In efforts to reduce the impact of fog on flight operations, the Delhi airport, the country's busiest, is set to begin the live trial of advanced fog forecasting technology that can predict dense fog hours in advance, giving aviation authorities crucial time to plan and prevent the kind of disruptions that paralysed flight operations last year.
The Winter Fog Experiment (WiFEX) system is an Indian field campaign designed to understand and improve fog prediction over northern India, particularly across the Indo-Gangetic plains.
"The modelling can provide predictions for Delhi airport around 36 hours prior giving sufficient time to prepare for flight operations. We will be taking a live trial of this system for the first time in December," said Videh Kumar Jaipuriar, the chief executive officer (CEO) of Delhi International Airport (DIAL), which handles Delhi airport.
"It will go live at the airport from next month," he added.
The system has been developed by the Indian Institute of Tropical Meteorology (IITM), Pune, in collaboration with the India Meteorological Department (IMD) and the Airports Authority of India (AAI). It was launched in 2015.
Under WiFEX, he said, sensors have been installed at various locationsat the perimeter of the airport. It then integrates field instruments, real-time meteorological data and high-resolution models to predict fog formation, persistence and dissipation.
The main WiFEX siteuses a network of instruments, including lidars and ceilometers to measure fog height, radiometers and flux towers, to track humidity and surface radiation, wind profilers, weather stations, and balloon sensors to capture minute-by-minute changes in temperature, dew point, wind and visibility.
"If it performs as expected, it will give us advance notice of dense fog conditions, allowing better coordination between airlines, ATC and ground units," Jaipuriar said.
Delhi airport, in terms of actual infrastructure, has also completed a critical upgrade long overdue -- making both sides of the airfield CAT-III compliant for low-visibility operations.
Last winter, easterly winds exposed that only one runway (28/10) supported CAT-III landings, cutting arrival capacity from 42 to just 15 flights per hour. This year, the 10-end of the same runway has been upgraded and promulgated for CAT-III use, and will become operational by November 27. That means both the easterly (runways 10 and 11L/11R) and westerly (runways 28 and 29L) configurations will be CAT-III capable, maintaining roughly 30 landings per hour even in heavy fog.
Officials believe that this will sharply reduce the cascading delays seen last year, allowing schedules to recover within a couple of hours once visibility improves.
"Our main challenge happens during easterly winds. Last year, during easterly flow, it used to take us 6 hours to recover an hour of disruption against which it will take us a maximum two hours to get over the disruption so that is the kind of improvement that we are expecting, "Jaipuriar said.
The airport has also increased the number of 'follow-me' vehicles, with an aim to vacate all runway crossings, and revalidated all critical and sensitive areas to ensure safe low-visibility operations.
To manage the crowd in the terminal buildings, the airport has commenced using a system -- airport predictive operation centre (APOC) -- that generates data that is shared with all stakeholders like airlines, Central Industrial Security Force (CISF) , Bureau of Immigration. It gives the airport a somewhat accurate passenger footfall expected each hour, allowing personnel deployment at all touch points like terminal entry, check-in, security check and immigration.
"This sharing of data has already cut wait time at security check by 15%... There are also meetings being conducted with all stakeholders as part of fog preparedness," Jaipuriar said. "With all these initiatives, DIAL expects smoother passenger and flight operations in the upcoming winter and fog travel."