Airport, armed with CAT-III tech, fields fog diversions from Dhaka, N-E
Times of India | 28 December 2025
Kolkata: The availability of Category (CAT) III Instrument Landing System (ILS) for the primary runway at Kolkata airport has ensured uninterrupted operations this winter, despite the city experiencing fog on multiple days during the week. On Thursday, a low visibility procedure was initiated after the runway visual range, or the distance a pilot can see runway markings or lights from the centreline of a runway, dipped to 550 m around 2.32 am.
The continued operations at Kolkata airport have helped bail out flights that were unable to land at Dhaka and Guwahati, which also experienced foggy weather but do not have CAT- III ILS to allow flights to land in poor visibility. In Kolkata, flights can operate in visibility as low as 50 m.
"On Thursday and Friday, Kolkata airport handled 18 diversions owing to dense fog over Dhaka and Guwahati. Of these, 11 were diverted from Dhaka and seven from Guwahati," an official said.
Though the northerly winds have ensured that flights have approached the airport from the southern side over New Town and taken off from the northern end of the runway, pilots said it was reassuring to know that both ends of the primary runway offer CAT-III ILS. This will ensure that flights can continue to operate in poor visibility conditions even if the wind direction changes.
"Kolkata airport has not yet been tested by dense fog this season. Only on one day, visibility was poor between 2.32 am and 4.05 am. But we are confident that even when there is thick fog, we will be able to carry on operations till visibility drops below 50 m," said an official.
"Thank you @AAI_Official, our true friend. When fog stopped planes from landing at night in Dhaka, Kolkata airport helped fast and gave a signal to land until the situation got better," a flyer wrote on X. A Bangladeshi citizen, Md Tariqul Islam, who was on one of the flights diverted to the city from Dhaka, said: "Due to dense fog, four out of eight flights have landed in Kolkata again. It seems we're all heading towards Delhi now."
Pilots who operate to the city said the availability of CAT-III ILS on both ends of the runway will improve the airport's operational reliability. They said it also has the potential to improve the operational efficiency of the runway. While the wind usually flows from north to south in winter, enabling flights to touch down only from the New Town end, changing weather patterns have meant changes in the wind direction that can affect flight operations in poor visibility conditions.
"If visibility goes down due to fog or heavy rain, flights can continue to operate irrespective of the wind direction. Since flights land against the wind, the airport can also change direction of operation according to the change in wind direction, without having to worry about visibility," said a veteran pilot.