How the 2010 Icelandic ash cloud disrupted eight days of European flights

The main disruption lasted from 15 to 22 April

EUROCONTROL estimated about 104,000 cancellations over eight days, about 48% of expected reference-area traffic. The reference-area rate reached 80% on 18 April. The report describes additional localized disruption in May. Source 1 Source 2

The highest-loss day varied across airspaces

On 15 April the reported estimated cancellation fraction was 92% in Norway and 39% in Finland. On 18 April it was 77% in Norway and 100% in Finland. Looking at the full period, Finland reached 81%, ahead of Ireland and the United Kingdom at 74% each. Source 1

An airspace loss can reflect rerouting

EUROCONTROL estimates expected flights using surrounding traffic patterns and notes that an aircraft rerouted around a particular block of airspace can count as missing there. The report groups some countries into one airspace and treats flight information regions separately in other cases. The reference-area estimate is an aggregate for its stated coverage. Source 1

Iceland’s disruption followed a different calendar

The report examines Iceland separately because the effects persisted longer and the underlying data were organized differently. It says Icelandic traffic was affected for 13 days in April, and in May some North Atlantic flows shifted north of the ash. EUROCONTROL later reviewed how network crisis management changed after the event. Source 1 Source 3

Sources

• EUROCONTROL report on April and May 2010 ash-cloud traffic disruption
• EUROCONTROL publication summary and report scope
• EUROCONTROL retrospective on the ash crisis and response