A four-hour flight from Europe, the Cape Verde archipelago offers visitors mountainous volcanic landscapes, golden beaches, marine wildlife sanctuaries and its rich crioula (creole) a blend of its Portuguese past and African roots. The dry, warm climate means that the attractions of these Atlantic islands that together form Africa’s most westerly country can be enjoyed all year round. In 2019, Cape Verde welcomed 758,000 tourists with its traditional morabeza (a creole term meaning hospitality, friendliness), a figure that has steadily increased over the past two decades from 28,000 visitors in 1995, and has established itself as a destination for sustainable and nature-based tourism.

To meet this growing demand, several years ago the country began to expand and modernise its airports. Ineco first started working in the archipelago in 2003 and since then has continued to provide services to the national company Aeroportos e Segurança Aérea, ASA (see ITRANSPORTE 50 and 61). Currently, the network consists of four international airports –Sal, Praia, São Vicente and Boavista– and three airports for domestic traffic, São Nicolau, Maio and Fogo. For the São Filipe aerodrome, Ineco is carrying out a study of flight procedures for the implementation of night operations.

In early March 2021, it also presented the technical feasibility study prepared for ASA on a new international airport on the island of Santo Antão, at an event held in the capital, Porto Novo, attended by the country’s top officials.

The fifth international airport, in Santo Antão

In total, the Cape Verdean territory, with just over 530,000 inhabitants, is made up of 15 islands and islets: 10 large ones (one of which, Santa Luzia, is uninhabited) and five smaller ones. All of them have at least one seaport and ferry lines, which together with domestic flights provide internal mobility. International airports are the main gateway for foreign tourism, which in 2019 contributed 28.6% of gross domestic product.

The Ineco report concludes that the construction of a new airport in Santo Antão is feasible and proposes that it be located in Ponta do Morro Preto, seven kilometres from Porto Novo

The second largest island by area, after Santiago (where Praia airport is located), is Santo Antão, which is 779 km² and the third most populated island, with more than 40,000 inhabitants. In 2003, the island’s only aerodrome, located in the north with a small runway of less than 600 metres, ceased operating for operational and safety reasons, meaning that its connections are now limited to the ferry line to neighbouring São Vicente. Despite this, its spectacular mountain scenery attracted more than 42,000 tourists in 2019, according to Cape Verde’s Directorate General of Tourism, a 20% increase on the previous year.

In 2016, the government, through ASA, launched preliminary studies for the construction of a new airport near Porto Novo, the island’s capital and home to a quarter of the population. On 5 March, the city hosted the presentation of the conclusions of the technical feasibility study prepared by Ineco, which was attended by the Prime Minister, Ulisses Correia e Silva, the Minister of Tourism, Carlos Santos, and other Cape Verdean authorities and public and private entities.

After mapping the area and analysing four possible locations, the winds, as well as taking into account the mountainous terrain of the island and the obstacles to aircraft operations, the Ineco report concludes that the construction of the airport is feasible. After considering several criteria, the proposed location is the Ponta do Morro Preto area, seven kilometres from Porto Novo. This area was selected as the most suitable because of its proximity to the city, which would make it more convenient for future passengers, and because it would require less earthworks than the other options, making construction cheaper and easier.

The runway is expected to be 1,400 metres long, which could be extended to 2,000 metres, suitable for the medium-sized aircraft that make up the fleet of the airlines that will operate at the new airport. In order to determine the runway orientation, which is essential to ensure safe operations, a detailed analysis of the data collected over the last four years by the weather station, which was installed in the area in 2017, has been carried out. In this way, it has been established that the predominant winds are east-southeast, which dictates the orientation of the runway for the approach maneuvers, the most delicate, and the take-off.

The Ineco study also includes an analysis of the tourist demand that the new airport would generate, using the Spanish islands of La Gomera and El Hierro as a benchmark. Following the confirmation of the technical feasibility of the project, a ‘road map’ of the next steps was presented: the completion of a preliminary flight procedures study, the preparation of a Master Plan including location alternatives, a demand study and a cost-benefit analysis, a Strategic Environmental Assessment, and finally, construction and operation authorisations.

An Instrument Flight Procedure (IFP) sets out the manoeuvres and trajectory that an aircraft must follow to safely enter and exit airports, avoiding obstacles.

The International Civil Aviation Organisation (ICAO), which is responsible for promoting the safety, efficiency economics of international air transport, considers instrument flight procedures to be an essential component of the aviation system. It is therefore essential that these procedures be designed to meet strict quality requirements, such as those contained in the Quality Assurance Manual for the design of flight procedures. The European Commission, within the framework of the Single European Sky, has also published a specific regulation, ADQ (Aeronautical Data Quality) which complements and reinforces the requirements defined in ICAO Annex 15.

In order to meet all of the quality requirements of international standards, specific software tools are required, in order to automate the design process and ensure the accuracy, precision and integrity of the aeronautical information on which air navigation depends. This is the context for EOS, a new software product developed entirely by Ineco as a corporate tool for the design of flight procedures. Following the completion of the development and internal validation phase in December 2019, EOS is ready to be put into production flight procedures based on area navigation (RNAV) as well as on conventional navigation.

What is EOS?

In order to design an instrument flight procedure, a set of areas and surfaces associated with the nominal track of an aircraft are defined, where existing obstacles and terrain are assessed with an appropriate Minimum Obstacle Clearance (MOC).

EOS reliably and efficiently performs these spatial geometric calculations, combined with a GIS and a 3D visual interface. The application is also capable of assessing whether terrain obstacles and elevations could affect the flight safety of an aircraft following that associated nominal trajectory. These trajectories may be those corresponding to departure manoeuvres (SID), arrivals (STAR), approaches (APP), ATS routes and holding procedures.

It is a desktop application, developed in Java within the NavTools suite also created by Ineco, for the management and use of digital terrain models (DTM), and is compatible with other proprietary tools for the study of rights of way, radio conditions and CNS systems in the airport environment. It is supported by the GIS developed by NASA, (NASA WorldWind) using highly accurate digital terrain and surface models to recreate each scenario.

An example of a conventional approach with a guidance section based on a DME arc.

Project development

EOS was developed as an internal innovation project by a multidisciplinary team, made up of aeronautical, telecommunications and computer engineers, with extensive experience in IFP design spanning more than 10 years.

In very broad terms, air navigation, since its origins, has evolved from being strictly visual to relying more and more on technology as it evolved, making instrument navigation possible. At the start of the 21st century, the multiplication of specifications, systems and equipment, as well as increasing airspace congestion, made it necessary to move towards the unification of standards.

The geometric aids to support the construction of the protection areas.

Consequently, area navigation or RNAV has given way to a new concept promoted by ICAO since 2008: PBN, or performance-based navigation, as opposed to sensor-based navigation, i.e. physical equipment (VOR, DME, ILS, NDB, etc.). PBN has been increasingly used by air navigation service providers around the world for the development of new instrument procedures because it facilitates their design and enhances the utilisation of aircraft capabilities.

As the specifications for the design of flight procedures were developed along with the PBN concept, shortcomings in the commercial tool in use at Ineco became apparent. This led to the development of a new proprietary tool, EOS, which, in addition to providing new features, allowed for a faster implementation of changes.

The project was implemented and managed using the software development methodology implemented at Ineco, CMMI level 3. It complies with the ADQ (Aeronautical Data Quality) since it is based on the AIXM 5.1.1 standard (aeronautical information exchange model, see IT 70) that is required internationally.