Bird Strikes

Underestanding the risk factors of damage will be helpful to mitigate damage of bird strike. Planning for preventing bird strike evidence need to risk factors and relation of these factors to level of damage. Hence, the goal of this paper is extracting the risk factors by consideration of damage level imposed on helicopters. The data source of the current research is the Federal Aviation Administration Wildlife Strike Database which was gathered for about twenty years. In this paper, we used four kind of decision tree algorithms included C5.0, CART, C&R TREE, and QUEST to extract damage level of bird strike (D, S, M, and N that demonstrate of destroyed, substantial, minor, and not defined) on helicopters. The results demonstrated that bird size, helicopters type, phase of flight, speed, and type of engine are the most important risk factors causing damage to helicopters, respectively. Finally the research concludes with some suggestions to reduce damage of bird strike on helicopters.

Bird strike Simulation helps in assuring aircraft safety, in eliminating cost & effort
required for practical tests. There has been significant research done on various ways of
doing bird strike simulation, till date Aerospace & defense Industry is concerned with two key
issues 1.Comparative assessment of available methods 2. A FE model for fastener failure and
fastener hole embrittlement. Current paper addresses relevant issues for today’s industry
towards a universally accepted method of bird strike analysis Finite element based
computational methods. First part of current research aims at bring out comparison between
analysis methods along with their pros and cons, the Explicit analysis capabilities of Abaqus
were used for modeling the phenomenon using three methods LAGRANGIAN, COUPLED
LAGRANGIAN-EULERIAN (CEL) and SMOOTH PARTICLE HYDRODYNAMICS (SPH).
Results are compared with published literature based on the standard experimental data.
Critical parameters like HUGONIOT pressure and Stagnation pressure are compared from
each study. Merits in all the three methods and bird models are presented with a view to
guide the user in choosing an appropriate method depending on time and resource
availability. A first of its kind Bird Strike Simulation Index (BSSI) proposed with FEM setup
time, run time and accuracy as parameters, BSSI will be a holistic guidance for industrial
user.
Second part of the paper deals the most challenging issue of fastener modelling for dynamic
loads. Analysis of bird impact modeling onto metallic riveted panels, which are typically
idealized models for many practically used airframes structures like wing, flap, trailing edge,
leading edge, are done using pure Lagrangian and SPH method. In high velocity bird strike
scenario, fasteners will experience both shear and tensile loads and failure of aircraft
structures are also governed by fastener failure modes. The fasteners behavior is modeled to
simulate the failure due to shear load, tensile load and combined loads. Tensile and shear
damage modes are simulated by supplying stiffness values in all connectors. This was possible
because large variety of fastener modeling methods available in Abaqus. Results are in good
agreement with published experimental results. In reality aircraft components usually contain
large number of fastener holes which will significantly define the failure behavior of
components of assembly due to micro level embritlement around fastener hole. A first of its
kind methodology for fastener hole and fastener damage is implemented which could
successfully interlinked to the global impact failure with local micro embritlement.

Collision with buildings is a major threat to birds that provokes the death of millions of birds every year in built-up areas. Despite its magnitude, this phenomenon remains poorly studied in Europe. We studied bird-window collisions during postnuptial migration in the city of Tarragona (NE Spain). We surveyed a 15-m-high residential building in the city centre with a reflective façade for 189 days during postnuptial periods in 2012– 2015. We found 172 dead birds belonging to 15 species, most of them migratory. Blackcaps Sylvia atricapilla, Reed Warblers Acrocephalus scirpaceus and Pied Flycatchers Ficedula hypoleuca were the commonest casualties, representing 72% of all recovered bird corpses. Once the uneven sampling effort between days and years was corrected for, we estimated that the total number of fatalities during the study period was 350 birds (SE = 22.2). However, this figure is probably an underestimate due to certain biases in sampling carcasses in a city including collection by pedestrians or removal by cleaning services and owners. Overall, there was a patent seasonal pattern to the collisions, with a peak around 1 October, probably reflecting the timing of migration in the species present at the site. There were no differences in either age, sex or biometrics between the birds found in Tarragona and those trapped on the same days at a ringing station in the Ebro Delta, 60 km to the south-west. This suggests that the probability of collision affected all migrants in a uniform fashion. Our study demonstrates for the first time that bird collisions with buildings are a serious threat to migrants in the Mediterranean, a key area for bird migration in Europe.

Key words: bird collision, glasses, reflectivity, migration, mortality, Tarragona, NE Spain.

ÖZET:
Küreselleşme ve teknolojide yaşanan hızlı gelişmeler nedeniyle dünyada sivil havacılık sektörü giderek
büyümektedir. Bu nedenle artan hava trafiğine bağlı olarak kuş ve yabani hayvanların uçaklarla çarpma
sayısı artmaktadır. Yüksek hızla giden bir uçak ile bir kuş ya da kuş sürüsü arasındaki çarpışmayı ifade
eden kuş çarpması kavramı, İngilizce literatürde ‘’bird strike, bird hit ve bird ingestion’’ kavramlarıyla
tanımlanmaktadır. Kuş çarpması, ani bir şekilde meydana gelerek uçağın yapısında ciddi hasarlara neden
olur ve uçuş güvenliği için doğrudan bir tehdit oluşturur. Ayrıca, kuş çarpması olaylarından dolayı hava
yolu şirketleri milyonlarca dolar maddi zarara uğramakta ve uçuşlar ertelenmekte ya da iptal
edilmektedir. Kuş çarpması olaylarını en aza indirmek için kapsamlı önlemler almak hava yolu işletmeleri
için kaçınılmazdır. Bu araştırmada konu ile ilgili literatür çalışması yapıldıktan sonra, 1990 ve 2015 yılları
arasında Amerika kökenli sivil uçakların karışmış oldukları kuş ve yabani hayvan çarpmaları
incelenmiştir.
Anahtar Kelimeler: Kuş Çarpması, Kuş Yutması, Kuş-Uçak Çarpışması

ABSTRACT:
Due to globalization and rapid developments in technology, civil aviation sector is growing in the world.
For this reason, the number of strikes of birds and wild animals with airplanes is also increasing due to
increased air traffic. The concept of bird strike, which expresses the collision between an airplane flying
at high speed and a bird or bird flock is described in the English literature as "bird strike, bird hit and bird
ingestion". Bird strike occurs suddenly and causing serious damage to the aircraft structure and posing a
direct threat to flight safety. In addition, airline companies have suffered millions of dollars in financial
loss due to bird strikes and flights have been postponed or canceled. Comprehensive measures to
minimize bird strike incidents are inevitable for airline companies. In this study, birds and wildlife strikes
of US civilian aircrafts between 1990 and 2015 were investigated after the literature study on the
subject was made.
Key Words: Bird Strike, Bird Ingestion, Bird-Aircraft Collision

Synopsis Each year, billions of birds collide with large human-made structures, such as building, towers, and turbines, causing substantial mortality. Such bird-strike, which is projected to increase, poses risks to populations of birds and causes significant economic costs to many industries. Mitigation technologies have been deployed in an attempt to reduce bird-strike, but have been met with limited success. One reason for bird-strike may be that birds fail to pay adequate attention to the space directly in front of them when in level, cruising flight. A warning signal projected in front of a potential strike surface might attract visual attention and reduce the risks of collision. We tested this idea in captive zebra finches (Taeniopygia guttata) that were trained to fly down a long corridor and through an open wooden frame. Once birds were trained, they each experienced three treatments at unpredictable times and in a randomized order: a loud sound field projected immediately in front of the open wooden frame; a mist net (i.e., a benign strike surface) placed inside the wooden frame; and both the loud sound and the mist net. We found that birds slowed their flight approximately 20% more when the sound field was projected in front of the mist net compared with when the mist net was presented alone. This reduction in velocity would equate to a substantial reduction in the force of any collision. In addition to slowing down, birds increased the angle of attack of their body and tail, potentially allowing for more maneuverable flight. Concomitantly, the only cases where birds avoided the mist net occurred in the sound-augmented treatment. Interestingly, the sound field by itself did not demonstrably alter flight. Although our study was conducted in a limited setting, the alterations of flight associated with our sound field has implications for reducing bird-strike in nature and we encourage researchers to test our ideas in field trials.

Collisions between birds and aircraft cause billions of dollars of damages annually to civil, commercial, and military aviation. Yet technology to reduce bird strike is not generally effective, especially over longer time periods. Previous information from our lab indicated that filling an area with acoustic noise, which masks important communication channels for birds, can displace European Starlings (Sturnus vulgaris) from food sources. Here we deployed a spatially controlled noise (termed a “sonic net”), designed to overlap with the frequency range of bird vocalizations, at an airfield. By conducting point counts, we monitored the presence of birds for four weeks before deployment of
our sonic net, and for four weeks during deployment. We found an 82% reduction in bird presence in the sonic net area compared with change in the reference areas. This effect was as strong in the fourth week of exposure as in the first week. We also calculated the
potential costs avoided resulting from this exclusion. We propose that spatially controlled acoustic manipulations that mask auditory communication for birds may be an effective long term and fairly benign way of excluding problem birds from areas of socioeconomic importance, such as airfields, agricultural sites, and commercial properties.

This paper tackles a never-before-approached topic in Romania, as it aims to empirically analyse the 26 cases of collision between military aircrafts and birds that occurred between 1967 and 1991. The work is based exclusively on observations made by the Head of the Meteorological Department of the Romanian Military Aviation Commandment between 1990 and 1993, commander (retired) and meteorologist. This paper complements various scientific and statistical studies in the field, which lacked information about military aircraft bird strikes in Romania. In addition to these 26 collisions, 3 other incidents involving military aircrafts may have been bird-related. They occurred in 2002 (2, one of which was a catastrophe that lead to the pilot's death) and 2007 (1 incident). The study objectives were to analyse the collisions' locations (prevalence of certain aerodromes), the atmospheric and seasonal conditions in which the collisions occurred, and the types of aircrafts and bird species involved in the incidents, which resulted in a map of the analyses' main elements. In terms of results and conclusions, it was found that in Romania, in the analysed period, most of the collisions occurred in areas where aerodromes were located in the vicinity of water sources, in autumn, followed by spring, which is linked to the birds' migration activity, as well as to agricultural practices, as birds relocate in order to look for food sources. Most collisions occurred during the day, under normal meteorological conditions, up to altitudes of 400-500 m. It was also noticed that in over 50% of cases collisions occurred in the vicinity of aerodromes, most often during landing. The most important element that favours bird presence near aerodromes is food and water source availability, which is followed by the availability of various nesting-suitable locations. This study also touches on flight ornithological insurance, factors that stimulate bird concentration near aerodromes, recommendations for ensuring flight safety from an ornithological perspective, as well as methods used to hinder bird presence near aerodromes.