Simulation analysis of aerodrome CNS system reliability

Ensuring safety, regularity and continuity of air traffic are priority objectives of aeronautical regulations and procedures. They concern, among others, Air Traffic Control services (ATC), Communications, Navigation and Surveillance systems (CNS), Visual/Instrumental Flight Rules (VFR/IFR), minimal Meteorological Flight Conditions (FMC) and air traffic procedures. This paper focuses on aerodrome CNS systems reliability in relation to aerodrome traffic operations and ATC procedures. The aerodrome CNS system has complex technical and functional structure. The elements forming the system are very reliable and accurate. However, the possibility of their operational use depends not only on the technical state. Aerodrome ATC unit (TWR) can issue a clearance for performing an operation (approaching, landing, take-off and climbing) only when the requirements meet the actual conditions specified by FMC, ATC procedures and air traffic rules, approved Flight Plan and operational status of CNS devices. This means that different combinations of operational situations and reliability status of CNS devices should be considered. In this paper Petri nets are proposed to model the aerodrome CNS system reliability structure. The model was used to perform simulation analysis of CNS system reliability for different air traffic and meteorological conditions. Applicability of the method has been shown on the example for selected scheduling season.