Eurocontrol, the European Organisation for the Safety of Air Navigation, said about half of flights travelling across Europe could be subject to delays after a system failure at about midday on Tuesday. The unspecified problem was with the Enhanced Tactical Flow Management System, which helps to manage air traffic by comparing demand and capacity of different air traffic control sectors. 'Contingency procedures are being put in place which will have the effect of reducing the capacity of the European network by approximately 10 percent,' the agency said. It added that air traffic control had not been directly affected and “there are no safety implications arising from this incident.”

Brussels airport said departures were limited to 10 flights an hour. Earlier in the day, several European airports had warned passengers to expect delays, with Brussels Airport saying it was limited to just 10 departures every hour. Work to restore the system was under way after the problem was identified, but it was unlikely to be in operation before the evening.
An air traffic control system failure in Europe delays up to 15,000 flights, according to the European Organisation for the Safety of Air Navigation.