6.8 Remote tower system constituents

In relation to the demonstration of compliance with the applicable articles of and annexes to Regulation (EU) 2018/1139 [1], the split of the technical system into constituents falls under the responsibility of the ATM/ANS service provider, in agreement with the respective competent authority. The split may depend on several factors, such as the availability of community specifications for certain parts of the system and even how the contractual arrangements between the service provider and the constituent manufacturers are established. Based on the considerations above, some recommendations are put forward on how the remote aerodrome ATS system may be split into constituents. Based on the high-level remote aerodrome ATS functionalities presented in Chapter 5, the remote tower system constituents may be grouped as follows: Visual-presentation-, binocular-functionality- and aerodrome-sound-related functionalities; voice/data-communication-related functionalities (i.e. aeronautical mobile service, aeronautical fixed service and surface movement control service); manoeuvring- and monitoring-related functionalities (e.g. signal light gun, management of aerodrome equipment/systems such as aeronautical ground lights and navigation aids, alarm management, technical supervision). The aforementioned functional grouping has been selected as the basis for the proposed split, identifying a constituent as responsible for the implementation of each of these categories. Nevertheless, these recommendations are based on two main assumptions that: the system (physical) architecture ensures independence of each of the constituents; and the interface specification among them is based on existing standards. For a particular technical solution, the validity of these assumptions should be assessed by the ATS provider. It is also important to analyse the ATM/ANS service for which a constituent should be considered, as this may also affect the possible split of the system into constituents. The main question would be whether the visual surveillance system and aerodrome sound are to be considered as constituents in the ATS domain or as a combination of ATS constituents and CNS (surveillance) constituents, or, in other words, if the visualisation means (cameras) and aerodrome sound means (microphones) can be considered as ATS surveillance equipment. With regard to that, the definition of ‘ATS surveillance system’ of Regulation (EU) 2017/373 [4] is recalled: ‘ATS surveillance system’ means a generic term meaning variously, ADS-B, PSR, SSR or any comparable ground-based system that enables the identification of aircraft. GM1 141.ATS states: ‘A comparable ground-based system is one that has been demonstrated, by comparative assessment or other methodology, to have a level of safety and performance equal to or better than monopulse SSR.’ The image captured by the cameras/optical sensors is used to replace the ‘out-of-the-window view’ with a ‘visual presentation’ and to replace the use of a traditional binocular with a ‘binocular functionality’. It is not intended for provision of ATS surveillance services, nor does it provide the necessary means and information for that purpose. (For instance, the precise distance between two aircraft in flight cannot be provided.) It is to be used primarily for the ‘detection’ and ‘recognition’ of aircraft (as well as for other objects and purposes, e.g. vehicles, personnel, obstructions, animals, occurrences at the aerodrome, weather follow up, etc.) and normally not used for the ‘identification’ of aircraft for the purpose of ATS surveillance services provision. The aerodrome surrounding sound captured by the microphones is used as a means to increase the general ATCO/AFISO situational awareness, but is not used for the ‘identification’ of aircraft for the purpose of ATS surveillance services provision. Following this analysis, it has been concluded that the ground infrastructure at the aerodrome for capturing images and surrounding sound should be considered as ATS constituents (or part of ANS constituents). The following table summarises the results of both analyses that constitute the recommended way of organising the allocation of the system’s constituents. Table 1: Remote tower system constituents

The following is noted: EUROCAE has published ED-240A Change 1 [19], a Minimum Aviation System Performance Standard (MASPS) for Remote Tower Optical Systems. The denominations of the constituents are included for illustrative purposes only. The ATS provider may split further these constituents (e.g. splitting between equipment at the aerodrome and at the remote tower/RTC), which would require the definition of the interface specifications (standards) among the identified new constituents. The ATS provider may consider the possibility of including additional constituents or additional functionalities to the identified ones. The ATS provider may consider adding other functions to the identified constituents, provided that they are consistent with the ATM/ANS service (ATS or CNS) provided. The ATS provider may consider merging visual surveillance system, aerodrome sound reproduction and manoeuvring and monitoring, as they belong to the same domain.