Centralised national contingency facilities provide fallback services at a single site for many/all ATM operations. These national facilities may or may not be co-located with other ANSP centres.
Single contingency centres can be developed to cover several ATM units. This reduces the costs over what would be incurred if contingency facilities were duplicated for each centre within a country. Infrastructure resources can be focused around a single contingency facility that can then be reconfigured for each area control centre (ACC) operated by an ANSP.
A single national contingency centre within each State will provide cover for all ATM service operations in one place. An appropriate strategic location for the central contingency facility should be decided. This is not simply a technical decision; it will be determined by the contingency policy, national infrastructures and geography. Political considerations may also need to be taken into account. If an ANSP’s common systems can be utilised for a Centralised facility, then opportunities for economies of scale will exist. During the early stages of a contingency situation, it may be possible to conduct a 'hot swap' from the ‘failing’ unit to the contingency facility before the 'skies are cleared' if the contingency facility is well supported and the configuration issues are relatively straightforward. However, this needs a greater degree of training and coordination which may be possible in a centralised facility within a single national system. Decisions should be made about the best allocation of human resources between any ‘failing’ unit and the centralised unit.