Cybercrime or hacking were not responsible for the radar problem at Dublin Airport over the weekend which resulted in the suspension of all services for over an hour.
A technical issue triggered an outage, the Irish Aviation Authority (IAA) said in a statement on Sunday.
It is understood to be a software problem.
The authority also said the incident was not linked to issues last month on the west coast of Ireland when flights at Shannon and Cork were disrupted because of an “irregular software occurrence”.
The IAA said “the Dublin air traffic control system is completely separate to the system in Shannon and operates on a separate network.”
“This issue is unrelated to the recent [October] outage in Shannon.
“The issue yesterday morning was a separate technical issue which triggered an outage.”
The aviation authority pointed out that its system had been operating in Dublin since 2011 and this problem had not occurred previously.
“The IAA followed its contingency procedures in line with regulatory requirements and in the interest of the safety of the travelling public and flight crew. A full service at Dublin was restored at 9.35am yesterday morning.”
The interruption of service at Dublin Airport on Saturday began at 8.20am and lasted just over an hour. The authority said decisions to restrict operations were taken solely to assure the safety of the travelling public and flight crew.
The incident on the west coast last month affected the air traffic control hub in Ballycasey which services Shannon and Cork airports as well as transatlantic flights.
The IAA switched to a back-up system and lifted restrictions. A number of flights were postponed or temporarily diverted as a result.