The Telegraph
Wednesday , December 12 , 2012
Since 1st March, 1999
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Too foggy for plane to fly

Bhubaneswar, Dec. 11: Low visibility at a foggy Biju Patnaik airport has forced flights to be diverted to Calcutta in spite of precision landing systems here.

Yesterday, the AI 9601 New Delhi-Port Blair flight was diverted to Calcutta. Today, it was the turn of the 9W 2061 Mumbai-Bhubaneswar flight. Visibility was too poor here for the flights to land.

The morning fog has been dense over the past two days because of changed weather conditions. After being diverted, the flights returned and landed here after an hour or so, when visibility on the runway had improved.

The city airport is equipped with Category (CAT) I instrument landing system (ILS), which allows landing of flights when the runway visibility is a minimum of 500 metres. When the visibility is lower than that, flights have to be diverted to the nearest airport.

Better facilities such as CAT II and CAT III allows flights to land when the runway visibility is a minimum of 150 metre and 50 metre respectively.

“In an airport like Bhubaneswar, the CAT I system is ideal, as better facilities are not only more costly, flights also have to have them installed in their systems and pilots have to be trained in these precision landing systems. Higher CAT versions and their installation are a costly affair, and so they are only seen in bigger airports,” said airport director Sharad Kumar.

A source in the Airports Authority of India (AAI) said: “Practically speaking, the diversion cost of fights in extreme foggy weather conditions is comparatively lower than the all-told cost of precision landing systems installation in the plane and placing pilots in the respective training module. Airline operators are already hard-pressed because of rising aviation expenditure. So, they prefer to divert the planes to the nearest airport. Also, foggy conditions in an airport such as Bhubaneswar is temporary.”

The CAT landing system is controlled by radars and electronic equipment. A radar installed on the runway sends signals to the plane and the air traffic control tower. In a coordinated manner, the plane lands without any trouble on the runway even in low visibility conditions. The city airport has also got the ILS for night landing facility.

24X7 operation

The AAI officials plan to make the city airport operational 24X7 so that in extreme weather conditions, flights from nearby airports can land here between December 15 and February 15.

“During this period, it’s very foggy in airports such as the one in Calcutta. Therefore, preparedness here will allow flights to land here in case landing facilities at other airports fail to have the desired effect. The ATC can then advise the pilot to land at another airport with better visibility conditions,” said the airport director.

The 24X7 operations started for the first time last year on December 15. “We want to include another shift for the 24X7 operation. At present, the airport operates in two shifts from 6am to 10.30pm. We will need 25 more Central Industrial Security Force personnel, and extra staff. We will manage both over time,” Kumar said.

The 24X7 operation will be a regular affair once the city airport gets an international tag from the end of March next year. All international airports have to be operational 24X7, as flights from overseas usually arrive and depart at night.

Last year, besides helping operations at neighbouring airports, the 24X7 operation in Bhubaneswar was also instrumental in handling VIP flights for the Indian Science Congress.

Weather watch

The dense fog that has engulfed the entire coastal region of the state was the result of an anti-cyclone that has formed in the Bay of Bengal. “The anti-cyclone brings moisture from the sea to the nearby landmass. As the wind speed was low at eight-10km per hour, the fog remained concentrated and the intensity remained for a longer period at a low altitude within one km of the earth surface,” said Sarat Chandra Sahoo, director, Indian Meteorology Department, Bhubaneswar.

“Apart from the anti-cyclone factor, the foggy weather condition was caused by rise in the temperature, which in weatherman’s parlance is called inversion,” he said.

Met officials predict that the foggy condition is likely to continue for another day. There is a probability of rain in western, northern and eastern Odisha and once it rains, the fog will subside.