A comparative study between ILS and GBAS approaches: The case of Viseu airfield

Abstract

Purpose: The article aims to show a comparative study between two precision approach systems and check the viability of installing one of them in a specific regional airfield, using Viseu airfield, in Portugal, as a case study. This work looks to evidence to what extent the implementation of ILS (Instrument Landing System) or GBAS (Ground Based Augmentation System) in these types of airfields is viable, and how to choose between them for this case, from a technical and economic view and as a way to increase safety levels. Design/methodology: The article analyses the airfield’s evolution over time and forecasts its movements for the future, over a 6-year period, by utilising IATA traffic forecast models. The different types of airfield taxes were reviewed and their values were estimated for the following years. The equipment’s technical aspects and individual prices were compared and analysed to accurately determine the time needed for the airfield to recover the investment done, allied with 80% funding from a European investment project. Findings: Approach systems are being modernized, and throughout the years more airports and airfields are starting to replace old approach systems for satellite-based new ones. When compared to ILS, GBAS offers more advantages at a technical and economic level, and even for smaller airfields with a low traffic volume, sometimes it can be technically and economically possible to have such systems implemented. Originality/value: Studies about the implementation of new radio aids are usually prepared for big airports by airport operators or ANSPs before major investment projects. However, for most small regional airports in the country, where traffic is not near as big, such studies don’t exist, and for that reason, investigating the possibility of installing such kind of equipment is