Airports of Thailand Plc (AoT) is set to inject 2.5 billion baht to replace all 700,000 square metres of asphalt with concrete on all the runways at Suvarnabhumi airport to permanently solve the threat of "soft spots" that have been reported there.
The scheme is part of AoT's goal of improving ground safety conditions at the airport, AoT president Nitinai Sirismatthakarn said Tuesday.
The announcement comes after the International Federation of Air Line Pilots' Associations (IFALPA), which represents over 100,000 pilots and flight engineers in almost 100 countries, issued an alert last month specifying the risks of operating at Thailand's largest international airport.
The main risk was the discovery of several "soft spots" on taxiways, taxi lanes and aircraft stands at Suvarnabhumi. Flight crews and ground service providers have reportedly encountered these structurally unsound spots since 2008.
Suvarnabhumi officially opened for service in September 2006. At over 32 million sq m it ranks as the largest airport complex in Southeast Asia.
It was constructed over a large swamp known as Nong Ngu Hao, or "cobra swamp", since it was reportedly a habitat for snakes before it was built. This has resulted in a high water table below the airport.
"Suvarnabhumi is facing problems related to soft spots because it was built this way," Mr Nitinai said. "Two years ago, we began construction of a sub-drainage system, where the underground water is pushed out through pipes towards surrounding waters whenever the land is pressured, such as when planes land or take off on runways."
The sub-drains have reportedly been operational for one year.
Mr Nitinai said there are currently a minimum of 21 soft spots at Suvarnabhumi, adding 11 have already been temporarily fixed.
Authorities would be able to deal with the remaining soft spots by August.
He said airport staff are being deployed around the clock to check for problems on the runways.
AoT's planned replacement of asphalt with concrete will increase the life expectancy of its runways to 10 years before they need maintenance, as opposed to the current five to seven years, he said.
However, Mr Nitinai said it would take at least three years for the asphalt to be replaced by concrete as the airport can only close off 10% of its taxiways and taxi lanes at a time.
The IFALPA has advised airlines to alert flight crews to the existing hazards related to push back and taxi operations at the airport, and to apply appropriate operating procedures to mitigate risk.
