Infrastructure-focused assessment of airport operability under low-visibility conditions

Abstract

This paper aims to investigate the technical feasibility and infrastructure requirements for improving airport operability at Tuzla International Airport under low-visibility conditions. The study focuses on enhancing the performance of the existing instrument landing systems (ILS) CAT I system through targeted infrastructure improvements, including visual aids, lighting systems, runway markings and obstacle management, without upgrading the ILS category or introducing new navigational procedures. The analysis combines terrain and obstacle assessment using ICAO Annex 14 obstacle limitation surfaces and obstacle-free zone along final approach paths. Radar-based aircraft trajectory data were used to provide contextual insight into missed-approach performance. Selected surfaces associated with more demanding operational conditions were analyzed to identify terrain and obstacle constraints, while advanced analyses such as PANS-OPS and OAS remain outside the scope. Results indicate that, despite obstacle-related constraints limiting higher ILS categories, infrastructure upgrades can improve operational performance. Enhancements to lighting systems and visual aids increase the probability of establishing visual reference at decision height, thereby reducing disruptions. A simplified analytical model estimates an increase in operational availability of approximately 6%–8% annually without modifying operational minima. This study demonstrates that, where upgrading the ILS category is constrained by terrain, obstacles or economic limita-tions, infrastructure-based improvements can provide measurable gains in low-visibility operations within the existing ILS CAT I framework. By integrating obstacle assessment with a simplified analytical model, the study offers a practi-cal and cost-effective framework for improving airport operability without requiring complex navigation system up-grades.