The contents of the book "Ecological effects of drones"

Unmanned aerial vehicles (UAVs), are remotely piloted or autonomous aircraft that have (r)evolutionized various industries, including agriculture, transportation, delivery, construction and defense. They are increasingly used for tasks that are dangerous or too difficult for human pilots or where an alternative implementation would be too expensive. Also known colloquially as drones, UAVs offer many advantages: including high flexibility, mobility and, in certain use cases, cost efficiency. In recent years, advances in UAV technology have greatly expanded the capabilities of drones, increasing their potential for a wide range of applications.

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The concept of sustainability is defined very broadly in the literature. The concept of "sustainable development" was first defined comprehensively in 1987 in the Brundtland Report of the United Nations World Commission on Environment and Development. Sustainability is described as "development that meets the needs of the present without compromising the needs of future generations". The definition recognizes that sustainable progress takes equal account of the economy, the environment and social well-being. The term was subsequently adapted and expanded, although the original idea remained unchanged (Johnston et al. 2007).

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In contrast to other countries, environmental protection law in Germany is very complex. As there is no central environmental protection law in Germany that summarizes all applicable regulations, the general regulations and those specifically applicable to unmanned aviation are regulated in various laws and ordinances. Depending on the federal state, these regulations may differ from the federal laws. In addition to the LuftVg, the LuftVo and the EU Drone Regulation, the laws and regulations relating to environmental protection also apply to unmanned aviation. The new EU Drone Regulation has simplified the application of environmental laws and limited the responsibility of environmental protection authorities above a flight altitude of 100 m AGL. However, the interests worthy of protection must still be taken into account when flying over protected areas. Protected areas in Germany have different levels of protection. Overflight rules for unmanned aviation are classified according to these levels. Federal and state GIS portals can be used to determine the relevant protected areas in a flight area.

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Colloquially, the term "drones" has become established for unmanned aerial vehicles. Terms such as UAV ("unmanned aerial vehicle") for the unmanned aircraft or UAS ("unmanned aircraft system") for the entire system comprising the drone and peripherals, such as control units and software, have also become established. The main criterion of a UAS is that the aircraft is remotely controlled by the pilot. In recent years, drones have been developed in various designs with different flight characteristics. A specific design is not equally suitable for every application. Common designs and their main characteristics can be grouped together. The basic designs are the multicopter, the fixed-wing aircraft, the helicopter and the VTOL gyrocopter. The analysis shows that the fixed-wing aircraft is the most suitable design for medical logistics over medium and long distances due to its economical forward flight. Ecological aspects such as energy efficiency and noise emissions are also taken into account when evaluating the designs.

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The development of innovative unmanned aerial systems has accelerated considerably in the last five years in particular. An assessment of the individual developments according to their significance or their impact on the environment is only possible to a limited extent due to their complexity. Even though increasing the safety and reliability of the systems is currently being prioritized, developments with a focus on environmental protection are becoming increasingly important. This is not just about applications in which drones are used to detect or eliminate environmental hazards; the development of more energy-efficient systems and aircraft with lower noise emissions, for example, are also key areas of development work. Not only are materials and drive concepts being put to the test, but artificial intelligence is also being used to optimize decision-making processes in flight preparation and execution. The development and implementation of so-called U-Spaces is currently a controversial topic. The U-Space concept is intended by legislators to reorganize flight operations, especially for drones, in the lower, previously uncontrolled "Gulf" airspace and thus increase the safety of all aircraft moving in this airspace. Private operators are to be licensed for this air traffic control, who are to charge fees to finance the service. Irrespective of the economic uncertainties resulting from this financing method, the level of digitalization required by the regulator EASA in U-Space is extremely high. Considering the complexity, it is therefore to be feared that the implementation of the envisaged U-Space Act could fail simply because of the complex systems still to be developed. The U-Space provider requires considerable capital for the development of a system, licensing and the pre-financing of ongoing operations. This means that a takeover of the service will probably only be possible for investors or large corporations. The risk of monopolization should therefore not be underestimated. However, regardless of the financing and complexity, a U-Space could certainly make sense for environmental protection, if the rules it establishes mean that environmental and animal protection can be enforced more flexibly depending on the season and situation.

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One of the biggest challenges in unmanned aviation is energy management. The right choice of drive and energy storage system is crucial for the possible range, payload and ultimately the economic efficiency. With the aim of implementing an environmentally friendly means of transportation, drive concepts based on fossil fuels must be replaced by sustainable solutions. The lithium-ion batteries and hydrogen currently being discussed as energy storage systems are being investigated for their suitability as energy storage systems in unmanned aviation. When considering the ecological footprint, it is determined that, taking into account the upstream chain processes and the possibility of recycling, neither energy source can be produced and used in a completely CO2e-neutral manner. Even if the high gravimetric energy density of hydrogen makes it appear interesting as an energy source, it is above all the framework conditions, such as energy-intensive production, difficult handling, lossy transport and storage, that speak against the use of hydrogen in general in mobility and especially in unmanned aviation. It can be assumed that the lithium-ion batteries that are currently primarily used will continue to be the most effective energy source for electrically powered drones for some time to come. Increasingly, we are seeing trials with hybrid drives in which the primary battery is permanently recharged during flight by an on-board generator. This generator could, for example, convert green liquid fuel with a higher energy density into charging current and thus increase the range of the aircraft.

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In medical logistics, substances classified as hazardous substances are transported in accordance with the BioStoffV. The transportation of hazardous substances in an unmanned aircraft is generally subject to approval. The transportation of hazardous substances is also associated with special packaging and handling requirements. In the field of drone logistics, studies and practical trials have shown that the conventional packaging solutions used on the ground cannot reliably prevent the release of the transported goods due to the forces acting on the aircraft in the event of a potential crash. Due to the limited transport volume available in a drone, the weight that can be carried and the potential impact of force, the packaging must be adapted to the aircraft. This requires reinforced film bags. The transport packaging can be considered highly effective in terms of its protective effect, but the materials used are ecologically questionable. The desired quality of the films used for the packaging prevents the use of recycled materials and also makes reuse after use more difficult.

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As part of official approval procedures for drone flights beyond visual range, noise emissions and shadowing in particular are considered with regard to their environmental compatibility.

EASA has submitted a proposal for a directive to determine noise emissions which, on closer inspection, is rather difficult to implement in practice. The proposed measurement methods can only be implemented in practice with great effort and the results obtained are difficult to interpret and classify. The results obtained must therefore be assessed as rather irrelevant in practice. A permanent measurement at the source, i.e. on the aircraft itself, is proposed as an alternative to improve relevance. This not only makes it easier to record the data, but also to analyze interactions with flight operations, weather conditions and, for example, system states of the aircraft. When measuring the noise emissions of a fixed-wing aircraft, it was no longer possible to separate the noise emitted by the drone from the general noise pollution. A measurement method from Austro Control, which is no longer valid but easy to implement, was used. The test took place at a model airfield in a rural area north of Berlin.

The disruptive effect of shadows cast by an aircraft on wildlife living on the ground has so far been investigated primarily on the basis of mental models. In order to obtain more realistic results, the shadow cast by a fixed-wing aircraft in an ideal environment is simulated in the 3D software "Blender". At the usual flight altitude of over 100 m AGL, no shadowing could be determined in the simulation carried out on a real scale.

The available investigations allow the conclusion that noise emissions and shadowing are not relevant disturbance variables in normal flight of a fixed-wing aircraft.

Further studies focus on the impact of drone flights on birds on the ground and in the air. The evaluation of existing studies has shown that none of the flight patterns used are comparable with the flight patterns used in medical logistics. However, according to the assessment and experience of drone pilots, damage to birdlife is rather low or unlikely if flight planning is carried out with foresight. When analyzing the potential for disturbance to birds, findings from the training of hunting falcons are also taken into account.

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In Germany and especially in some Eastern European countries, African swine fever (ASF) poses a serious threat to the keeping of pigs for breeding and production and to agriculture as a whole. The disease spreads extremely quickly, particularly through wild boar. As part of the fight against African swine fever, the use of drones with thermal imaging cameras has proven its worth in the search for wild boars and wild boar. The average flight altitude of 100 m AGL chosen for the search and the "lawnmower flight pattern" usually used are comparable to flights in medical logistics. In order to investigate the effect on animals living on the ground, 667 flights carried out as part of the ASF control were evaluated. The observations did not focus on specific behavioral reactions of the animals. The result is that no changes in movement, acceleration or flight behavior could be detected during the search, regardless of the animal species observed. There were also no incidents of collisions, attacks, mock attacks or flight behavior by birds during the entire observation period. All the animals observed behaved in such a way that it can be assumed that the drone does not emit any visual or acoustic signals that are perceived as disturbing by animals.

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Effective environmental protection begins with flight route planning. In the recent past, environmental protection authorities have intervened considerably in flight planning and flight safety by imposing conditions. Due to the lack of experience with drone technology, particularly in the environmental authorities, and often inaccurate theoretical assumptions, conditions could also have a negative impact on the environmental compatibility of drone flights. In some cases, not only were environmental standards lowered, but potentially environmentally friendly drone flights had to be replaced by ground-based transportation that was more harmful to the environment.

The conditions imposed by environmental authorities are critically analyzed. Technical limitations of drone technologies, but also incorrectly applied study results are pointed out and practical environmental protection measures are proposed. As a result of the investigations, it can be concluded that forward-looking flight planning is the most effective method of protecting the environment and wildlife.

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Protecting the environment is a very high priority and a social consensus. The way in which it should be implemented in practice, on the other hand, is often disputed. The primary aim of this publication was to present the complex interrelationships in drone logistics in order to provide a technical basis for communication between applicants for approval of drone flights beyond visual line of sight and the authorities involved in the approval process and thus improve it. The focus here was on illustrating the impact of drone flights in medical logistics on flora and fauna in particular, as well as on the factors that significantly determine the ecological footprint and ways in which this footprint can be actively reduced.

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