Software glitch blamed for air traffic shutdown
Aviation chiefs said a software glitch was responsible for an Air Traffic Control (ATC) problem over the southern part of Ireland which effectively forced the temporary closure of segments of Irish airspace.
The Irish Aviation Authority (IAA) said that, following a detailed investigation of its Ballycasey, Co Clare, ATC centre, the problem was identified.
"The issue was an irregular software occurrence," an IAA spokesperson said.
The issue has been resolved and Ireland's primary ATC in the south has been restored to full capacity.
Tuesday night's problem primarily hit air traffic to Shannon and Cork airports - with Dublin Airport unaffected because it operates on a different ATC centre.
IAA officials stressed that the ATC system was only brought back on stream after "comprehensive testing and safety analysis was carried out to ensure that the system was fit to return to operations".
Authority officials also insisted that its support systems operated as required when the problem emerged on Tuesday.
"We are satisfied that the back-up system and contingency planning worked as required. This ensured that we restored full service in a safe and timely manner and disruption to aircraft was minimal," a spokesperson said.
The IAA stressed that the issue involved was not a radar problem, with full radar coverage maintained at all times.
The problem was confined to a module on the ATC system which affected the performance of the system.
IAA officials insisted that the back-up system is a full replica of its main ATC network - allowing for full, normal operations to be conducted.
Initial investigations ruled out any suggestion the problem was linked to a security breach such as a hacking or cyber attack.
Flights operating to both Cork and Shannon airports were hit by the radar flight tracking problem, which was first detected after 6pm on Tuesday.
The Ballycasey ATC centre covers key sections of Irish airspace in the south and along the transatlantic approaches to both Shannon and Cork airports.
When the technical problem emerged, it was decided that Ireland would have a zero-flow rate for the sections of airspace involved - no aircraft would be allowed use the ATC sections involved beyond those already there.
IAA technology director Philip Hughes said the decision to close airspace sections was taken with the overriding priority of passenger safety.