Darkness lingers

Calcutta, Aug. 27: The special Category II lights installed at Calcutta Airport’s primary runway will in all probability lie idle this winter.

Chimneys and tall trees lie in the path of the lights, which are meant to enable planes to take off and land in dense fog. There has also been a delay in installing a runway visual range machine, a component crucial to operating the lights.

“There are several tall chimneys and trees on the flight path of CAT II which are penetrating the safety surface,” airport director V.K. Monga said. “We have held several meetings with the district administration and it has been agreed the obstacles will be removed.”

But a fresh survey will have to be made to check if there are any further impediments in the way of the lights. This cannot be done before winter.

Aerial surveys conducted by the Airport Authorities of India (AAI) had revealed that at least three chimneys are penetrating the flight path of CAT II. “We have asked the owners of the factories on which the chimneys are located to lower them. The Madhyamgram municipality has been asked to cut the coconut trees. They are looking into it,” said M. K. Panth, district magistrate, North 24-Parganas.

Planes have to fly at a higher altitude under Category I lights. “However, once CAT II is operational, the flights will fly at lower heights when they are landing at Calcutta Airport. In that case, the chimneys and trees could pose serious threats to flight safety,” Monga said.

According to AAI officials, a ground survey will be conducted to detect other obstacles. “The survey will start soon,” Monga said.

It had taken the authorities a little more than a year to set up the CAT II lights on the primary runway. The installation involved setting up bright lights on a 900-metre stretch along the “centre line of the runway”.

Once the CAT-II facility is in place, pilots can land even if visibility is 350 metres. AAI officials said this was good enough for Calcutta’s weather conditions. At present, a pilot cannot risk landing if the visibility is less than 800 metres.

The minimum decision height ? the height from which a pilot takes the decision to land ? will be reduced from a minimum of 60 metres to a minimum of 30.

At present, two Vaisala Transmisso Meters (VTMs) are in operation at the two ends of the primary runway. The two poles ? one sending signals and the other reflecting it ? give digital readings of visibility conditions on the runway. In the CAT II system, another VTM machine, to be imported from Finland, will be installed.

Although the site has been selected and work is in progress, Met department officials at the airport said the machine is yet to be bought.

“We have held talks with AAI authorities at Delhi and they are keen to start CAT II operations as soon as possible. We have requested them to buy the machine to make things faster,” said A.K. Das, director-in-charge, Met department, Calcutta airport.

“However, it will be difficult to start operations this winter.”