ABSTRACT
Emergencies in the ATM domain range from simple textbook scenarios to system wide failures that may lead to airspace closure. An example of the low end of the range regards aircraft requesting diversion to the nearest airport due to a system fault. This is a textbook scenario where controllers route aircraft to the diversion airport, providing adequate separation with other aircraft and managing coordination with adjacent units. Of course, several variations can be introduced to make this scenario more challenging (e.g., the flight crew may request to enter a holding stack to complete the relevant checklist). These emergencies happen nearly every day around the world and are successfully controlled. At the more complex end of the range, major system failures may affect ATM functionalities. An example is a software failure that led National Air Traffic Services (NATS, UK) to stop all departures from London airports and alter most flights from European airports that were planned to route through the affected UK airspace. This system failure posed many challenges to a large part of the European ATM network and required large scale changes in coordination and contingency planning in the face of airline and social pressures.
