Auckland Airport says a review has found that hot weather contributed to problems that led to urgent closures of its runway - which it concedes took longer to repair than they should.
An internal review has identified ways of speeding up maintenance repairs following disruption to 60 flights and thousands of passengers during two runway outages on January 24 and February 6.
The latest closure prompted an international alert from pilots about the risk of large chunks of concrete on the runway near the eastern touch down zone and a warning to make sure they had enough fuel to divert to other airports.
The airport's chief executive Adrian Littlewood has ruled out compensation for the affected airlines.
The company said faults can sometimes occur in the concrete which is up to half a metre thick and hot dry weather can increase thermal expansion. But replacement of paving slabs may not happen until later this year.
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Littlewood said some of the recommendations on improvements to response times to incidents and a new inspection regime had already been implemented.
It has now increased monitoring and resourcing, including doubling the frequency of daily airfield inspections.
"The two recent closures were longer and management takes full responsibility for the
delays and we apologise to the people who had their travel disrupted by these events,"
He said the airport remained confident in the safety and integrity of the runway and airfield maintenance programme, which he said was endorsed by independent experts.
The airport - which tomorrow announces its six-month result - had said the review would take three weeks but had finished it early given what Littlewood said was its importance.
The review found the restricted runway operations in January and February were 43 and 68 minutes respectively – longer than the 20 minute-period that should have been
required to carry out the maintenance works.
This was because of the time to assemble specialist tools, the location of certain resources and the methods chosen to remedy the faults.
On both occasions the review found certain tools could have been made available in a more readily accessible location to speed up the response time. At the time of the most recent incidents our on-call maintenance response teams were working well away from the impacted area and it took time for them to relocate.
More repair kit would be positioned closer to the runway for ''rapid response requirements. Further training will also be provided to support decision making in risk assessment and remediation methods.
The airport has faced criticism for the way it manages aeronautical assets compared to others such as retail outlets.
Littlewood said the runway - first built in 1965 - was its key asset.
Between 2015 and 2019, $48 million has been spent on pavement replacement and airfield maintenance.
It would invest heavily in its airfield with $720m to be spent over the next four years in upgrading, maintaining and expanding the airfield.
The company said it has been consulting with aviation authorities and independent
experts on planned runway works.
Design and procurement are already underway for long-lead items and new jet blast deflector fences to protect work sites during runway works.
The airport discussed the runway works with airlines last year and identified timing options for the pavement replacement to take place, with the airport's preference being September this year.
''At the moment September is our preference but we'd have to talk to the airlines about that. It's really about the best windows from a technical construction point of view, weather and how it influences concrete curing.'' said Littlewood.
The Board of Airline Representatives said the closures had a major impact on travellers and airlines.
"While safety always takes precedence, the travelling public deserve the need for urgent runway closures to be kept to a minimum," said Barnz executive director Justin Tighe-Umbers.
"Future runway pavement replacement works will have an impact on airline schedules
and flights, so it is key the airport gets the timing right.''