Yuri Sytnik, Honored Pilot of the Russian Federation, member of the Commission under the President of the Russian Federation for the Development of General Aviation, experience of flying the Tu-154 - more than 20 years.
On any aircraft, flaps are used in order to reduce the length of the takeoff run and the mileage of the aircraft during takeoff and landing. The plane takes off at a speed of 700-900 km/h, and comes in for landing at a speed of 280-220 km/h per hour, depending on the type of aircraft. Tu-154 comes in for landing at a speed of 260 km/h, and takes off at a speed of 280 km/h. There is a command "Frontier", "Rise", the aircraft is taking off. In order for the plane to take off at such speeds, you need to change the wing. For this purpose, there are slats and flaps. That is, they move out of the wing, increase its area, change the curvature, thereby increasing lift at a lower speed. And in a horizontal flight, such a swing is not needed, you need to transfer passengers faster, the plane accelerates to a speed of 800-900 km / h, the flaps have already been removed. Everything is compactly pressed into the wing, and it becomes faster. The aircraft continues to fly at that speed. Then, when the plane descends and approaches the airfield area, the flaps are again extended first, then the landing gear. On the Tu-154 flaps are released at 45 degrees.
Before takeoff, the flaps are extended on the runway. The aircraft taxis, flaps are extended for takeoff and set to 28 degrees. Further, the aircraft increases engine operation, starts the takeoff run, lifts off the ground, retracts the landing gear, when it reaches a speed of 340 km / h and an altitude of at least 120 meters, the flaps are retracted. At what stage of the case with this TU-154 are we talking about flaps? Unclear.
And those who write that the flaps were released inconsistently write nonsense. If the flaps are mismatched, there is synchronization when the faulty flap stops and the serviceable one “works under it”. I have other, for example, information, that the speed was 300 km/h, and we are talking not about the flaps, but about the rack (ed. note - the main power element of the aircraft landing gear). Something happened to the stand. Why did she stay on the ground and not in the sea? So he touched the ground after taking off from the runway? Dont clear. But I know that the stand was found on the shore. How did she get there? She is heavy! She weighs over a ton. How could she have been thrown away? What about a storm?
It is not clear what height it was. If this height was 15-20 meters, then it is clear what it is. And if the height was 200 meters, this is a completely different option. We do not yet know the true height, it is impossible to assert anything. If the height is 15-20 meters, then the crew made a mistake, and instead of retracting the landing gear, they retracted the flaps at low speed, at a speed of 300 km/h. In this case, the commander lifts his nose so as not to touch the water, puts the aircraft in the second mode and falls into the water. And if, after a height of 120 meters, the flaps began to retract out of sync, he simply turned over, and he was already in the water. But there is a system that controls this, it cannot be. Then everything would be different, the whole dynamics of the flight would be different, he would not fall, but gain his altitude. And here he is already lying one and a half kilometers from the coast. I don't think the flaps have anything to do with it. I think the crew did the wrong thing. Who was sitting in the right seat - the co-pilot or the checker? This is also a question.
The on-board equipment of the Tu-154 aircraft of the Ministry of Defense of the Russian Federation worked abnormally, this was announced by the Minister of Transport of Russia Maxim Sokolov. According to investigators, the last flight of the aircraft lasted about 70 seconds, during which time the liner rose to a height of 250 meters at a speed of 360-370 kilometers per hour.According to the minister, the first data of examinations may appear in January, the final conclusions about the causes of the disaster will be made after the black boxes are deciphered.According to a preliminary analysis of the data, the cause of development emergency situation on board there was a problem with the flaps.
The main versions of the crash for The Insider were commented by an independent aviation expert, ex-designer of the Sukhoi Design Bureau Vadim Lukashevich.
Version 1: failure of flaps or instruments that determine the speed
Technically, the version with flaps is flawless, unfortunately, such problemsnot very often, but they do happen. VIn this case, most likely there was a non-retraction of the flaps, this is a very unpleasant situation, but not a disaster. And that is why, probably, the pilots did not perceive what was happening as something extraordinary, and did not give an alarm.
Before takeoff, the flaps on the right and left wings are extended, they serve to increase the lift of the wing at low speed. After the aircraft liftoff, the landing gear is first removed, and then, after 15-20 seconds, the wing mechanization, including flaps, begins to be removed. The speed increases, and as it increases, the lift also increases, and the flaps create both drag and a diving moment.
That is, with an increase in speed, if you do not remove the flaps, the plane tries to lower its nose. The following happens: on takeoff, the plane picks up speed, the pilots start to retract the flaps, but for some reason they do not retract. Retraction is synchronized - this is very important, because they must either be retracted or released to some position, but always on the right and left wing, otherwise one wing will have more lift than the other, and the plane will simply tip over.
Suppose there is some kind of malfunction, the flaps do not retract, and this is a completely solvable situation, because in this position you can lock in, not increase speed, and try to turn around, come in for a landing and sit down. The plane also lands with the flaps extended, and they are extended even more to move into the landing position. If the pilots had immediately decided to land, then the flaps could not be removed.
It is obvious that the situation developed very quickly, the crew did not have a margin either in speed or in altitude, and since the aircraft began to lower its nose as the speed increased, the pilots could take the helm, thereby increasing the angle of attack, and go to its supercritical angle and stall. The plane fell down, sank backwards and hit the side of the water.
The fact is that the lifting force of the wing occurs at very small angles of attack - this is the angle between the longitudinal axis of the wing section and the oncoming air flow. The angle is small, a few degrees. Moreover, as this angle increases, the lifting force first grows almost linearly, and after some value, called the critical angle of attack, it practically disappears, falling to zero. That is, the wing ceases to flow around the air as intended, the flow stalls and that's it, the plane fails. They could just jump out at this critical angle of attack. For aircraft of this kind, this is approximately 11, 12, 13 degrees - this should be looked at specifically in the documentation.
The cockpit has a signaling device that warns the pilot about approaching the critical angle of attack and an audible alarm, the aircraft in this situation begins to behave very badly. Shaking begins due to wing stall, and the plane warns that it will be bad further. Perhaps the situation developed quickly, and the pilots automatically instinctively pulled the steering wheel towards themselves so that the nose would not drop.
There is another option - the ground speed is also determined by the pressure of the oncoming air, and if this system was faulty or malfunctioning, then the pilots could, flying on instruments, inadequately perceive the current speed of the aircraft.
The pilots could be sure that the speed of the aircraft was greater than it was, and simply turned up their nose, believing that it was enough.
They could be sure that the speed of the aircraft was greater than it was, and simply turned up the nose, believing that it was enough. But in fact, the speed is small, so this flow arises, and they sink and hit the surface of the water. In this way, either the pilots simply corrected the situation, or they were sure that they had a margin of speed.
Flaps problems happen on this type of aircraft, and in general in aviation. The more properly the aircraft is serviced, the less likely such cases are. TOunfortunately, if this version is correct, then all these people died due to an unfortunate set of circumstances.
That is, at first there was a technical problem, and it was superimposed by the wrong actions of the pilots. V aviation accidents different factors are superimposed on one another, while each of them individually does not lead to a catastrophe. It should not be forgotten here that this was already the second night flight for the pilots: they took off from Chkalovsk, spent two and a half hours in the air, then landed at Adler airport - not the easiest airport, refueled there and flew again.
It is necessary to understand whether the instruments worked correctly or it was purely a mistake of the pilots. It is necessary to check the readings from the parametric recorder, which recorded several dozen flight parameters - how the systems worked and so on. MIt could so happen that there was not enough engine thrust, this is another factor that could overlap. At least the plane took off normally, and there was no information about the failure of the engines. The problem with the flaps, that is, a technical problem, was the trigger for further developments.
Version 2: the crew members mistakenly retracted the flaps, not the landing gear:
So far, we have been talking about one of the possible scenarios - it was a technical reason related to the flaps: they remained in their take-off position, when the aircraft accelerated, a dive moment began to occur, the pilots pulled the helm, reached a critical angle of attack, the aircraft sank and fell.
But the fact is that all our reasoning is based on the decoding of the voice recorder published by the Life channel (and the authenticity of which is not obvious), on the recording the pilots allegedly shouted: “flaps!”, And then there was a sound alarm about exceeding the angle of attack, and the last cry was: "Commander, we are falling."
This cry of "flaps!" (if it took place at all) can be interpreted differently: the pilots made a gross mistake, and together with the landing gear the flaps were removed.
What usually happens: when the plane rolls out, it starts to run along the runway - the flaps are released to the takeoff position. Then the brakes are released, the engines are turned on to maximum thrust, the aircraft takes off, and when a certain speed is reached, the commander decides to take off and takes the helm.
First, the front strut comes off, then the main struts, and the plane comes off the runway. It takes off, and literally immediately, after 3-5 seconds, the landing gear is cleaned. The landing gear must be retracted somewhere after the aircraft reaches a height of 100-120 meters. And then it flies with a climb, and after 30 seconds after taking off from the runway at a height of several hundred meters, the flaps begin to interfere and their cleaning begins.
The sequence of actions of the crew during takeoff is as follows: first, immediately after taking off from the runway, the landing gear is removed, and then, after some time, 20-40 seconds, the wing mechanization begins to be removed and the flaps are removed.
The flaps that we hang behind the wing are removed, and at the same time on the Tu-154 the slats are a small surface on the leading edge. At the same time, the stabilizer, a horizontal small winglet in the very tail at the top of the keel, moves from the takeoff and landing position to the normal one. More important point: landing gear retracts quickly enough, in 3-5 seconds, hydraulic drives, cylinders work, and wing mechanization, including flaps, retracts for a longer time, about 15-20 seconds.
And the problem is that in the cockpit the landing gear and flap retraction handles are not far from each other: landing gear retraction - this handle is located on the top panel above the right pilot, and the flap retraction or flaps handle is also on the top panel, but between the pilots, i.e. on the center console between them. Thus, the second pilot is responsible for the landing gear, and both pilots can reach the flap lever, but with different hands.
Although the levers are close by, they are of different shapes, and in order to retract the landing gear or flaps, you need to move these handles in different ways.
Although the levers are close by, they are of different shapes, and in order to retract the landing gear or flaps, you need to move these handles in different ways. However, they are close to each other, and novice pilots sometimes make mistakes. Experienced pilots, of course, do not make such mistakes, but, as they say, there is a hole in the head of an old woman. This is a gross error, but we cannot rule it out.
If we assume that the crew, the co-pilot, or one of them mistakenly removed the flaps instead of the landing gear, then theoretically the picture is similar to what happened later: the plane accelerates, leaves the runway, passes for 5 seconds of the flight, and you need to remove the landing gear. At this moment the crew retracts the flaps instead of landing gear.They are not removed immediately, so the crew cannot immediately understand that something is going wrong. 15 seconds pass, maybe even 20 - something buzzes, and there is an illusion that the flaps are slowly retracting. Having given the command to retract the flaps, thinking that they are retracting the landing gear, the crew, after 15 seconds, begins to understand that there is a problem. They cannot gain altitude because they lack lift. Also, the unretracted landing gear dangles below and slows down the plane, that is, the wing lift has fallen, and the resistance has not disappeared. And then the plane starts to sink.
We assume that they had only two minutes from receiving permission to take off. 3-4 seconds pass, they release the plane from the brakes, scatter along the runway for 30 seconds, take off for another 5 seconds, then start to retract the flaps instead of the landing gear, this happens for another 15 seconds.
They begin to understand what is happening to them, literally a minute after they were allowed to take off, that is, after half of the two minutes that they were allowed to complete.Moreover, it is night, there is no visual contact with the horizon, they fly according to instruments, according to sensations. And when they realize that there is a problem, that the plane is not gaining altitude, they spend some more time understanding the situation. And now they understand thatflaps were removed instead of landing gear, and the phrase sounds: “Damn, flaps!” Its meaning is not thatthey are not removed, but in the fact that they simply do not exist. Vthis point obviously they start trying again them.
The flaps are released in exactly the same way, in the reverse order, but the same 15 seconds, and until they are released, the wing lift does not increase, and the plane falls. They sag and, trying to somehow raise the wing lift, pull the steering wheel towards themselves, go to supercritical angles of attack, an audible alarm sounds in the cockpit, and they fall.
We do not participate in the investigation, we do not examine the wreckage, we do not know what is happening there in Sochi, but some part of the information still comes to us from the media. When the day before yesterday, late in the evening, the landing gear was taken out from the bottom by a floating crane, it was clear that the landing gear was not locked. The fact is that the position of the chassis is always fixed with locks.There are locks of the retracted position, there are locks of the released position. The latter fix the landing gear in the parking lot and during taxiing, so that they do not collapse and the plane does not fall on its belly. And in flight, they are also fixed, because the landing gear is a heavy thing with wheels, and the plane rolls in flight, raises the tail, lowers it, it talks, if the landing gear is not fixed inside the niche, they will sway there and beat against the walls, against the ceiling .
On the video that we were shown on TV, it can be seen that the landing gear was not locked in the retracted position - this is, firstly, and, secondly, there were no landing gear doors. This gives reason to assume that at the time of impact on the water, the landing gear was released.
The landing gear was not locked in the retracted position and there were no flaps, with a strong impact on the surface of the water, the open racks simply tear off.
There were no flaps, with a strong impact on the surface of the water, open racks simply tear off. The video, of course, is of poor quality, reporters are not allowed into the place, but what is seen can be interpreted in this way: at the moment of impact on the water, the landing gear was released. There is also a photo of the raising part of the wing with flaps, it shows that the flaps are retracted.
It turns out that the aircraft, 2 minutes after the start of the takeoff run, has landing gear that are not locked in the retracted position, and the fragment of the flap shows that they are already folded, but it should be the other way around - wthe assi must be locked in the retracted position, and the flaps must not be fully retracted, but fully or partially extended.
I emphasize that the photo is not very high quality, the video is even worse, but nonetheless. This, of course, is the biggest mistake of the crew, I don’t want to believe it, but the phrase: “Flaps”, said by the pilots, confirms this mistake.Clarity will come when the parametric recorder is deciphered, whether there was a command to retract the flaps, and, if so, in what position they were.
According to the information that came out today, it is also clear that there is damage to the fan blades on the right engine, it is said that this is not a bird. But I think it's damage from hitting the water, because otherwise you have to assume that the plane took off with bent fan blades from Chkalovsk. This is generally something egregious, the plane, as we were told, was carefully inspected before taking off from Chkalovsk,he took off and flew for 3 hours to Sochi, and there were no problems.
I think the damage happened on impact with the water, which means the plane was listing to starboard. This suggests that either the pilots tried to somehow dodge, maneuver at the last moment, or there was a problem with the synchronism of retracting the flaps (see Version 1). If there was a roll to starboard, it means that the flaps on the left wing were released more than on the right - the left wing had a large lift and the plane capsized to the starboard side.
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— Who is responsible for technical failures in military aircraft?
- The operating organization is responsible for the maintenance of military aircraft. In this case, maintenance work are carried out by its forces, and repairs are carried out by specialized enterprises that repair aviation equipment - the rules are the same for military aircraft and for civilian ones.
- The plane fell apart into more than 1500 fragments - is this possible when hitting the water?
“You have to understand that water in such a situation is no different from concrete, and the debris fall area – 500 meters – corresponds to the situation. But we don’t know what happened next: the plane hit the tail, the tail broke off, then what remained after the separation could tumble and fly apart.
check if he is lying or not. In general, the media first reported that the bodies were wearing life jackets, and then that they were not. It was said that the landing gear was separate from the wreckage, from which it could be concluded that the plane fell into the sea, and the landing gear - on the shore, and today I read that a floating crane lifted the landing gear from the seabed. Therefore, when a person told reporters that he saw something at half past five in the morning, this information must be verified - now it is difficult to comment on it.— Some experts say that the plane was too old.
- The assigned resource for this type of aircraft is 35 years of service and 60 thousand flight hours. He served 33 years and flew less than 7,000 hours. That is, in terms of resource consumption, wear and tear of parts, he spent only 11% of it, and in terms of service life 33 years out of the allowed 35. This suggests that the car stood on the ground more than it flew. That is, suppose you bought a car and drive once a month, and consider whether it is new or not new - if you service it normally, then rather yes. The main thing here is that the flight resource in terms of the number of flight hours has been developed little, this is a completely normal aircraft, if it is serviced, treated normally, it could still fly and fly.
The flaps of the plane could cause the crash of the Tu-154 on December 25 near Sochi. This version was put forward by experts after decrypting the data of one of the black boxes.
Aircraft flaps: why, photo, why are they needed during takeoff and landing
The reason for the crash of the Tu-154 in Sochi could be the flaps. According to a preliminary analysis of the data received from one of the black boxes, the development of an emergency situation on board could begin with flaps that did not retract for some reason.
Trying to compensate for the dive moment that arose because of this, the pilots aggravated the situation to a critical one by excessively lifting the nose of the aircraft.
According to Life, citing a source close to the investigation, the experts were able to decipher the recording from the voice flight recorder without any problems. According to him, the conversation is interrupted by the fact that one of the pilots exclaims: "Flaps, s ... ah!" Then a cry sounds: “Commander, we are falling!”.
- Speed 300... (inaudible)
- (inaudible)
— Got the racks, Commander.
- (inaudible)
— Wow, e-mine!
(Sharp horn sounds)
- Flaps, s... ah, what the f***!
- Altimeter!
- We ... (inaudible)
(Ground proximity alarm sounds)
- (inaudible)
"Commander, we're falling!"
What are aircraft flaps for, photo
Flaps are called the element of mechanization of the wing. When retracted, they are an extension of the wing surface. In the released state, they depart from it with the formation of cracks. Flaps are needed to improve the carrying capacity of the wing during climb or takeoff/landing. They are also needed when flying at low altitudes.
When the flaps are extended, the curvature of the profile increases, which allows aircraft to fly without stalling at low speeds. The Tu-154M uses double-slotted flaps, while the Tu-154B uses triple-slotted ones. The flaps can be extended both automatically and by the command of the pilots from the cockpit.
According to preliminary data, the flaps worked inconsistently on board, as a result of their absence, the lift was lost, the speed was not sufficient for climbing, and the aircraft crashed.
Official data on the transcript of the records has not yet been published.
Flaps photo
Recall that on December 25, at 01:38 Moscow time, the Tu-154 aircraft of the Russian Defense Ministry took off from the Chkalovsky airfield in the Moscow region and was heading to the Khmeimim airbase in Syrian Latakia.
In Sochi, the aircraft stopped for refueling, which was not known in advance. At 05:27 Moscow time, the plane disappeared from radar a few minutes after taking off from Adler airport. Later it became known that the liner crashed in the Black Sea near the Sochi coast.
There were 92 people on board the aircraft, all of them died.
Among the victims of the disaster are 64 employees of the Alexandrov Song and Dance Ensemble and its leader Valery Khalilov, three film crews, doctor Elizaveta Glinka, who was carrying medicines to Syria, as well as Anton Gubankov, director of the Department of Culture of the Ministry of Defense, and crew members.
Published on 28.12.16 14:16According to experts, there have been cases when, instead of the "flaps-15" mode, the switch was accidentally put in the wrong position.
As I wrote earlier, the preliminary results of the decoding of the flight recorders of the Tu-154 aircraft of the Russian Ministry of Defense that crashed near Sochi showed that the development of an emergency situation on board occurred on an airliner. Journalists from Moskovsky Komsomolets asked experts to comment on what happened on board the airliner.
According to one of the experts, if there is a mismatched release of the flaps, then the jammed flap remains in the position in which it is stuck.
"That is intkbbee the system cuts off all electric motors that are used for the release and cleaning of mechanization (flaps). At the same time, this tracking system releases a serviceable flap, or removes it to the very corner at which the jammed flap remained. In this regard, some have a question: is it possible that the crashed "Tu" was so old that it was not equipped with such a system? No. I flew on this plane and I can say that only the very first Tu-154s did not have it. Later, planes with the designations Tu-154A went, then "A-1", "A-2", then - Tu-154 B, etc. The latest modification with the designation "M". And everyone had this system. So why does one of the crew members scold the flaps in his last words? I think at that moment he just realized that he had made a mistake," the specialist said.
The expert notes that in this aircraft, the switch for retracting and extending the flaps is located above the windshield of the cockpit. If the ship's commander is piloting, then the co-pilot releases the mechanization, and if the co-pilot is piloting, then the commander controls the switch.
“There are grooves in the switch where the switch is locked in three different positions: “flaps-15”, “flaps-28” and “flaps-45”. And when the commander taxis on takeoff, he gives the command: “flaps-28” The co-pilot puts them in the take-off position.The plane (this, however, depends on the flight weight) takes off from the ground at a speed of 270-290 km per hour. Then, when it needs to cross a height of 120 m and go higher, it accelerates to a speed of not less than 330 km per hour, and then a command is given to clean the mechanization. That is, from the "flaps-28" position, their switch is set to the "flaps-15" position. Meanwhile, the plane continues to accelerate. But there have been such cases - especially if the chatter is in in the air - when instead of "flaps-15" the switch was accidentally, by mistake, set to position "0". This, of course, is an assumption, but just imagine: from "28" the flaps are immediately retracted to "0". "clean wing", that is, when mechanization has already been completely removed, is not provided. the aircraft reaches a critical angle of attack, at which it is possible to stall into a tailspin. If something like this happened, then it can definitely be regarded as a crew error," he stressed.
Another expert described the possible situation on board somewhat differently. wrecked Tu-154.
“If the flaps began to retract out of sync, then the point here is not that there is not enough lift. There is enough of it. It’s just that the difference in lift on the left and right half-wing leads to the fact that the roll angle develops intensively. If you don’t immediately respond to this, then you can’t do anything further, since the speed grows and, accordingly, the difference in lift forces on the half-wings grows, and even the rudder travel is no longer enough to compensate. according to the transcript of the negotiations, which appeared in the media, everything was probably even worse there: the pilots removed the flaps instead of the landing gear ... And they killed themselves. In this case, there are no options at all ... ", he said.
