Are remote towers safer than conventional towers?

HungaroControl2021. 02. 22.

Zoltan Molnar – HungaroControl

Although the implementation of remote tower technology represents a complex change, which significantly affects the ATM functional system, the safety assessment process does not require any specific methodology. In other words, it can be managed as a normal change process, despite it is still remaining a difficult task. Air Navigation Service Providers (ANSP) should follow local regulations and procedures defined by their own Safety Management System, while ICAO documents (such as Doc 4444) should also be taken into consideration. As the industry has gathered more experience with this new technology, the main issues and benefits of remote towers have been identified, and several useful guidance documents have become available, such as those published by EASA (ED 2019/004/R Annex I – GM on remote aerodrome air traffic services) and CANSO (CANSO Guidance Material for Remote and Digital Towers). Available standards and guidance materials also support competent authority oversight, which remains a key factor for any successful remote tower project.

From an operational point of view, the key difference in a remote tower compared to a conventional tower is the visual surveillance system. Risks concerning this new technical system might arise in different levels. Regardless of the size of the airport, identification of visual needs of controllers are critical. Camera system design including locations, orientation, types and quantities should be based on these needs. Visual presentation (panorama or videowall views) and personal screens should be designed carefully to provide the necessary view and image quality. To mitigate these new risks, proper definition and a safe design based on risk assessments, including special attention to software safety aspects is inevitable. 3D simulation can be a useful tool to pre-validate camera locations and visual presentation, as well as involving end-users into the design process as soon as possible.

Since a remote tower centre is typically implemented in a different location – which can be within the airport or hundreds of kilometres away – additional interfaces, network elements are added to the current system, and these might affect the operational procedures. Interaction and potential integration with the existing systems should be assessed carefully. Last but not least, human factor issues are also critical. The effect of the new systems for controller workload and situational awareness should be assessed. Their involvement in the design and implementation processes is very important to build confidence and trust towards the new solution.

Although remote tower operations might add extra risks, a well-designed system has numerous safety benefits, which can increase the overall safety level of the functional system. The location of conventional towers in the aerodromes is a given, and as the size of airport facilities grow, the distances from the tower increases, undermining the effectiveness of visual observation. A well-designed visual surveillance system can solve this problem, and gives a more complete view even from the furthest points of the aerodrome, thereby increasing situational awareness. The system is more flexible, making further expansions and adjustments easily feasible. Filtering functions can enhance image quality and provide better visualisation even in low visibility periods, and the possible integration of the visual surveillance  system with other systems (such as A-SMGCS or MET system) enables adding extra information on the video wall (or panorama) and CWP screens (e.g. labelling function). Image recognition algorithms can support additional functions, for example safety nets in the system.

Even though issues and benefits are more or less general, two absolutely similar remote tower solutions do not exist. Local operational and environmental aspects always have to be taken into consideration. Proper safety assessment and validation processes must be conducted to minimize the effects of new risks and maximize safety benefits of this new technology. So the answer to the question in the title is a definite yes: with mindful design, relying on the experience of those who are already operating a remote tower and with paying attention to every detail, a digital tower can be even safer, than a conventional tower.

About the author:

Zoltan Molnar is an accomplished safety and risk management expert at HungaroControl. He is responsible for the safety assessment of HungaroControl’s remote tower program in Budapest, and he is also plays a pivotal role in remote tower related consultancy and R&D activities. He is active in other ATM projects, like cross-border free route airspace implementation, and participates in ATM safety monitoring activities, and  AI safety working groups.