Purpose: The article aims to show the viability of installing a precision-based approach system in Viseu airfield, in Portugal. This work looks to evidence to what extent the implementation of ILS (Instrument Landing System) or GBAS (Ground Based Augmentation System) in the airfield is viable, and which of the two would be the better option for this case, from a technical and economic view and as a way to increase safety levels.Design/methodology/approach: The article analyses the airfield’s evolution over time and forecasts its movements for the future, over a 10-year period, by utilising two different models: multiple linear regression and IATA traffic forecasts. The different types of airfield taxes were also reviewed and their values were estimated for the following years. The equipment’s technical aspects and individual prices were analysed to accurately determine the time needed for the airfield to recover the investment done, allied with an 80% funding European 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 very important, especially taking into consideration the safety they provide and other benefits that naturally come up with it.

In the present work is made an overview of the use of hydrogen in aviation, the modifications needed to convert a conventional gas turbine to use hydrogen and a CFD simulation of an existent gas turbine burning hydrogen. The CFD simulation was done in a CFM56-3 combustor burning Jet A (as a reference standard) and hydrogen, with the intention of evaluate the viability of conversion of existent gas turbines to hydrogen, in a combustion point of view, by analyzing the emissions through ICAO’s LTO cycle while burning this fuel. ANSYS Fluent 2020R2 was the software used to perform the numerical study. The RSM was the viscous model used. Only the NOx emissions were assessed as pollutant once the hydrogen combustion products are reduced to water vapor and NOx. These emissions were evaluated through a detailed mechanism and the NOx model available on ANSYS to get a better concordance with the ICAO’s values. During this study, several sensibility studies were carried out for hydrogen burn, for instance, the analysis of the air flow with/without swirl in the primary zone and different inlet pressure and temperature for fuel.