In the first part of the story, we got acquainted with the history of military and civil aviation ornithology. In the end, we will pay attention to the techniques for preventing aircraft collisions with birds, which, unfortunately, are still far from perfect.
Probably the most frugal way to protect aircraft from innocent birds is to regularly take care of the airfield. The goal is to create an appearance that does not attract birds. Therefore, there are no landfills nearby, and all household waste must be stored only in opaque bags so as not to attract too much attention to the vigilant bird's eyes. In addition, all shallow bodies of water must also be eliminated - they can become a habitat for the most dangerous, heavy and clumsy waterfowl. Naturally, the grass near the runway is regularly mowed (so that all quails do not nest) or replaced with a low clover with alfalfa. The absence of tall grass also helps to avoid the dispersal of small rodents, which are hunted by predatory birds. It is also preferable to cut down all trees and shrubs at a distance of 150-200 meters from taxiways and runways.
This is one of the directives of the International Civil Aviation Organization (ICAO), which coordinates aviation safety compliance. Further, it is more difficult. In self-respecting companies, experts examine the flora for honey plants, which attract insects, which, in turn, are a food source for birds. Often, all of the above techniques do not give a tangible effect - flocks of birds continue to fly in schools across the runway. We have to carefully examine the territory at a distance of several kilometers from the airports. Thus, in Tomsk, it was possible to suppress the deadly flights of pigeon flocks across the runway of the local airport. It turned out that hundreds of pigeons flew to feed from the nearest village to the farm. It was necessary to isolate all available feed from birds, which was the solution to the problem. By the way, it is impossible to take airports out of the wilderness from all settlements - birds consider the villages as an excellent food base and are not distracted once again by the aircraft base.
Naturally, passive methods of defense by the airfield and airports are absolutely insufficient and must be used in conjunction with active methods of deterrence. It is important to remember that only in Russia every tenth bird species is listed in the Red Book. This makes it necessary to develop special approaches to the active protection of air routes.
One of the earliest ways to scare birds away were bioacoustic devices that broadcast alarms and cries of birds of prey to feathered intruders. The first in this business were the Americans, when in 1954 they dispersed unwanted flocks of starlings with recorded bird calls of distress. A modern example is the foreign installation Bird Gard, which has a wide range of applications - from industries that are toxic to birds and agricultural land to large air transport hubs. Among the domestic analogs are the installations "Biozvuk MS" and "Berkut". The general requirements for the use of such a technique is the remoteness from the places of residence of people - the sounds emitted are very loud (more than 120 dB) and can disturb the mental balance of the inhabitants of a small village. At a distance of 100 meters, such a sound can cause a person to vomit. The "Biozvuk MS" system and a less powerful modification of the MM have been supplied to the Russian Ministry of Defense since 2017. Obviously, the Khmeimim airbase has become one of the most important targets for the use of bioacoustic scarers. Firstly, in winter, the activity of birds there, if it decreases, is insignificant, therefore, the danger of meeting with birds is practically year-round. And, secondly, the Middle East is one of the main migratory routes for birds of different types and calibers. Bioacoustic systems manufacturers remind that only panic signals for birds are not enough. Requires at least more and noise propane guns, from time to time imitating weapon shots. The robotic system "Airport Birdstrike Prevention System" from South Korean engineers, which is capable of autonomously patrolling the vicinity of the airport and military base, has become a real high-tech. In case of detection of a feathered intruder by the on-board radar, the machine scares him off with an acoustic weapon (knows the "language" of 13 bird species) and irradiates him with a laser.
However, birds are far from always ready to adequately respond to sound stimuli. So, in the late 80s in the USSR, military and civilian aviators decided to conduct an experiment and determine how quickly seagulls adapt to bioacoustic repellents. For the test site, they chose a dump near Pulkovo airport, which was like a blanket of snow from feeding gulls. They turned on scare signals. It turned out that each time a smaller number of birds reacted to the stimulus. Surprisingly, even chickens living on farms near helipads, over time, have become completely indifferent to the rotary-wing machines flying directly over them. Therefore, all tricks in bioacoustics can be effective only against non-frightened specimens.
At one time, the Air Force of the Soviet Union with such protective airfield systems reached a dead end. Every year the army lost up to 250 engines and several aircraft with pilots from collisions with birds. Here is what Major General Viktor Litvinov, head of the Air Force Meteorological Service, said in the early 1980s:
“The main reason that we have not yet achieved satisfactory results, I think, is the human factor. Some officials have not yet become imbued with a sense of responsibility for the solution of an important state task. They attribute bird collisions to a natural phenomenon and consider it a fatal inevitability. Therefore, the work of non-staff ornithological commissions of aviation units is often reduced to the fulfillment of duties assigned to meteorological units. Preventive work to prevent bird strikes is not always purposeful. The lack of reliable methods for regulating the number and behavior of birds in the areas of airfields also affects. Technical means of detecting and repelling birds do not meet modern standards. Another problem. The councils of ministers of the Union and autonomous republics, local Soviet bodies do not prevent, as prescribed, the creation of industrial and domestic waste dumps, fruit and berry plantations that cause the accumulation of birds on the areas adjacent to the airfields.
The result of such criticism was the decree of the government of the USSR, which directly stated the need to develop a set of measures to combat birds near aircraft objects. But it happened a few years before the collapse of the country …
Firecrackers, chemistry and balloons
To enhance the effect of scaring away, pyrotechnic means of the "Khalzan" rocket launcher type with the cartridge PDOP-26 (cartridge for scaring away birds) are additionally used. The device creates a real show in the sky with pops up to 50 decibels, sparks and orange smoke. The predecessors of noise gas cannons were carbide installations in which acetylene exploded. Over time, they realized that it is much safer and more convenient to explode the finished gas than to synthesize it from carbide and water. But in any case, such systems are of little use for civil airports due to their explosion and fire hazard. Since the end of the 80s, laser emitters have entered the world practice, capable of creating a situation of discomfort in birds at a distance of up to 2 km. The pioneers in this business were also the Americans, who tested the devices on the birds of the Mississippi Valley.
Banal poisoning of animals has become a cardinal way of fighting birds. This practice is not legal in all countries. So, Italy, Austria, Portugal and several other EU countries do not apply chemical exposure to birds. Avicides (bird poisons) are also banned in the United States. In Russia, such substances are not used in the aviation sector, but to protect agricultural fields. Avitrol became the main drug. He and its derivatives in the smallest concentrations cause involuntary convulsions in animals, accompanied by cries of bird terror. This is very good at scaring away the rest of the brethren in appearance. Alphachloralosis is a sleeping pill for birds used at aerodromes. The sight of fellows sleeping in arbitrary poses causes panic in the rest of the birds, suspicion of massive and fatal poisoning of the territory. As a result, winged airspace violators retreat for a long time. By the way, the technique of hanging the corpses of birds for everyone to see is also an effective deterrent. The disadvantage of using chemicals is a considerable percentage of lethality, as well as the weathering of poison from airfields.
Birds have very keen eyes. Scientists decided to turn this property against them. A bright image of the eye of a bird of prey or simply contrasting circles on the balls have become a new means of fighting birds. But only for the first time. From the memoirs of Soviet military meteorologists:
“I remember such an innovation as the“ball-eye”. The Japanese offered the USSR to buy from them an effective means of fighting birds. In the area of the runway, an inflatable balloon with the image of a hawk's eye was lifted into the air on a cable. The birds had to think that it was the eye of a predator, get scared and fly away. We tested the balloon at one of the airfields and found out that it really works. The Air Force bought a large batch of balloons from the Japanese, which they distributed among all the associations. Soon, however, it became clear that the birds get used to the presence of the "ball-eye" and eventually begin to ignore it. The use of the Japanese innovation, of course, has withered, and every self-respecting aerodrome meteorologist has unclaimed balloons at his dacha.
More precisely, the effectiveness of visual means of struggle cannot be said …
Among the many other methods of protecting aircraft (nets, rattles, radio-controlled models of birds, mirror balls, scarecrows and radars), tame birds of prey of the falcon and hawk orders stand out in their effectiveness. At the genetic level, they instill fear in most birds. For the first time, falcons and hawks entered service in the main airports and military bases of the world in the 60s, but they came to the USSR only by the end of the 80s. The neighbors in the socialist camp from Czechoslovakia helped, who created a method of training the Central Asian Saker Falcons. However, the Soviet Union did not manage to establish the practice of widespread use of winged predators in the interests of aviation. Perhaps the falcons worked effectively only in the Kremlin, driving peaceful birds away from well-groomed landscapes and flower beds. Now, most of the large air harbors in Russia use the expensive services of an ornithological service, in which falcons and hawks play the main roles. This is also not a panacea: animals get sick, shed, get tired, require specific care and training. In addition, some birds are distinguished by their fearlessness (for example, seagulls), and as soon as the predator sits on the hand of the "operator", they immediately return to their old place.
The confrontation between the airplane and the birds is far from its final. With each new step of a person, birds find ways of adaptation and again return to their usual habitat. And the man, as he was superfluous in the air, remained so.