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a performance-based, coherent, fully harmonised set of rules at European level in the coming years.
THE NEED F0R BACK-UP SYSTEMS
Air Navigation Service Providers' (ANSPs') and EUR0C0NTR0L's efforts to improve the management of air traffic in congested European skies has resulted in the introduction of new Air Traffic Management (ATM) systems, which allow for more efficient and safe handling of both commercial and military flights, freeing up air space and enhancing performance of traffic. But, the intro¬duction of more efficient ATM systems calls for caution. As more powerful equipment enables more aircraft to operate within
a confined space, the reliability of the systems becomes abso¬lutely paramount. Any partial or complete malfunction could be catastrophic. Realising this, a number of European Air Navigation Service Providers (ANSPs) have installed back-up systems that are completely independent of their main ATM systems.
The Irish Aviation Authority (IAA) has implemented the TERADS system developed by the Danish company, Terma. The main function of TERADS is to work as a 'hot standby' system, enabling Air Traffic Controllers to clear the skies should the main system malfunction. In short, it is a tool which is sufficiently safe to allow aircraft to land or be handed over to other controlling authorities in a neighbouring air space.
The IAA's key requirement for its choice of standby system was that it should provide full redundancy. Peter Nolans, Head of IAA ATM Systems and Technology explains: "We decided that we needed a fully independent back-up system, which would not need to draw upon main system resources, other than radar and our Aeronautical Fixed Telecommunication Network. The system needed to be able to be put in operation in a matter of seconds to enable continuous situational awareness."
Nolans goes on to say: "TERADS turned out to suit these
requirements very well. It is running on a completely parallel system using independent servers and computers. There is no start-up procedure because it is in continuous 'hot operation'. The ATC can simply alternate between main and back-up sys¬tems by pressing a switch on the monitor."
Another ANSP, the Danish Naviair, has already bought more than 50 workstations running the back-up system, including 46 in Copenhagen Airport alone, and is a major advocate of fully independent back-up systems. Bent Fog, Naviair's Technical Maintenance Director, reveals how exacting Naviair's require¬ments were: "We demanded that our back-up system should be fully redundant. For example, the TERADS computers should be assembled from components separate from those of our main system. The real advantage for us is that we are 100 per cent certain that we can clear the skies, should our main system mal¬function. In principle we could continue to carry out operations without a fully redundant back-up system, but we decided to eliminate this risk, and the cost proved not to be prohibitive."
Their favourable experience with the new equipment has led them to apply for approval of TERADS as a supplementary main system, rather than just a back-up. This will allow it to be used more often as a main system, when the actual main system is shut down for upgrades and/or maintenance. Fog explains: "When we are maintaining our main system during low traffic periods, we can run our operations on TERADS. This is a really significant added benefit, beyond the added safety element."
Similar back-up systems are already functioning as main systems in several Norwegian airports, so Fog hopes that the Danish CAA will look favourably upon Naviair's request.
Additionally, the European Commission has asked the European Civil Aviation Con¬ference to conduct a study on General and Business Aviation that would identify the sources of available safety data and suggest the most efficient way for its future gathering.
Apart from looking inwards and
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本文链接地址：EUROCONTROL EBAA IAOPA Yearbook 2009: The Business of Flying(37)
