Air traffic control surveillance and communications, weather information dissemination Air traffic control and navigation
Overall there are few air traffic control installations in Africa. The North African countries with heavy traffic—Morocco, Algeria, Tunisia, and Egypt, currently have or have planned radar installations. In Sub-Saharan Africa, the main countries of Kenya and South Africa have the heaviest installations. Also Nigeria, Ghana, Tanzania, Uganda, and Zimbabwe are equipped.22 The rest of the continent seems without coverage, including Ethiopia, which acts as one of the important hubs. In some countries, such as Malawi, some surveillance coverage existed in the past, but as equipment aged and became too expensive to maintain, it fell into disrepair, and is now no longer salvageable.
Even when the equipment exists, this does not mean that radar separation—where the controller uses radar returns to establish the position of the aircraft, and issues directions and headings based on the image of the radar—are implemented. In Kenya, for example, only Nairobi has full-time radar vectoring, whereas Mombasa only switches to radar procedures if weather conditions so demand. Tanzania, though having a good radar installation in Dar es Salaam, with a secondary radar having an excess of 300 kilometer range, has no radar vectoring due to a lack of radar-certified controllers. Ugandan radar services were provided by the military, only in an advisory manner, using aged technology (a new civilian system has been installed in the last year).
The need for radar coverage in most African countries falls in between vital and not so vital, but “good to have” infrastructure. But, in order to make sense of Africa’s needs, some clarifications need to be made.
Radar is only one form of surveillance technology that allows an air traffic control center to locate an aircraft in the center’s airspace. Other, newer and more precise techniques include having the aircraft broadcast its position to a ground station, which then relays the information to the air traffic control center. If the position is obtained by the aircraft using modern Global Positioning System (GPS) technology, the inherent errors in radar technology are avoided, and accuracy of the position can be as close as 30 meters. This aids both in separation of aircraft, which is not a constraint in areas that are not very busy, and also in situational awareness for navigation. In some version of this new technology the aircraft does not only broadcast its position to the ground, but also to the aircraft around it, which then, if so equipped, can see the transmitting aircraft on a screen in the cockpit.
The modern trend will away from radar installations to these more advanced satellite-based technologies (one term often used is Automatic Dependent Surveillance-Broadcast, “ADS-B”), at a fraction of the cost of radar, even if aircraft need to be reequipped. Given these developments the term “radar” may well be obsolete when discussing future infrastructure investments. In this sense, the term “surveillance system” would be more appropriate when discussing methods of locating aircraft in the sky, and “ADS-B” would be the terms applied to specifically broadcast-type surveillance, where the aircraft transmits its current position.
The benefits of a surveillance system, even in less heavily traveled areas, can be listed as follows:
A surveillance system lets a controller know where an aircraft is at all times, even if that controller is not communicating with the aircraft.
A precise surveillance system can pinpoint the location of an accident much faster and more accurately than traditional radar.
A surveillance system allows much tighter separation of traffic (from 80 kilometers to roughly 8 kilometers), giving controllers the freedom to allow aircraft to fly more fuel-efficient paths and approaches.
A surveillance system becomes a must when flying involves bad weather, such as during the rainy season in many countries.
In addition, a surveillance system using a specific ADS-B type of technology can let the pilot see other aircraft in the vicinity, as well as information, such as weather updates.
Africa could clearly benefit from additional, low-cost surveillance technology, especially in the areas busy with overflights. Though current traffic in many regions would not justify the expense of purchasing radar systems, which can cost more than four times as much for the same coverage, with very high maintenance costs, the introduction of ADS-B in order to fill surveillance gaps would be a good solution. In fact South Africa is considering incorporating ADS-B in a planned redesign of the airspace over the Southern Africa Development Community (SADC) region.
Navigation installations are also sparse. Figure 2.6 provides a current map of ICAO’s showing existing installations. North Africa is better equipped with radio navigation aids, as is the main corridor along the east stretching from South Africa to Egypt. But, radio navigation aids are also expensive to install and maintain, and do not provide the precision now available with GPS. For navigation in Africa the future lies in GPS, with aircraft carrying their own infrastructure, and airports developing approaches taking advantage of the technology.
Figure 2.6 Installations of ground-based navigational aids in Africa
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