Eva Santos has been working for SENASA for more than eleven years as Aeronautical Noise and Environment Expert, mainly supporting the Spanish Aviation Safety Agency (AESA). Her professional career has been linked to the acoustic and the environmental noise fro more than 18 years, after pursuing studies on Technical Engineering of Telecomunications, along with a Master on Environment and Energy Management. Eva tells us how concerns have evolved regarding environmental issues in the aviation sector, specifically related to noise, and how SENASA plans to address future challenges.

What distinctive features describe noise in the aviation sector?

One of the characteristics of environmental noise, as is the case with other branches of the environment, is that it is transversally linked to the different actors involved in air transport and, at the same time, to external actors. In other words, it is not enough to address the problem from the point of view of airports and their operation, because air navigation, aircraft, airlines, authorities, aeronautical legislators, among others, are also involved. It also depends on a correct urban development and an adequate regulatory framework in time and form so that environmental regulations are compatible with aeronautical regulations, and vice versa. And in this sense, communication with citizens, with other administrations, transparency in management and information also play an important role. A very broad and multidisciplinary vision on noise is necessary, so it is essential to help the aviation authority to consider all sides of the noise problem, because the solution is not always exclusively aeronautical.

From my previous experience in other fields of environmental acoustics, in sectors other than aeronautics, I have learned over the years that the annoyance of aviation noise adds a very important factor to this issue that is not directly related to the noise levels or decibels produced. The perception of noise nuisance from transportation in general, and from commercial aviation and airports in particular, by citizens is influenced by non-acoustic factors. For example, we talk about social and economic conditions, age, education, type of housing, or access to information. All this affects how and how much noise disturbs, but specifically in the case of aeronautical noise there is a greater sensitivity among the population.

The latest reports of the World Health Organization (WHO) attest to this fact: for the same noise levels in the different means of transport, aircraft noise is the most annoying and sleep disturbing. There are several reasons for this, but an important reason is that for those affected, aeronautical noise “seems” to have no solution, since an air route cannot be screened, like a road or a railroad track. Therefore, when someone knows that he or she has or will have an airway nearby, he or she automatically believes that it will be a problem forever, with no solution, although perhaps after measurements, it may turn out that the noise is less than that produced by a nearby road. Noise experts believe that it is a problem due to annoyance perception, as solutions exist and are applied whenever possible.

What are those solutions to mitigate the effects of noise that we can provide from our experience?

Aircraft are evolving and becoming quieter, routes are also being adapted to be more precise and this reduces the dispersion of aircraft. It is also possible to force certain altitudes on takeoffs and landings, the so-called CDOs or CDAs, to fly over populations at a higher altitude. In other words, there are possible strategies and solutions. Where perhaps we need to insist is in managing fluid and accessible communication with citizens and local administrations to inform them of the efforts made by the sector.

In addition to this scenario, there is a growing damage to the image of air transport due to its influence on climate change, although reality shows that this effect is very low compared to other means of transport or other sectors. All these perceptions negatively affect the environment image and reputation of commercial air transport and airports, completely ignoring the benefits its has provided and intends to continue to provide to society and development.

The international regulatory body, ICAO, established years ago the four basic pillars on which to act for noise management at airports. These are, first, to reduce noise at the source, second, to act in the territory, third, to implement operational noise reduction measures and, finally, when the other measures fail to achieve the objectives set, to apply operational restrictions at the airport. This strategy for airport noise management is known as the “Balanced Approach”.

European Union has implemented a regulation, mandatory for all member countries, to rule how to manage noise at airports with more than 50,000 movements per year and, in addition, it has linked it to the environmental directive, in order to establish the way to make noise assessments through noise maps and from there take the most appropriate decisions. What is new in all of this is that environmental regulations are shifting to the assessment not only of noise, but also of annoyance. Therefore, pure compliance with the noise levels established by the regulations will no longer be sufficient for proper noise management. Action should be taken where annoyance can be avoided, and consideration should be given to how each of these social, psychological, and environmental factors that influence noise perception may affect it.

What has SENASA done so far in the field of environmental noise?

The functions within the assignment linked to AESA have evolved over time. One of the starting points was the assistance in the first AESA sanctioning proceedings against airlines for deviating from the routes established in Madrid. These routes were designed to avoid overflight and noise from certain populations so that, if the aircraft did not stay within the tolerances of the flight maneuvers, overflights occurred and therefore the nuisances and problems with the environment. As a result of the two major airport expansions (in Madrid and Barcelona) almost two decades ago, several legal proceedings were initiated in which the Ministry of Public Works (now the Ministry of Transport, Mobility and Urban Agenda) needed specialized assistance in noise and airport issues, both technical and legal. SENASA provided this assistance with very positive results. Throughout these years we have also actively participated in the revision and development of regulatory texts and procedures and guidance material for AESA. It is worth mentioning SENASA’s support in the analysis of noise studies within the Environmental Impact Assessment procedures for aerodromes and heliports, in which AESA is the substantive body, i.e., AESA is the responsible for their authorization and environmental procedures.

In addition to these activities, training activities on aeronautical noise and airport noise have been carried out continuously, not only for civil aviation authorities (DGAC and AESA), but also for air navigation providers, flight procedure designers, controllers, legal specialists, and international authorities. Through this SENASA became a reference center, almost exclusive, for this type of courses, with very complete programs that cover various disciplines. Training, in a way, is also awareness-raising; it is another point that must be emphasized in order to tackle the problem.

Al margen de estas actividades se han llevado a cabo acciones formativas sobre ruido aeronáutico y ruido de aeropuertos de manera continua, no sólo para las autoridades de aviación civil (DGAC y AESA), también para proveedores de navegación aérea, diseñadores de procedimientos de vuelo, controladores o especialistas jurídicos o autoridades internacionales. Esto ha hecho que SENASA sea un centro de referencia, casi exclusivo, para este tipo de cursos, con programas muy completos que contemplan diversas disciplinas. La formación, en cierto modo, es también concienciación, es otro punto sobre el que se debe incidir para atajar el problema. Cuantas más partes conozcan cómo se genera y propaga el ruido, cómo se evalúa a través de mapas y de mediciones, y cómo pueden influir las distintas actividades aeronáuticas en la molestia, más cerca estaremos de minimizar el problema.

International training also offers a different and enriching perspective. We have had several experiences, some of them very special, such as the integration program we carried out with the Ukrainian Aviation Authorities, within the framework of the European Twinning project, long before the conflict with Russia started and even before the Maidan riots. Precisely, the Twinning program, in which SENASA also participated together with the AESA, sought to harmonize the regulations of certain non-EU countries with those existing in Europe. Ukraine was on the path to converge its regulations with those of the European Union, with a view to joining the Union sooner or later. More than a training activity, it was an exchange of knowledge and a great challenge, since it was necessary to condense in a few months what had been developed in Europe over the last twenty years in terms of noise and environment. It involved a great deal of reflection and exchange of experience in order to align two disparate scenarios with totally different urban, territorial and environmental competencies and regulations. I am sure that all effort made at the time will pay off, sooner or later.

What are the next challenges for SENASA in terms of aeronautical noise?

We are now at a time of important regulatory changes, which are a boost to the environmental noise tasks on airports that are carried out with AESA. On the one hand, we have a recent Royal Decree by which AESA begins to approve civil flight procedures and airspace changes, i.e., takeoff maneuvers, approaches, routes, among other changes proposed by civil air navigation service providers. This implies that the designs of new maneuvers, or the modification of the existing ones, as part of their approval procedure, must go through an environmental procedure, in accordance with the Environmental Evaluation Law.

Noise is a determining factor in this environmental analysis. SENASA has collaborated in the definition of the analysis criteria to assess the possible impact depending on the projects to be approved. We are in a phase of initiation of the first procedures that fall within the scope of this new regulation, and which will involve the implementation of the first evaluations of these projects.

On the other hand, it is expected that in the near future a redefinition of airport noise monitoring competencies will be established, and a Competent Authority will be assigned for operating restrictions and the application of ICAO’s “Balance Approach”. This is an important milestone that will require the assistance of a team of experts and will allow us to participate in an exciting project supporting the authority’s tasks.

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