Operations at the Indira Gandhi International Airport in New Delhi on Monday went haywire after dense fog brought the services to a standstill for about one-and-a-half hours affecting the schedule of over 150 flights, including that of external affairs minister Salman Khurshid.
Khurshid's flight, which was to take-off from Palam Technical area for Bhutan around 9.30am, was delayed by two hours as it was caught in dense fog, sources said.
Flight operations at the airport came to a standstill for around one-and-half hours, between 5am and 6.30am, as the runway visibility was less than 50 metres on both the runways, main (28/10) and third (29/11), airport sources said.
Around 130 domestic and international flights were delayed by over three to four hours after dense fog enveloped the airport and visibility become poor.
Also 20 domestic and international flights arriving were diverted to other cities as the visibility was less than 50 metres, which is the minimum required visibility for a flight to land using the most advanced Category III B (CAT-IIIB) of the instrument landing system.
According to sources, these flights were diverted as either their crew was not trained to operate in CAT-IIIB conditions or their aircraft were not CAT-IIIB compliant.
"This is in violation of clear cut instructions by the Director General of Civil Aviation to deploy CAT-IIIB compliant aircraft and pilots during the fog season," they said.
Smaller aircraft like turbo prop ATR, Canadian Regional Jets (CRJs) and Bombardier's Q400 turbo prop are not CAT-IIIB complaint, hence not fit to operate in dense fog conditions.
Eight flights coming to Delhi were diverted to Jaipur, Nagpur and Mumbai between 4am and 6am, when the runway visibility was less than 50 metres.
An Air India flight, coming from Frankfurt - a Dreamliner - was diverted to Mumbai as the aircraft and crew is not CAT-IIIB rated by the DGCA.
The fog started to descend at the airport around 8pm last night but it become dense from 11.30pm. The general visibility and the runway visibility worsened after 2.30am when it reduced to less than 50 metres.
A Royal Dutch Airline flight (KLM 872) to Amsterdam was delayed by over 20 hours due to fog and subsequent completion of flight duty time limitations (FDTL) of the crew.
The flight was cleared for take off at 2.30am but it had to return from taxiway due to some technical reasons. In the meantime fog enveloped the airport and the visibility dropped to less than 100 metres, and the flight was held up.
When visibility rose above the permissible limit, the FDTL of the crew ended and the flight was rescheduled for departure at 11.45pm, sources said, adding passengers have been accommodated in hotels.
Airport MeT incharge, RK Jenamani said that very dense fog had formed over IGI between 2.30am to 9.30am with runway visual range dropping to less than 50 metres on third runway and it was less than 175 metres on main runway which affected the flights badly.
He said the situation is likely to remain same on Monday night.