all in the last 10 seconds of the flight of that flight.

Maintaining speed.
If you maintain speed (green “Speed” curves), then the plane, on the contrary, gains altitude. Moreover, towards the coast it gains as much as 180 meters. But here another effect occurs - after approximately retracting the flaps to 15 degrees, the AUASP display will light up and a sound signal will appear. Moreover, from this moment they will signal continuously - all ten seconds of travel to the coast point. And it’s clear why - because maintaining a speed of 317-325 km/h is not enough on a clean wing - you have to go at increased angles of attack. And although there is a margin compared to the stall speed of 295 km/h (for a weight of 98 tons on a clean wing), it is less than the required 15%.
In this case, having a headroom, it was also possible to remove the landing gear and reach a safe mode by a slight descent. According to the BINOL 2A diagram, there was no need to gain even more altitude - on the contrary, there was a solid margin for gaining 800 meters required after 28 kilometers of flight. In addition, in order to maintain the aircraft in this mode, it is necessary to maintain a pitch of about 20-23 degrees! The angle of attack in this case reaches 14-15 degrees (the red part of the scale on the UAP-12 indicator), which, however, is less than the critical value of 21 degrees for a clean wing along the polars.

Conclusion.
Considering the dynamics of the behavior of the aircraft in the model case of erroneously retracting the flaps instead of the landing gear for a given departure pattern, one can, without any doubt, assert that the hypothesis that the crew retracted the flaps instead of the landing gear I found out about this in the last 10 seconds of the flight, no longer being able to influence the catastrophe - obviously false– the crew was aware of this after the first 10-15 seconds of the flight.

P.S. A little later, in a separate post, I will describe how to install the Tu-154B model, configure and obtain parameters, so that anyone can reproduce my tests and either confirm, refute, or adjust the data and results I received.

It consists of a whole set of movable elements that allow adjustment and control of the flight of the device. The complete set of wing elements consists of flaps, spoilers, slats, spoilers and flaperons.

Flaps are profiled deflectable surfaces that are located symmetrically to the trailing edge of each wing. When retracted, they act as an extension of the wing. When released, they move away from the main part of the wing to form a gap.

They significantly improve the load-bearing characteristics of the wing when lifting off from the runway, as well as when the airliner is climbing and landing. They provide excellent lift and control of the vehicle at fairly low flight speeds. Throughout the history of aircraft manufacturing, many models and modifications of this part have been developed and implemented.

Flaps are an integral part of the wing. When they are released, the curvature of the wing profile increases significantly. Accordingly, the load-bearing capacity of the aircraft's wings increases. This ability allows aircraft to move at low speeds without stalling. The operation of the flaps allows you to significantly reduce the speed of landing and takeoff without danger to the aircraft.

Due to the extension of the flaps, aerodynamic drag increases. This is very convenient when landing, as they create more drag, which allows you to reduce your flight speed. During takeoff, such drag is a little inappropriate and takes away some of the engines' thrust. Accordingly, when landing, the flaps are fully extended, and during takeoff, at a small angle, in order to facilitate the operation of the power plant.

Due to the additional longitudinal moment of flight, overbalance occurs. This, of course, complicates the work of pilots in controlling and maintaining the normal attitude of the aircraft. In modern aviation, most aircraft are equipped with slotted flaps, which can consist of several sections; accordingly, they form several slits. The presence of gaps between the flap sections allows high-pressure air on top of the wing to flow into the low-pressure area below the wing.

The structure of the flaps ensures that the air stream flows tangentially relative to the top of the surface. The cross-section of the slot narrows towards the edges, this allows the flow rate to increase. Having passed the flap slots, the jet with high energy levels interacts with the layer of air under the wing, thereby eliminating the occurrence of turbulence. The flaps can be operated at the pilot's command or in automatic mode. Cleaning and extension of elements occurs due to electric, pneumatic or hydraulic drives. The first aircraft in our country on which flaps were installed was manufactured back in the 20s of the last century; it was an R-5 type aircraft. These wing elements began to be used more widely in the 30s, namely with the advent of machines with a monoplane body.

Main types of flaps

Rotary or simple flap. The most elementary in its design, it allows you to increase the lifting force of the vehicle by changing the curvature of the wing profile. This design allows you to increase air pressure from below the wing. Of course, this type is significantly inferior in efficiency to the panel type.

Shield type flaps. They can be retractable or simple. As for simple flaps, they are represented by a controllable surface that is in the retracted position, while they fit tightly to the bottom of the wing. By deviating, they create a rarefied pressure zone on top of the wing. Accordingly, the upper boundary layer flows down. Pressure increases from below, which creates additional lift. All this contributes to lift-off and climb at much lower speeds. Speaking about retractable shield flaps, it is worth noting that, in addition to deflection, they have the ability to extend backwards. This in turn increases their efficiency. This design allows you to increase lifting force by 60%. They are still used today on light aircraft.

Slotted flap type. They get their name due to the formation of a gap when they are deflected. A flow of air passes through it, which is directed with great force into the low pressure zone formed under the wing of the aircraft. At the same time, the flow direction is well thought out and does not allow flow disruption. The gap formed by the flap narrows towards the edge, which allows the passing flow to receive maximum energy. On modern aircraft, slotted flaps are installed, consisting of several sections, which can form from one to three slits. Using such flaps, the aircraft gains lift up to 90%.

The Flaurea flap has a retractable design. The difference is the ability to extend not only backwards, but also downwards. This significantly increases the overall curvature of the aircraft's wing profile. This extension can create up to three slits. The increase in lifting force reaches 100%.

Junkers flap. It is made like a slotted flap, only its upper part serves as an aileron. This allows for better control of the aircraft's roll. The inner two parts of the structure perform the work of the flap. This design was used in the Ju 87 attack aircraft.

Jungmann design flap. This design was first installed on a British-made carrier-based fighter such as the Firefly. By increasing the wing area and lifting force, they were planned to be used at all stages of the flight.

Goudge flap. The main objective of the design was to reduce speed during landing. In addition to changing the curvature, they also increased the area of the wing itself. This design made it possible to reduce the takeoff speed during takeoff. The inventor of this scheme is the English designer A. Goudge, who worked hard on aerodynamic schemes. They were equipped with the Short Stirling aircraft in 1936.

Blow-type flap. This design had a high-quality control system for the upper boundary layer. Blowing made it possible to significantly improve the characteristics of the device during landing. This design made it possible to ensure a high-quality overall flow around the wings. It is known that the boundary layer arises due to the occurrence of viscous friction of the air flow on the surface of the aircraft, while the flow velocity near the skin is zero. It is through the system of influence on this layer that the flow can be prevented from stalling.

Jet flap. It provides a powerful air flow in the plane of the wing, which flows out from the lower surface. This changes the streamlining and increases the lift of the device. As lifting force increases, more air flow is required. It is worth noting that the effectiveness of this design decreases significantly as the overall wing aspect ratio decreases. Near the ground, such flaps do not justify the designers' calculations. Because of this, they are not widely used in the aircraft industry.

The stationary Gurney flap is represented by a perpendicular plane, which is installed at the end of the wings.

The Coandé flap has a constant surface curvature. It is designed for the so-called Coandé effect - when the jet sticks to the surface of the wing, which is subject to blowing.

Designers around the world are still working fruitfully to improve the aerodynamic properties of aircraft.

“According to preliminary data, the flaps on board operated inconsistently, as a result of their failure to release, the lifting force was lost, the speed was not sufficient to gain altitude, and the plane crashed,” said a source at the operational headquarters for work at the scene.

Novaya Gazeta asked experts to comment on the version with flaps.

Andrey Litvinov

1st class pilot, Aeroflot

I flew the TU-154 for 8 years. I had no problems with the flaps, there were minor failures, nothing serious. It was a good reliable plane in its time. But that was 25 years ago. It is a product of its time. Aeroflot has all new planes - we fly Airbuses and Boeings. And the Ministry of Defense flies the TU-154. Yes, you need to make your own planes, yes, but at least let them take a superjet. Modern aircraft have a lot of protection systems; it is actually a flying computer. If some situation happens, the automation prevents the plane from stalling and is very helpful to the pilot. These same planes are all in manual mode, all in manual control. But this does not mean that it should fall, it must be technically sound. It must undergo maintenance. The question for the technicians is why such a serious breakdown occurred on this plane. Anyone can make a mistake. The crew does have experience, but military pilots generally don’t fly much. A military pilot flies 150 hours a year. And civilian - 90 hours per month.

Source close to the investigation

— Now the entire technical investigation is being conducted by the Ministry of Defense. This is a military aircraft - the Air Force Institute in Lyubertsy is engaged in deciphering the recorders, and all recorders, units, systems were transported to Lyubertsy. Flaps are not a critical situation, but in principle a controlled and manageable situation. There is an algorithm for actions in case of desynchronization or incorrect position of the flaps. Pilots are trained in everything, including in simulators; for every emergency, the flight crew practices how to behave, how to control the aircraft. Each aircraft has its own specifics; algorithms have been developed for the Tu-154. A combination of technical problems and human factors can be assumed, but there is still not enough information.

Vadim Lukashevich

Independent aviation expert, candidate of technical sciences

Aviation specialist, pilot from Sheremetyevo, who asked not to be named:

Every time we step on the same rake. The reason for this is complete lack of professionalism.

Let's take for example dead crew: the commander is retrained from navigators, the co-pilot is from flight engineers. At the same time, the commander has been flying for the first year. That is, his first “minimum”: 80 per 1000 (he is allowed to land at a maximum cloud height of 80 m, visibility of 1000 m - Auto.). Experienced pilots, with the automatic equipment that Boeing has, calmly land even in completely cloudy conditions. Moreover, the weather in Kazan was good, and the commander simply had to sit down.

If the commander has any problems, he always has an assistant on his right. But there sat a man who himself did not have strong manual piloting skills, a pilot of an even lower level - a former flight engineer. So what could have happened to these “professionals” when the commander reported to the dispatcher about the plane’s non-landing position?

The non-landing position is the maximum deviation from the course and glide path that prevents the crew from completing the landing safely. If the crew goes beyond these maximum deviations, they are obliged to go around, which is what they tried to do. And then, as my experience suggests, the situation could develop like this: in order to go around, they gave the takeoff mode, while forgetting to remove the flaps. And in the landing position they were fully extended, and they urgently needed to be removed to the take-off position. If this is not done, the plane instantly goes to high angles of attack and goes into a tailspin.

I immediately had a question: how could the airline management form such a flight crew - from an inexperienced former navigator and an undertrained flight engineer? I opened their website, after which the question disappeared by itself. I read that the head of this airline is Aksan Rimovich Giniyatullin, born in 1977, who graduated from the Tashkent Agricultural Institute, becoming an engineer in irrigation and mechanization. (By the way, information on the general director of the Tatarstan company immediately after the tragedy in Kazan mysteriously disappeared from the airline’s website— Auto.).

Before his appointment as general director of the Tatarstan company, Aksan Giniyatullin worked exclusively as an adviser everywhere. I studied for one and a half to two years to become an accountant in the USA, after which I worked in Canada, where I was involved in promoting foreign technology to Russia. Then he returned to his homeland, his penultimate place of work was the Bars airline, where for a year he spent a year purchasing foreign aircraft for the company.

Therefore, I dare to say that this person hardly understands what an airplane is and how to organize flight safety in an airline. But if you think that Aksan Giniyatullin is an exception, then you are mistaken. Look through the list of heads of other airlines, you will see a similar picture everywhere.

Vladimir Gerasimov - air crash expert, pilot civil aviation, Candidate of Technical Sciences:

It is clear that now we can only make assumptions, and yet... What is an approach? Before entering the glide path - and according to the classic glide path this is 8 km 600 meters from the end of the runway (runway) - the crew releases the wing mechanization, which includes flaps and slats, and rearranges the stabilizer. This is done to reduce landing speed.

Before flying past the long-range radio station - which is 4 km from the runway - he must report that he is ready to land, after which he receives permission to do so and flies silently for the remaining 4 km, landing.

But if the pilot reported to the controller that he was going around due to the non-landing configuration of the aircraft, it is important to know: at what point did he do this? And, accordingly, when I received permission for this care. This is the first thing.

And second: by non-landing configuration, many understand only the position of the aircraft relative to the glide path. Roughly speaking, I missed the runway and went for a second approach. To be precise, the non-landing configuration of an aircraft is also its landing gear position, the position of the slats and flaps. Let’s say they are under-produced in the landing configuration, or, what is much worse, the mechanization is not released synchronously. When the flaps are extended on one wing, but not on the other. In this case, a heeling moment appears towards the unreleased mechanization.

It is still unclear what exactly this crew might have had. According to the rules, the pilot had to explain to the controller the reason for his go-around. But he didn’t do this, so we can assume a lot here: let’s say his stabilizer, or the horizontal tail on his tail, flew off, and the plane immediately “pecked down.”

We are now generally talking about the final stage. But why did he go around the first time? How long did he hang around the airfield? There is not just one reason here, but several. Perhaps something prevented the commander from completing the approach, but at the same time he himself missed something somewhere.

Let's say one flap flew off and it began to heel. But he missed the situation at the beginning, although he should have immediately removed the engine operating mode, since they turn the plane over if the extended flap blows more than necessary. There is still too much that is unclear. Although it is very likely that some kind of technical malfunction resulted in inadequate actions by the crew.