The digital era of Remote Control Towers

Remote control towers have become a reality in air traffic management. The next step is already being examined: multiple remote towers, from which more airports can be controlled simultaneously. Experimentation has begun, and multimodal aspects in virtual environments play a key role.


Air traffic in European skies is increasing. In 2017, 10 million aircraft have circulated in Europe, carrying 1.6 billion passengers. These are significant numbers already, which will grow further by 2030, when flights will amount to 16.9 million a year. The European Union intends to tackle the incoming increase in air traffic, while continuing to ensure the highest standards of safety and minimizing delays and cancellations of flights. For this reasons, it has established SESAR – the programme for the study, management and modernization of European airspace – and invested 1.5 billion euro.

However,  it will not be an easy challenge for the Air Traffic Management (ATM) system. First of all, the entire ATM system will have to be updated with innovative technologies and new operating procedures. In addition, transformations will inevitably also involve human and organisational aspects, closely linked to technological aspects.

Transitioning to digital

A major step towards a more efficient and modern Air Traffic Control (ATC) system has already been taken with the introduction of Remote Control Towers. They are based on an air traffic digitization system, by which a sophisticated set of panoramic cameras and high-definition microphones communicate wirelessly with a remote hub, a room where dedicated monitors transmit to controllers all the information necessary for ATC. The first of these towers came into operation at the Örnsköldsvik airport in Sweden in 2015, after a year of experimentation. Experimentation in airports with higher traffic density followed the remote management of small airports.

In Italy, ENAV, the company managing civil air traffic, took the first step. ENAV was part of the RACOON (Remote Airport Concept Of OperatioN) project in the SESAR Framework, established at a control room of the Malpensa Tower in Milan. RACOON managed from the Malpensa tower more than 100 movements, between take-offs and landings, at Linate airport. Therefore, the control tower of the first airport performed the functions of the second one, despite being 60 kilometres apart. According to Michela Terenzi, R&D Manager and Human Factors expert at Deep Blue, in charge of human performance assessment for RACOON:

Remote tower operations have not had a negative impact on controller performance in traffic management and have not required significant changes in conventional working methods”.

Malpensa was the world’s first experiment in remote management of a high traffic density airport. Iacopo Prissinotti, director of ENAV’s international activities, stressed that these were “real flights”, although the controllers in Linate were ready to intervene in case of need.

Single remote towers are now active in several European and US airports. The ATM sector, however, is already looking to the next major challenge: the Multiple Remote Towers.

Centralising Air Traffic Control

Addressing the increase in air traffic in the coming years, and ensuring high levels of safety and efficiency of control towers, while at the same time reducing costs. How? With Multiple Remote Towers (MRT), hubs equipped with technologies enabling air traffic management of multiple airports remotely and simultaneously. Initially conceived as an easy and economical solution, but only suitable for small airports and low density traffic, the technology is now being tested also for ATM of large airports.

The concept of a Multiple Remote Tower was first tested in November 2017 at the DLR Air Traffic Validation Centre in Braunschweig, Germany. There, a single remote tower oversaw more than 30 operations per hour from Hungarian airports in Budapest, Pápa and Debrecen.

The Remote Tower for Multiple Airports

Testing continued in March 2018 with two parallel testing sessions. HungaroControl, Frequentis AG, DLR and Selex ES GmbH (Leonardo LTD) composed the consortium of the “Remote Tower for Multiple Airports” project, part of the SESAR 2020 programme. The project performed the first session in Germany. There, air traffic controllers (ATCOs) managed 22 different scenarios with the help of different support functions. During the 50-minute validation sessions, experts were able to assess the safety levels, workloads and overall performance of the ATCOs involved.

The second session was carried out in Norway. The technology company INDRA used 3D to recreate the environment of the towers at the Norwegian airports of Røst, Haugesund and Bodø. Also, the test involved Avinor, a Norwegian provider of air navigation services. During the simulation, three experienced ATCOs worked on three different scenarios with increasing traffic and complexity. After the exercises, interviewers assessed aspects such as situational awareness, perceived workload, operational limitations, feasibility and tools to achieve greater analytical capacity. This test provided valuable information and results. Most of all, it demonstrated the ability to manage multiple airports simultaneously, providing a solid basis for the developments envisaged by the project. SESAR’s parallel tests are a first step towards simultaneous remote management, from a single control point, of the traffic of several airports.

The Italian experience

The challenge was also taken up in Italy by ENAV with its new industrial plan for the period 2018-2022. ENAV currently manages national air traffic from 4 control centres (Rome, Milan, Padua and Brindisi), which assist aircraft during the en route phase. In addition, 45 control towers in as many airports manage take-offs, landings and ground handling of aircraft. Finally, some control towers generally carry out approach in the phases of ascent and descent for smaller airports. Some of the control centres do so only for the major national ones.

With an investment of 650 million euro over 5 years, ENAV plans to consolidate the Rome and Milan control centres. This will allow them to take over the activities of almost all the approach centres located in the control towers. A real technological revolution will also take place in the airports of Brindisi and Padua. These two hubs will gradually manage remotely the control towers and the main activities of other airports.

Claudio Biagiola, head of the Malpensa control tower for ENAV, highligts that “Nothing can replace the human factor, which is fundamental for ATC”. For sure, ENAV will invest in developing and implementing new technological platforms. Part of the investments, however, will go to the training and education of its personnel. Also, ENAV will need to modernise some infrastructures in preparation for the transition to the new operating model. Once fully operational, this will also allow the centralisation of monitoring and maintenance activities. Therefore, this will bring a sharp reduction in costs and intervention times and an increase in productivity.

MOTO and multimodal stimuli

With the transition to the new ATM model, part of the work of air traffic controllers will also change. ATCOs will have to adapt to the new remote working scenario, to the new technologies and skills these require, and to different workloads. In parallel with the technological implementations, it is therefore essential to study the impact these will have on human work. Humans, in fact, will continue to be fundamental and irreplaceable.

So far, the progress of human performance in air traffic management from towers has focused primarily on one sense: sight. Hence, there is still an unexplored potential, linked to the use of other perceptual senses. Therefore, improvement in the performance of air traffic controllers operating in remote towers is possible. This new field of research includes the European project MOTO (Multimodal Remote Tower in Virtual Reality Environment), financed as part of the SESAR programme, coordinated by Deep Blue.

The project started in June 2016 and lasted 24 months. It identified the main multimodal (and multisensory) stimuli that remote control towers require to improve the “sense of presence” experienced by ATCOs. Improving stimuli beyond sight contributes to creating a greater sense of awareness and reality for ATCOs working in virtual environments. This deceives the brain, making it believe it is actually, physically in the control tower. Multisensory stimuli increase this sense of presence, consequently increasing the performance of air traffic controllers.

Validating MOTO

The first validation experiment involved 15 controllers. They worked in a virtual reality environment using the HTC Vive Head Mounted Display platform. ATCOs were asked to manage different realistic scenarios of operations with different, gradually increasing levels of complexity. The activity was carried out in four conditions of sensory mode: only visual; visual and auditory; visual and tactile; and visual, auditory and tactile. Neuroscientists led by Prof. Fabio Babiloni of La Sapienza University in Rome developed a set of neurophysiological signals and indicators (electroencephalography, electrocardiography, galvanic skin response and electrooculography). Using these indicators, the validation investigated the performance, sense of presence, ability to maintain full awareness of all relevant aspects, and the cognitive workload of the ATCOs participating in the experiment. Experts then completed the validation administering a subjective questionnaire.

The first phase of validation of MOTO was positive. It demonstrated that activating a pair of stimuli (visual and auditory, or visual and vibrotactile) supports air traffic controllers. Specifically, it favours their performance, reduces their workload and increases their sense of reality and presence. On the contrary, if multimodal feedback is given to all three areas at the same time, performance is reduced. This is probably due to an overload of stimuli, which are difficult for the brain to process.

The experimentation of MOTO continued to a second phase. It moved from a virtual to a more realistic context, at the ENAC remote control tower platform in Toulouse, France. This platform integrated many prototypes developed in MOTO, with the aim of amplifying the multimodal feedback provided to the controllers. These prototypes provided one sensory stimulus at a time or two at most. The results of this second experimental phase allowed to draw a first course for the next studies on multimodal supports to be inserted in the remote towers.

Advantages for the Air Traffic Management sector

MOTO studies on remote multimodal towers in virtual reality environments could significantly benefit the digitization of the ATM system. Also, they will be equally useful for the development of multiple towers.

In addition, MOTO made available a cheap and flexible tool, the virtual reality platform, used in its validation tests. The tool is adjustable to different scenarios, and allows to test new concepts and to perform training and validation. An important moment of exchange on remote control towers took place during the International Symposium Remote Tower 2018 in Toulouse. The event aimed at all potential actors of air traffic control (from research to industry). It was also an opportunity for MOTO to share its experiences and progress on the digitization of control towers.

Vera Ferraiuolo

Senior Dissemination Consultant