The Netaji Subhas Chandra Bose International Airport in Kolkata has become the fifth in the country to have a CAT III-B ILS for countering fog. The advanced system lets flights operate in visibility levels as low as 50 metres.
Kolkata’s Netaji Subhas Chandra Bose International Airport has started the implementation of CAT III-B Instrument Landing System (ILS), an advanced system that allows flights to take-off and land till the visibility drops below 50 metres.
The airport has become the fifth airport to be equipped with CAT III-B ILS, after Delhi, Jaipur, Lucknow and Amritsar. Every winter, especially during the months of January and February, flight operations at airports in northern India are affected due to dense fog. Although stakeholders such as the Airports Authority of India (AAI), and the airlines and meteorological department take steps to work through intense weather conditions, flights get delayed. The placement of such a system is thus needed as it is far more beneficial in dealing with unpredictable weather.
Foggy days have seen about 2,500-5,000 passengers being stranded at the airport in Kolkata leaving the facility chaotic.
“On days when extreme fog developed, operations were usually suspended between 5:30am and 8:30am. By the time the flights resumed, the terminal used to burst at the seams. There was a space crunch with not enough seats available. Washrooms turned messy. Outside, the car park got flooded with vehicles. Passengers were hugely inconvenienced, particularly the young and elderly and those with onward connections. The situation put terminal managers and airline officials under huge stress. With CAT III, those harrowing days should be over,” airport director Atul Dikshit was quoted by Indian media.
The CAT III-B ILS has been successfully operational at IGI airport (runways 28, 29 and 11), Amritsar (runway 34), Lucknow (runway 27), and Jaipur (runway 27).
The ILS reduces the minimum altitude required for a pilot to sight the runway end before making a decision to land or divert to an alternate airport. The system does this by giving the details of what is the ‘decision height’ that the pilot can use to make the decision of landing or re-routing to another airport.
The system, however, comes with its drawbacks. Although it will halt the diversion of flights and save authorities from bearing extra costs, it demands more precision and alertness on part of the pilots as the degree of error that can occur increases while flying in poor weather.
“In normal condition, a pilot gets comparatively more reaction time, and hence, the stress level is low. All CAT III approaches have to be on autopilot. That gives pilot less perspective, leading to higher stress. For any contingency like sudden disconnection of autopilot at the critical phase will require a pilot to be extremely alert and sure of his action,” veteran pilot Sarvesh Gupta explains the Indian press.
A level of alertness also has to be maintained as malfunctioning of autopilot can cause trouble when an aircraft is about to land in near zero visibility conditions.