Passengers on NZ271 were told Oceania airspace was closed. Photo: Flight Radar
New Zealand's sole air traffic service provider Airways, says a software glitch is to blame for the weekend's air traffic control disruption.
The technical fault left five planes circling above Wellington and four others unable to take off on Saturday afternoon.
Airways chief executive James Young told Morning Report the fault, which lasted an hour, happened when flight data was unable to be transferred between systems.
"It affected air traffic control services between Australia and New Zealand," Young said.
"The fault itself was related to the processing of flight data from one system transferring to another system.
"We noticed that was not occurring as it should and as a result of that our air traffic controllers to measures to manage traffic, either by holding on the ground or in an air hold."
Airways operated a modern air traffic control system that involved back up systems but Young said they were not instantaneous and it took time to validate flight information data.
"At no point did we lose control of all aircraft. We were able to communicate with all aircraft and we had line of sight of all aircraft," Young said.
He said flights in the New Zealand air space were held, put into a hold with two eventually continuing on and three returning to origin.
"Aircraft operating in the Oceanic air space were able to continue to their destination as normal. What we couldn't do was process any changes to the flight path during the period of the outage, which lasted for about one hour."
Young said the fault was very rare and there was no evidence it was caused by a cyber attack.
"We do need to understand exactly what did occur. There's no evidence at all that suggests a cyber event or a cyber attack."
He said he had every confidence in the system and those who managed it.
"It's unusual. We haven't observed this before. We are now investigating into the root cause of what actually led to the issue."
The investigation would likely involve a simulation of the incident, he said.
Young said Airways had invested significantly in its systems in recent years and had secured funding for its next three year period which would allow for further investment and resilience.
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