Many people are afraid of flying. Psychologists say that there is even such a thing as "aerophobia". Patients with this diagnosis experience real horror at the mere thought of taking to the air. The strongest negative emotions are caused by air pockets and turbulence. Such moments are unpleasant even for those who do not experience fear of flying. However, the pilots claim that in fact this is quite a common natural phenomenon that can be explained in scientific language, and it will not bring any trouble to the passengers of the airliner. Today we decided to tell you what an air pocket really is, and whether it is worth being afraid of.
Term Explanation
It is quite difficult for an ordinary person to understand what an air pocket actually is. Everyone understands that there are no highways and pavements in the sky, and therefore there can be no holes. For example, when it comes to driving a car, it is absolutely clear to anyone that there may be an obstacle or a hole on the road that an experienced driver can cut. But what if you get into an air pocket? Can it be bypassed? And how dangerous is she? We will answer all these questions in the following sections of the article. But let's understand this difficult topic gradually.
Scientists have long known that air currents are not uniform. They have different directions, temperatures and even densities. All this affects airliners following certain routes. In the case when the plane encounters streams of lower temperature on its way, a complete illusion of a short-term fall is created. Then we usually say that the ship has fallen into an air pocket. However, in reality, this is just an illusion that can be easily explained with the help of modern science.
Downstream and Upstream
To understand how air pockets form, it is necessary to have a complete understanding of the movement of air currents. According to the laws of physics, heated air always rises, and cooled air falls down. Warm currents are called ascending, they always tend upward. And cold air is considered to be descending, and like a funnel it pulls down everything that comes in its way.
It is because of the movement of these flows that air pockets so unloved by passengers are formed during the flight. They make travelers experience very unpleasant sensations that many cannot forget for a long time.
The principle of the formation of air pockets
Despite the fact that the modern aircraft industry has long equipped its new liners with an abundance of technological innovations designed to make flying comfortable and safe, so far no one has managed to save passengers from the discomfort caused by descending air masses. So, the plane got into an air pocket. What happens to him at this moment?
Even when flying in good weather conditions, an airliner can encounter cold air. Since it is descending, it begins to significantly slow down the rate of ascent of the aircraft. It is noteworthy that in a straight line it goes with the same indicators, but it loses a little height. This usually only lasts for a few moments.
The airliner then meets the updraft, which begins to push it upwards. This allows aircraft return to the previous altitude and continue the flight in the normal mode.
Feelings of passengers
For those who have never been in air pockets, it is quite difficult to understand how the passengers of the aircraft feel. Usually people complain that they experience stomach cramps, nausea rising to the throat, and even, lasting a fraction of a second, weightlessness. All this is accompanied by the illusion of falling, which is perceived as realistic as possible. The totality of sensations leads to uncontrollable fear, which in the future does not allow most people to calmly endure flights and causes aerophobia.
Is it worth it to panic?
Unfortunately, not a single highly professional pilot will be able to get past the air pocket. It is impossible to fly around it, and even the brand and class of the aircraft will not be able to protect passengers from unpleasant experiences.
Pilots claim that the moment the plane hits the downdraft, it loses control for a while. But you should not panic because of this, such a situation lasts no more than a few seconds and, apart from unpleasant sensations, does not threaten travelers with anything.
However, you need to know that in the air pocket the airliner is under serious pressure. At this point, the plane hits "chatter" or turbulence, which, in turn, adds to the frightened passengers' discomfort.
Briefly about turbulence
This phenomenon gives travelers a lot of inconvenience, but in fact it is not dangerous and cannot lead to an airliner crash. It is believed that the loads on an airplane during turbulence are no higher than on a car that is moving on a rough road.
A turbulence zone is formed when air flows with different speeds meet. At this point, vortex waves are formed, which cause "chatter". It is noteworthy that turbulence occurs regularly on some routes. For example, when flying over mountains, the plane always shakes. Such zones are quite long, and the “chatter” can last from several minutes to half an hour.
Causes of turbulence
We have already talked about the most common reason for the appearance of "bumpiness", but, in addition to this, other factors can also cause it. For example, an air liner flying in front often contributes to the formation of vortices, and these, in turn, form a zone of turbulence.
Near the surface of the earth, the air warms up unevenly, which is why vortex flows are created, which cause turbulence.
It is noteworthy that pilots compare flying in the clouds to highway traffic with potholes and potholes. Therefore, in cloudy weather, passengers most often experience all the "charms" of a flight in a shaking plane.
The dangers of turbulence
Most passengers seriously believe that turbulence can break the cabin's airtightness and lead to a crash. But in fact, this is the safest phenomenon of all possible. The history of air transportation does not know a case when getting into a "bump" would lead to fatal consequences.
Aircraft designers always put a certain margin of safety into the body of the aircraft, which will quite calmly withstand both turbulence and thunderstorms. Of course, such a phenomenon causes anxiety, unpleasant emotions and even panic among passengers. But in fact, you just need to calmly wait out this moment, not succumbing to your own fear.
How to behave during the flight: a few simple rules
If you are very afraid of flying, and thoughts about air pockets and turbulence make you feel terrified, then try to follow a number of simple rules that will greatly ease your condition:
- do not drink alcohol during the flight, it will only aggravate unpleasant emotions;
- try to drink water with lemon, it will relieve attacks of nausea when it enters the air pockets;
- before the trip, set yourself up in a positive way, otherwise you will always be tormented by forebodings and negative emotions;
- be sure to fasten your seat belts, passengers may be injured during the passage of the turbulence zone;
- if you are very afraid of flying, then choose larger aircraft models that are less sensitive to all sorts of shaking.
We hope that after reading our article, your fear of flying will become less acute, and your next air travel will be easy and enjoyable.
Specialists have reconstructed the Tu-154 take-off scheme according to the testimony of the flight recorder, Kommersant newspaper reports. The result seemed unusual to the experts - it turned out that when the navigator warned the pilots about the fall, they did not react to it in any way. The sensors of the liner did not record the logical movement of the steering wheel "towards itself" in the current situation.
ON THIS TOPIC
Moreover, a source close to the investigation said that "until the collision with water, they responded to the crew's control actions in a timely and regular manner." A pilot's emotional statement about the flaps may indicate a non-critical delay in the order to retract them, but not a technical malfunction.
Aviation experts suggested that the behavior of the pilots was strongly affected by the fact that the flight was made at night. "A few seconds after leaving a well-lit and marked lane, you cross a well-lit coastline and immediately you find yourself as if in a black hole, "said one of the experts. In such a situation, the pilot must trust only the readings of the sensors, and not his own vestibular apparatus.
However, the on-board systems of the Tu-154 recorded that the commander manually corrected the flight path for a long time. This indicates his loss of orientation. Many experts criticize the inaction of the co-pilot Alexander Rovensky, but his behavior is explained by the fear of taking the helm from the senior major Volkov.
However, a number of experts deny the "illusory" version of the fall of the Tu-154. They explain the resulting scheme of the tragedy by a malfunction of the parameter registration system.
We add that the behavior of the pilot's body has long been studied by such a science as aviation psychology. However, experts still have not been able to establish why the captain of the aircraft instinctively violates the flight path. Experts say that fatigue, stress and malaise can contribute to disorientation. According to statistics, every tenth plane crash in the world is due to illusions.
“Ladies and gentlemen, this is your captain speaking. We have a small problem. All four engines stopped. We're doing everything damn possible to get them up and running again. I'm sure you're not entirely in distress."
There are a lot of real dangers to flying airplanes. All of them are well studied. Dozens of cases of aircraft collisions with birds a year, as a rule, do not lead to catastrophes or accidents at all, and even more so do not serve as a reason for bans to restrict flights to countries where there are birds. Cumulonimbus clouds are a deadly threat to aircraft, yet hundreds of aircraft daily simply bypass these pockets at a safe distance (about 50 kilometers in the middle between clouds, or 15 kilometers away from a single cloud). To list such phenomena is not the topic of the material, believe me, their presence in nature does not reduce the overall safety of flights.
For a detailed clarification of the issue, I talked on the phone with Valery Georgievich Shelkovnikov, Member of the Board of the World Aviation Safety Foundation, and President of the Consultative and Analytical Agency " Flight Safety ". I present the results of our private conversation below in my own words and from myself, because there is no way to separate the words of an expert from the words of a journalist:
The eruption of the Eyjafjallajokull volcano and subsequent events related to the cancellation of flights in Europe amused me a lot. I am not against aviation security at all. Moreover, if a person can even joke about this topic, then he still does not know what an aviation accident is. However, I will continue the topic. The mythologization of volcanic eruptions and the hysteria of the press forced airlines to stop or postpone flights on those state territories where "clouds" of volcanic ash fell.
So was there a real danger to flights, or was there a collective air hysteria, the beginning of which was laid by journalists, and then the domino effect worked? Let's try to figure it out.
Indeed, the ingress of a large amount of abrasive dust into aircraft engines (and it does not matter what origin) can cause a fire in the engines due to instantaneous overheating and subsequent destruction of the turbine bearings. At a rotational speed of several thousand revolutions per minute, they will simply melt from friction. Therefore, when an aircraft hits a column of volcanic dust, such a situation is quite possible.
Another thing is the special structure of volcanic dust. In addition to rock particles thrown out by the explosion, it also consists of amorphous particles (by the way, glass is also amorphous) of extremely irregular shape. If you look at volcanic dust under a microscope, you can clearly see that it consists of "ribbons", "stars" and other particles that have a very large surface with a small weight. Those. thanks to this feature, it can remain in the air many times longer without dissipating. For due to electrification and other interactions of ash particles, such clouds dissipate extremely reluctantly.
Also, its feature is its "stickiness", i.e. the ability to stick to various objects or clog various holes. Moreover, the particles, being excellent nuclei of condensation, after a while become absolutely outwardly indistinguishable from an ordinary cloud.
Another thing is that even at a distance of "hundreds" of kilometers from the volcano, the dust becomes so rare and fine that the probability of an aircraft failure for this reason becomes only "theoretically" possible. And at a distance of a thousand kilometers or more, volcanic dust can only slightly cloud the air, which is nevertheless clearly visible to the naked eye, because sunrises and sunsets become most beautiful due to the special refraction of the sun's rays in the dusty air.
Those who have been to Egypt are well aware of sandstorms over Hurghada airport. Suspension of sand in the air, and especially the concentration and size of particles in the air, are several orders of magnitude higher than the concentration of dust over Europe. And in Australia, flights in the conditions of global dust storms are stopped only in cases of extreme deterioration in visibility. These examples can be continued indefinitely. And now, attention!!! The only difference is that, unlike volcanic dust, the rest of the dangerous phenomena are well studied, and there are clear recommendations for avoiding them, as well as a clear regulation of prohibitions and permits “depending on”.
Let me now present my consistent version of what happened.
The influence of volcanic ash on the flight of aircraft has always been an understudied thing. Of course, volcanologists stubbornly studied each eruption, and meteorologists had a fairly clear idea of the direction and speed of ash expansion, but no one betrayed the fate of these particles in the slightest, because already a few hundred kilometers from the volcano in the direction of the wind, the ash already represented nothing more than an interesting optical illusion. Yes, and civil aviation knew only a couple of cases before that, when planes actually fell into very dense clouds of ash, and because of this, engines stopped and other unpleasant things happened. Of course, volcanic ash as a dangerous phenomenon was included in all textbooks and instructions.
In practice, both pilots and air traffic controllers were rather derisive about these points of instruction and did not study them well enough. Because of the rarity and exoticism. And it is these same aviation officials who grew out of former pilots and air traffic controllers, practically did not allocate money for the study of these phenomena in the interests of civil aviation that instead of "accurate" knowledge instantly overgrown with myths and legends. In general, there was some frank nonsense in meteorology. Thanks to blind faith in "computers" and "satellites" around the world, the number of weather stations with "live" people has decreased by about 60% -70%. And the existing "automated systems" can only build hypothetical mathematical models that have nothing to do with the real state of affairs.
So, journalists inflated the topic, and the international aviation authorities, in particular Eurocontrol, instantly fell for it. Not only that, when aviation officials began to turn to numerous experts in this field, they (experts) rather vindictively reported something like this: “This phenomenon is certainly dangerous, but not well understood. Our equipment practically does not allow us to distinguish clouds of dangerous concentration of volcanic dust from ordinary ones. So where these clouds are, and whether they actually exist, we do not know.
And then it got even funnier. The danger zone was actually quite local (several hundred kilometers in diameter and duration), but in reality, hundreds and hundreds of thousands fell into the “closure” zone square kilometers earth and water surfaces. At the same time, all levels from “0” to 35,000 feet (approximately 12 km) were also absolutely closed in altitudes, although even the most reinsurers predicted a dangerous closure of altitudes only from altitudes of 22,000 feet. In short, the flight ban took on an absolute character, because even its initiators could no longer do anything. The domino effect worked.
In addition, an absolutely unexpected thing was revealed. It was possible to fly in ash-free zones, and in some cases deviations from the route or an increase in its duration by several hundred kilometers did not play any role, but modern automated systems simply were not able to reschedule en masse. Yes, and it became impossible to do it individually. Automation, automation, and more automation. Specialists in "manual" scheduling simply died out like dinosaurs, and modern airlines simply do not have such specialists. Those who are in the subject should imagine that drawing up even a regular class schedule at a university is already an action between science, art and mysticism. There was no talk of redrawing the timetable over Europe. There was a mess. I absolutely do not condemn any measures related to flight safety, but admit that in the 21st century it is quite funny to close half a continent for the sake of one mountain with smoke. Let them be strong.
The "American" help only caught up with additional horror in Europe, and finally deprived the European aviation officials of the remnants of their will.
As for Russia as part of Europe, there was no panic at all. The fact is that the long-term study of the Kuriles (as a zone of constant eruptions) has brought a sufficient amount of knowledge and skills to determine the dangers of flights. Therefore, Russia flew on its territory without problems.
Although in Russia the so-called “Storm Ring of Alerts” was previously destroyed, i.e. hundreds and hundreds of weather stations were closed, where underpaid weather forecasters sat, and the accuracy of predictions and warnings about dangerous phenomena was unprecedentedly high.
As for the “underfunded” scientists, we can immediately confidently say that they will be allocated very large amounts of money for research, as compensation for past torments. But the fact that this will violate world harmony, because this money will be taken away from other areas - this is really bad. Business and charity don't go well together, do they?
Nevertheless, that the leading scientists immediately wrote off and phoned each other and worked out a common position, I have no doubt about it. Internet, mobile connection and e-mail in terms of communications - work wonders. Moreover, I have such information. Not for nothing that I, at least for a short time, but stayed a geologist-geophysicist. So business will receive prices from science in full.
And as an epilogue for those who took my words like “funny” and “funny” literally, I quote a short excerpt from Sergey Melnichenko’s article “Flight History” british airways nine".
They were able to see the runway lights through a small scratch on the windshield, but the aircraft's landing lights were not on. After landing, they were unable to taxi because the apron lighting caused their windshields to become frosted. The city of Edinburgh was waiting for a tugboat to pull it off the runway...
It was subsequently determined that the aircraft had entered an ash cloud. Since the ash cloud was dry, it did not appear on the weather radar, which can only reflect the moisture in the clouds. The cloud acted as a sandblasting machine and made the surface of the windshields matte. Once in the engines, the ash melted in the combustion chambers and settled on the inside of the power plant.
Since the engines began to cool down due to their stop, after the aircraft left the ash cloud, the melted ash began to solidify and began to fly out of the engines under the pressure of air, which allowed them to be started again. The restart was made possible due to the fact that one of the on-board batteries remained in working condition.
All 263 people on board survived.
Take care of yourself. Viktor Galenko, air traffic controller, navigator, geologist-geophysicist
According to Eurocontrol, on April 18, 2010, approximately 5,000 flights were recorded in European airspace. For comparison: before the volcanic eruption in Iceland on Sunday, there were about 24,000 flights. Thus, air traffic fell by about 6 times. About 63,000 flights have been canceled since April 15. Below is a table with data on the decrease in the number of flights in European airspace:
Currently, air traffic services are not provided for civil aviation aircraft in most countries in Europe, including Austria, Belgium, Croatia, Czech Republic, Denmark, Estonia, Finland, almost all of France and Germany, as well as Hungary, Ireland, northern Italy, the Netherlands , Norway, Poland, Romania, Serbia, Slovenia, Slovakia, northern Spain, Sweden, Switzerland and the UK.
In some countries on this list, the top air space open due to the spread of the ash cloud, however, given the complete closure of the airspace over the territory of other countries, it is not possible to use the permitted sections of the upper airspace.
The airspace of such territories and countries as southern Europe, including part of Spain, Portugal, South part The Balkans, southern Italy, Bulgaria, Greece and Turkey remain open with normal air traffic.
Approximately 30% of the total number of scheduled flights will be performed today over 50% of the total territory of Europe.
As of the morning of April 19, all air zones of Ukraine are open. Airports in Ukraine for the departure and arrival of aircraft operate as normal, but a number of airports in Europe remain closed. It is allowed to operate flights according to the rules of visual flights before nightfall. About further possible changes in the airspace of Ukraine due to the movement of a cloud of volcanic ash (volcanic eruption in Iceland) will be informed. Ukrainian airlines report that flights are not operated only to closed airports in Europe, to all open airports world air traffic resumed.
The video was made using the Schlieren method for studying shock waves.
NASA has released footage of a T-38 Talon training aircraft flying at supersonic speed against the background of the Sun. It was made using the Schlieren method to study shock waves generated at the edges of an aircraft airframe. Pictures and videos of shock waves are needed by NASA specialists for research that is being conducted as part of a project to develop a "quiet" supersonic aircraft.
The Schlieren method is one of the main methods for studying air flows in the design and testing of new aircraft.
This method of photography makes it possible to detect optical inhomogeneities in transparent refractive media. Schlieren photography uses special lenses with a cut-off aperture.
In such cameras, direct rays pass through the lens and are concentrated on the cut-off diaphragm, which is also called the Foucault knife. In this case, the reflected and scattered light is not focused by the lens on the knife and falls on the camera matrix. Due to this, the attenuated light scattered and reflected by refractions in the air is not lost in direct rays.
The shock waves are clearly visible in the published video. They are areas in which the pressure and temperature of the medium experience a sharp and strong jump. Shock waves are perceived by an observer on the ground as an explosion or as a very loud bang, depending on the distance to the supersonic object.
The sound of the explosion from shock waves is called sonic boom, and it is he who is one of the main obstacles in the development of supersonic passenger aviation. Currently, aviation regulations prohibit supersonic aircraft flying over populated parts of the land.
Aviation authorities may authorize supersonic flights over populated areas of land if the perceived noise level passenger aircraft will not exceed 75 decibels. To make existence civil supersonic aviation possible, developers today are looking for different technical ways to make new aircraft "quiet".
When flying at supersonic speeds, an aircraft generates a lot of shock waves. They usually occur at the tip of the nose cone, on the leading and trailing edges of the wing, on the leading edges of the tail assembly, in the areas of the swirlers of the flow and on the edges of the air intakes.
One way to reduce the perceived noise level is to change the aerodynamic design of the aircraft.
In particular, it is believed that the redesign of some elements of the airframe will make it possible to avoid sharp pressure surges at the front of the shock wave and sharp pressure drops in its rear part, followed by normalization.
A shock wave with sharp jumps is called an N-wave, since on the graph it resembles this particular letter of the Latin alphabet. It is these shock waves that are perceived as an explosion. The new aerodynamic design of the aircraft will have to generate S-waves with a smooth and not as significant pressure drop as that of the N-wave. It is assumed that S-waves will be perceived as a soft pulsation.
The development of a technology demonstrator for a “quiet” supersonic aircraft as part of the QueSST project is being carried out by the American company Lockheed Martin. The work is carried out by order of NASA. In June of this year, the preliminary design of the aircraft was completed.
It is planned that the first flight of the demonstrator will take place in 2021. The "quiet" supersonic aircraft will be made single-engine. Its length will be 28.7 meters. He will receive a glider, the fuselage and wing of which outwardly resemble an inverted aircraft. The QueSST will be equipped with a conventional vertical keel and horizontal rudders for maneuvering at low flight speeds.
At the top of the keel, a small T-tail will be installed, which will "break" shock waves from the bow and cockpit canopy. The nose of the aircraft will be significantly lengthened to reduce drag and reduce airframe drops where shock waves can form during supersonic flight.
QueSST technology involves the development of such an aerodynamic design of the aircraft, on the edges of which the smallest possible number of shock waves would be formed. In this case, those waves that will still be formed should be much less intense.
Small unmanned aerial vehicles are becoming more common every year - they are used in filming TV shows and music videos, for patrolling territories, or just for fun. Drones do not require special permission, and their cost is constantly decreasing. As a result, the aviation authorities of some countries decided to study whether these devices pose a danger to passenger aircraft. The results of the first studies turned out to be contradictory, but in general, regulators came to the conclusion that flights of private drones should be taken under control.
In July 2015 the aircraft Lufthansa airlines, who was landing at Warsaw airport, almost collided with a multicopter, flying at a distance of less than a hundred meters from it. In April 2016 the pilots passenger aircraft British Airways, which landed at London airport, reported to the dispatchers about the collision with the drone during the landing approach. Later, however, the investigation concluded that there was no drone, and what the pilots took for it was most likely an ordinary package lifted by the wind from the ground. However, already in July 2017, at the British Gatwick airport, the plane almost collided with a drone, after which the controllers were forced to close one runway for landing and redirect five flights to reserve lanes.
According to the British research organization UK Airprox Board, in 2016 in the UK there were 71 cases of dangerous proximity of passenger aircraft with drones. In aviation, a close proximity is considered to be an aircraft approaching another aircraft at a distance of less than 150 meters. Since the beginning of this year, there have already been 64 cases of drones approaching aircraft in the UK. In the United States, aviation authorities registered just under 200 cases of dangerous proximity last year. At the same time, the aviation authorities still have a poor idea of how dangerous small drones can be for passenger aircraft. Some experts have previously suggested that a collision with a drone for a passenger liner would be no more dangerous than a regular collision with birds.
According to Aviation Week & Space Technology, since 1998, 219 people have died worldwide due to mid-air collisions with birds, and a significant number of them flew in small private jets. At the same time, airlines around the world spend a total of $625-650 million annually to repair damage to passenger aircraft due to bird strikes. Incidentally, in general passenger liners are considered resistant to direct hit by birds. During the development and testing of new aircraft, special checks are even carried out - the aircraft is fired upon with the carcasses of various birds (ducks, geese, chickens) to determine its resistance to such damage. Checking the engines for throwing birds into them is generally mandatory.
In mid-March last year, researchers from the American George Mason University, in which they announced that the threat of drones to aviation is greatly exaggerated. They studied the statistics of aircraft strikes with birds from 1990 to 2014, including episodes that ended in human casualties. As a result, scientists came to the conclusion that the real probability of a dangerous collision of a drone with an aircraft is not so great: only one case in 187 million years should end in a large-scale catastrophe.
To try to determine whether drones are indeed a threat to passenger aircraft, two independent studies were commissioned in 2016 by aviation authorities in the European Union and the UK. The engineers who conduct these studies bombard various aircraft fragments with drones of various designs or their parts in order to cause real damage that passenger aircraft can receive in a collision. In parallel, mathematical modeling of such collisions is carried out. Research is carried out in several stages, the first of which has already been completed, and the results are presented to customers. As expected, after the completion of the work, the aviation authorities will develop new rules for the registration and operation of drones by private individuals.
Drone crashes into the windshield of a passenger plane during testing in the UK
Today at different countries There are no unified rules for flying drones. For example, in the UK it is not required to register and license drones weighing less than 20 kilograms. At the same time, these devices must perform flights in the line of sight of the operator. Private drones with cameras cannot fly up to people, buildings and cars at a distance closer than 50 meters. In Italy, there are practically no special rules for drones, except for one thing - drones cannot be flown by a large crowd of people. And in Ireland, for example, all drones weighing more than one kilogram must be registered with the country's Civil Aviation Authority. By the way, in the European Union, Ireland is one of the ardent supporters of tightening the rules for the use of drones.
Meanwhile, while in Europe they plan to tighten the screws, in the United States, on the contrary, they intend to make drone flights more free. So, at the beginning of this year, the US Federal Aviation Administration came to the conclusion that light consumer quadrocopters do not pose a big threat to aircraft, although their flights near airports are unacceptable. In February, US companies 3DR, Autodesk and Atkins have already received permission to operate drone flights at the world's busiest airport - International airport Hartsfield-Jackson Atlanta, which annually passes through itself about a hundred million passengers. Here, quadcopters were used to compile three-dimensional maps of the airport in high resolution. They flew in the line of sight of the operator and under the control of air traffic controllers.
The results of the study were first published by a working group of the European Aviation Safety Agency in October last year. These researchers concluded that amateur drones do not pose a serious threat to passenger aircraft. The members of the working group during their work focused on studying the consequences of air collisions between passenger aircraft and drones weighing up to 25 kilograms. For the study, drones were divided into four categories: large (weighing more than 3.5 kilograms), medium (up to 1.5 kilograms), small (up to 0.5 kilograms) and “harmless” (up to 250 grams). For each category, experts determined the degree of danger, which was assessed on a five-point scale: 1-2 - high, 3-5 - low. Devices that received four or five points were considered safe.
To determine the degree of danger, the researchers used data on the flight altitudes of vehicles by category, took into account the likelihood of their appearance in the same airspace with aircraft, as well as the results of computer and full-scale tests of the collision of drones and airliners. In addition, the individual degree of danger was assessed for each unmanned vehicle on four points: damage to the hull, threat to the life of passengers, threat to the life of the crew, threat of violation of the flight schedule. To simplify the assessment, the researchers conducted calculations for aircraft flying at a speed of 340 knots (630 kilometers per hour) at an altitude of three thousand meters or more and at a speed of 250 knots at a lower altitude.
Based on the results of all calculations, the participants of the European working group came to the conclusion that small drones at an altitude of up to three thousand meters practically do not pose a threat to passenger aircraft. The fact is that such devices to a great height, where they can collide with an aircraft, are extremely rare. In addition, they have a very small mass. Medium drones, according to experts, do not pose a serious threat to airliners. Only if the device weighs 1.5 kilograms (such a mass has most of amateur drones) will collide with an aircraft at an altitude of more than three thousand meters, it may threaten flight safety. Large devices are recognized as dangerous for passenger aircraft at all flight altitudes.
According to the results of full-scale tests, it turned out that in the event of a collision with drones, the windshields of the airliners, nose cones, wing leading edges, and engines can receive the most damage. In general, the damage from drones weighing up to 1.5 kilograms can be comparable to the damage from birds that aircraft regularly encounter in the air. Now, European experts are preparing for an expanded study. This time, the damage that drones can cause to the engines of passenger aircraft will be studied, as well as the likelihood of batteries falling into technological holes.
By the way, earlier scientists from the Virginia Polytechnic University conducted computer simulations of situations in which various drones fall into a working aircraft engine. The researchers concluded that vehicles weighing more than 3.6 kilograms pose a serious danger to engines. Once in the engine, they will destroy the fan blades and collapse themselves. Then the fragments of the fan blades and the drone will fall into the external air circuit, from where they will be thrown out, as well as into the internal circuit - the compressor, the combustion chamber and the turbine zone. The speed of debris inside the engine can reach 1150 kilometers per hour. Thus, in a take-off collision with a 3.6 kilogram drone, the engine will completely stop working in less than a second.
Meanwhile, the results of the British study were summed up in the middle of this year - in July, the company QinetiQ, which carried out the work, handed over the report to the National Air Traffic Control Service of Great Britain. The study, conducted by a British company, used a specially designed air gun that fired drones and their parts at predetermined speeds at the front of decommissioned planes and helicopters. For shooting, quadrocopters weighing 0.4, 1.2 and 4 kilograms, as well as aircraft-type drones weighing up to 3.5 kilograms, were used. Based on the results of the shooting, experts came to the conclusion that any drones are dangerous for light aircraft and helicopters that do not have a special certificate of protection against bird strikes.
Bird-proof passenger aircraft can be seriously damaged by drones when flying at cruising speeds that range from 700 to 890 kilometers per hour. The researchers attributed the destruction of the windshields in a collision with heavy parts of the drones - metal body parts, a camera and a battery - to serious damage. These parts, breaking through the windshield, can fly into the cockpit, damage the control panels and injure the pilots. Dangerous for the liners were considered devices weighing from two to four kilograms. It should be noted that passenger aircraft develop cruising speed already at high altitude(usually about ten thousand meters), which amateur drones are simply unable to climb.
According to QinetiQ, drones weighing four kilograms can be dangerous for passenger aircraft at low flight speeds, such as when landing. At the same time, the severity of damage to the aircraft largely depends on the design of the drone. So, during the tests, it turned out that drones with a camera placed on a suspension under the body have a small chance of breaking through the windshield of a passenger aircraft. The fact is that in a collision with glass, the camera on the suspension will first hit, and then the body of the drone. In this case, the camera and its suspension will play the role of a kind of shock absorber, taking on part of the impact energy. The UK aviation authorities, who are pushing for a drastic tightening of drone regulations, are expected to order an additional study.
Some of the drones that are being mass-produced today already have the geofencing function. This means that the device is constantly updating the database of areas closed to drone flights. In such a zone, the drone simply will not take off. However, in addition to serial devices, there are home-made drones that can fly into the airspace of airports. And there are quite a few of them. In general, so far not a single case of a collision between an aircraft and a drone has been registered, but this is just a matter of time. And even if small drones do not pose a serious threat to passenger aircraft, they can still have a negative impact on aviation, increasing the already considerable costs for companies to repair liners.
Vasily Sychev
