## 2 Related Works
The role of redundancy and maintenance in secure communication systems is critical, as explored in [13]. This paper explores the enhancement of communication channel reliability in ATC systems, which are crucial for flight safety. It focuses on the effectiveness of using redundancy with a common set of standby radio stations, combined with periodic maintenance, to improve communication between air traffic controllers and pilots. The origins and applications of the RED/BLACK concept have not been extensively discussed in the literature. Both the concept itself and the equipment that implements it are reflected mainly only in information from manufacturers of such equipment. The voice communication systems include important features to cope with the specific needs of advanced and secure communications on the basis of the RED/BLACK concept, which are described in [14]. Red/Black Web-Based HF Radio system monitoring is described in [15]. In [16] the RED/BLACK multi-level security architecture for secure and non-secure communications is given. L3 Harris has developed a digital inter-communication system (ICS) that provides operators with intuitive and flexible access to mission audio. The ICS-based platforms can use their red/black separation features for simultaneous and secure audio [17]. The VOICE C2 Red/Black [18] is a system, tailored for secure, multi-enclave operations in fixed and deployable air defense settings. The system allows simultaneous access to both secure (RED) and non-secure (BLACK) communication channels, integrating operator positions, communication equipment, and a cross-domain solution for unified control of both asset types from a single console. The R&S(r)M4 ACS is a state-of-the-art, fully IP-based voice communications system designed for seamless airspace operations, combining rich functionality with exceptional usability [19]. Using the benefits of IP technology, it offers robust security, resilience, and supports crypto pooling. It enables operators to manage all communications from a single screen while maintaining strict security. The system distinctly separates secure (RED) and unsecure (BLACK) domains, allowing simultaneous access to both using the same audio accessories. AviCom is an advanced radio and audio management system designed to give aircraft crews complete control over communication assets, ensuring secure audio management [20]. It digitally processes audio, classifying it as secure (RED) or non-secure (BLACK), with hardware-level interlocks guaranteeing the protection of secure communications. This system is adaptable for various RED security levels, making it suitable for clients with complex rational and international security needs on a unified platform. Orion's RED/BLACK switch facilitates a seamless shift from unsecured to highly secure communications, integrating with radio encryption terminals [21]. This device enables the placement of encryption mechanisms in a secure zone, distinct from radio equipment, accommodating operational scenarios that require the separation of encrypted digital radio packets and secure voice calls. Radio communications reliability issues are one of the key components of the air traffic control system. The paper [22] discusses the advent of cognitive radio technology, highlighting its prospects for enhancing spectrum efficiency in civil aviation by enabling dynamic spectrum access. It delves into the current research, regulatory landscapes, and the challenges hindering its adoption in aviation. The paper [23] examines how advancements in power electronics and energy processing can potentially disrupt onboard aircraft equipment and ground stations that provide air traffic services, with a specific focus on emergency radio systems. It details experimental efforts to measure the effects of high-power electronic interference on emergency radio systems, highlighting the significant risks posed to aircraft backup systems and very high-frequency radios.