Airport expansion plan under scanner

It will result in dislocation of 947 houses; High Court verdict on land acquisition soon

CHENNAI: A verdict is expected from the Madras High Court within a week on the Airport Authority of India’s land acquisition plans, but the debate on the merits of its airport expansion project rages on.

While the AAI maintains that the Rs.2,700-crore project, which will result in the dislocation of 947 houses, is crucial to Chennai’s future as a key aviation hub in India and South Asia, experts have raised questions about the necessity and merits of the plan in light of what they perceive to be inefficiencies in airspace use and the cost of displacement.

When the AAI first conceived the plan to expand the airport four years ago, it had forecast that Chennai would need to handle around 50 aircraft movements an hour by 2015. According to the AAI, the expansion plan will enable Chennai to handle traffic growth until 2016. The AAI expects the greenfield airport — Sriperumbudur is the likely location—to be ready by then.

Cross runway concerns


While the initial plan was to build a parallel runway, the AAI now also plans to extend the cross runway that has been in operation since December. The extension is the main cause for the dislocation of 947 homes — the land for the parallel runway plan is largely poromboke land, which the AAI has received clearance for acquiring (see graphic).

Airport sources say though the AAI is continuing its push for expansion, it is now reconsidering the parallel runway plan. There are, however, a number of logistic constraints in operating a cross runway. Air Traffic Controllers feel that it is not ideal for managing traffic; unlike in a parallel runway set-up, intersection of two runways imposes restrictions on speeding up aircraft movements.

The usage of the cross runway is also heavily reliant on wind patterns, and it cannot be used for three months every year. Strengthening of the clayey soil around the banks of the Adyar — the cross runway will be extended across the river — is also expected to cost a huge sum.

Airport officials also say airspace is currently not being used at full efficiency. While there have been several proposals to construct rapid exit taxiways to minimise the lag between consecutive aircraft movements, the AAI has not yet started work on them. “The absence of rapid exit taxiways makes up 40 per cent of the problem,” says an airport officer. “Rapid exits would allow aircraft to be cleared in half the time.”

Rapid exit taxiways will allow aircraft to be cleared with a separation of four miles between them (ATCs currently follow an eight mile separation rule). Rapid exits will also allow aircraft to exit at a speed of 55 knots, but on the current exits, aircraft movement cannot exceed 30 knots.

“Given that Chennai currently handles 28 aircraft movements an hour, and rapid exits would, logically, allow them to double the aircraft movements to 56, what then is the need for expansion in the first place?,” asks former pilot Capt. A. Ranganathan.

Another hindrance to the construction of the rapid exits is the presence of the old air traffic control tower near the end of the cross runway. “Requests have been made to demolish the old building since 2004, but nothing has been done,” an airport source says.

http://www.hindu.com/2008/03/27/stories/2008032759311200.htm