Heavy fog disrupts flight operations at Kolkata airport

Kolkata: Owing to heavy fog causing low visibility conditions, flight operations were affected at Netaji Subhas Chandra Bose International (NSCBI) airport, Kolkata on Thursday morning leading to diversion of 12 flights and delay in arrivals and departures.

According to data shared by Airports Authority of India (AAI), Eastern Region, a Bangalore to Kolkata flight was diverted to Bhubaneshwar at 7:36 am. A Delhi-Kolkata flight was diverted to Ranchi at 7:39 am. An Ahmedabad-Kolkata flight was diverted to Bhubabneshwar at 7:40 am. A Mumbai-Kolkata flight was diverted to Bhubaneshwar at 7:46 am. A Bangkok-Kolkata flight was diverted to Bhubaneshwar at 8:03 am.

In total, among 12 incoming flights, seven were diverted to Bhubaneshwar, three to Ranchi, one to Chennai and one to Shamshabad.

The total number of flight delays in arrival is 21 and in departure the figure is 39. Two flights had to return to parking bays from the ramp. No flights were, however, cancelled. It was learnt that flight operations were affected between 5 am and 10 am. Visibility began improving after 9 am and things were normal around 10 am Passengers were inconvenienced due to delay in morning flights and such delays had an apparent cascading effect throughout the day, AAI sources said.

It was learnt that visibility had dropped below 50 metres. The category (CAT) III-B Instrument Landing System (ILS) at the airport helps trained pilots to operate in a visibility range of 175-50 metres but not below 50. This is below the permissible limit for commercial aircraft operations.

The ILS has an approach lighting system (ALS) that assists the pilot in transitioning from instrument to visual flight and to align the aircraft visually with the runway centreline.

The ALS helps the pilot to continue descending for landing towards the runway even when the runway lights are invisible due to fog or heavy rainfall.