Flight services to-and-from the national capital's Indira Gandhi International Airport might be interrupted due to medium-heavy fog conditions expected to commence from the third week of December.
"We are expecting foggy conditions to set in from the third week of December to mid-February around the airport," said R.K. Jenamani, director in-charge, meteorological watch office, India Meteorological Department, IGI Airport.
"It is estimated that the foggy conditions might last for 90-120 hours this season."
A total of 289 flight diversions were caused due to fog in the last three winters from Delhi airport.
In 2011, it was 54; it was 89 in 2012 and 143 in 2013.
In April, a panel of the aviation regulator (Directorate General of Civil Aviation) recommended several steps like upgrading of infrastructure, meteorological facilities and runway radar coverage to achieve zero diversions from the Delhi airport.
It had recommended that airports near Delhi like Jaipur, Lucknow and Amritsar, should be upgraded to category-III B level of instrument landing system, which provides visual and sensory guidance to land aircraft in range of 150-50 metres.
IGI airport uses CAT-III B of ILS.
An aircraft can land at the Delhi Airport with a visual range of around 50 metres by using the CAT-III B ILS system, however, it can only take-off between visibility range of 125-150 metres.
Airlines are also advised not to operate propeller or other aircraft like ATRs or Q400s which are not equipped with CAT-III B ILS on-board. Special training to pilots and aircraft crew is also required under guidelines to operate to Delhi during the fog-period.
Airlines and airport operators too have been advised by the DGCA to provide up-to-date flight information to passengers. Passenger carriers are also required to provide refreshment and resting facilities for passenger affected by fog delays under DGCA's guidelines.
There are also 11 stand-by airports like Jaipur, Lucknow and Amritsar, which are pre-pared to handle diverted flights from Delhi during the season.
This year though the Delhi International Airport Limited (DIAL), seems confident of a smooth operations season during foggy conditions.
"We have all the mechanisms and infrastructure in place to handle any situation during the fog condition," Marcel Hungerbuehler, chief operating officer, DIAL told IANS.
"In addition we might be able to use runway 27 for take-offs for the first time this foggy season. This will provide us with great efficiency in declogging the airport during foggy conditions."
