Work on Auckland Airport's runway will begin tonight as part of a $26 million project to replace pavement in the main touchdown zone.
Jet-blast fences will be transported onto the runway and from 11pm, 80 workers will begin work to shorten the airport's runway by 1.1km in order to replace 280 concrete slabs at the eastern end.
The airfield will remain operational through the work, which was originally planned to begin later in the year, but was brought forward due of Covid-19 and the significant reduction in the number of flights.
Construction is expected to last between eight and 10 weeks.
"The runway is New Zealand's main connection point to the world, and in the months and years ahead it's going to play a critical role in our country's economic recovery," said Andre Lovatt, Auckland Airport's general manager of development and delivery.
"The outbreak of Covid-19 has had a sudden and severe impact on everyone in the tourism industry, including Auckland Airport, and while we miss the excitement of travellers, it was clear we had an opportunity to move the pavement works forward and get the project under way earlier."
Planes would continue to land and take off throughout the work using a technique called "displaced threshold", which allows runway works to be carried out safely while the runway remains open, Lovatt said.
He the programme would create work for 150 people and would mean up to 120 truck movements daily, bringing in concrete and other materials.
The 36sq m slabs are on the part of the runway where most planes land. Around 12,000 tonnes – the weight of 21 fully loaded A380s – of concrete will be poured, measuring 500mm thick.
Jet-blast winds from a B777 at take-off can reach up to 300km/h. Workers will be more than 200m behind departing aircraft and protected by blast fences, which dilute and deflect the force of jet engines.
Auckland Airport last operated with a displaced threshold during routine maintenance works in 2016. It allows all aircraft types to safely land and take off.
Lovatt said in normal circumstances, a displaced threshold method could result in the need for airlines to reduce aircraft weight, but with fewer fully laden aircraft flying it was less likely.
"These new runway slabs will be robust enough to handle the heaviest and largest aircraft, taking off at weights of up to 575 tonnes," he said.
Replacing runway pavement is a critical component of Auckland Airport's much reduced infrastructure development programme over the next couple of years, which prioritises selected capital projects focused on essential safety and asset maintenance, Lovatt said.
Auckland Airport has a continuous programme of replacing and renewing slabs, which were last replaced in the mid-section of the runway over the summer of 2006-2007.