Stansted’s single runway is to be fully resurfaced in five-month project that started at the weekend.
The work on the 3km long runway will take place at night to minimise the impact on the local community and airport operations.
It will be carried out five nights a week between Saturdays and Wednesdays.
The runway will be closed between midnight and 6am in the first 11 weeks, while it will remain open but at a reduced length to allow flights to safely continue operating during a second phase.
About 50,000 tonnes of asphalt will be laid over an area the size of 25 football pitches, and 1,300 runway lights will be replaced with energy-efficient LEDs over the course of the work.
Stansted’s runway last underwent full resurfacing in 2006, when the airport handled 15 million passengers, against 22 million last year and 28 million in pre-pandemic 2019.
The airport rescheduled its annual runway maintenance from overnight to daytime in April 2020 due to the impact of the Covid pandemic.
The reduction in flights allowed engineers access to the runway during the day when it would normally be busy with hundreds of aircraft landing and taking off.
Airport planning and development director Neil Thompson said: “Handling up to 50 aircraft movements an hour, the runway is obviously a key asset for the airport so it’s critical it is maintained to the highest standard at a busy international gateway such as London Stansted.
“A project of this scale is very complex and clearly presents us with a number of operational challenges as during just six working hours each night, we will need to remove and replace around 100 metres of runway surface before safely re-opening it before the first flight is scheduled to take-off in the morning.
“At the same time, we are upgrading the runway and taxiway lights with energy efficient, high performance LED lamps that are crucial in the safe operation of aircraft, especially in low visibility conditions.
“The whole project has been meticulously planned, and we aim to complete the work as quickly and safely as possible to limit the disruption on the operation of the airport and minimise any impacts for our local community.”