Airports of Thailand Plc (AoT) is to partially close one of the two runways at Bangkok's Don Mueang airport for repair work this month.
The first of the two-stage project at the eastern runway, codenamed 21 L/03R, will reduce the airport's flight-handling capacity from 40 to 36 per hour.
AoT president Nitinai Sirismatthakarn acknowledged that the reduction in capacity was expected to worsen congestion during the three peak traffic periods of 9-10am, 1-2pm and 5-8pm while the work is undertaken from Sept 10-22.
The repair involves 500 metres of the 3,500m runway where aircraft normally touch down.
However, the second stage of the repair work for the runway, involving another 300m, is not expected to cause disruption because work will be carried out between 8pm and 6am from Sept 23-26.
Don Mueang's other runway on the western side -- 21 R/03L with a length of 3,700m -- will remain in operation.
The repair of the eastern runway is meant to prepare Don Mueang for higher traffic in the forthcoming high season.
Mr Nitinai said AoT was working with agencies concerned with air services to minimise the impact of the runway repair.
Meanwhile, airline executives said the runway repair would worsen the already crowded situation at the airport, whose use has stretched beyond its current capacity of 18.5 million passengers a year.
The renovation of Don Mueang's Terminal 2 and other facilities, which were due to be up and running this month, has been hit by a further delay, depriving the airport of a capacity increase.
AoT now expects the renovation, which will boost the airport's annual passenger-handling capacity to 30 million, to be completed later this year.