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Why flying in and out of Delhi in winter is such a bother

Why is it that airlines, pilots and the Delhi airport have not been able to crack the chronic problem of beating fog conditions the way many international airports are able to, some of them in places that experience more extreme weather conditions?

columns Updated: Jan 17, 2016 00:48 IST
Sanjoy Narayan
Why is it that airlines, pilots and the Delhi airport have not been able to crack the chronic problem of beating fog conditions the way many international airports are able to, some of them in places that experience more extreme weather conditions?
Why is it that airlines, pilots and the Delhi airport have not been able to crack the chronic problem of beating fog conditions the way many international airports are able to, some of them in places that experience more extreme weather conditions?(Vipin Kumar/HT File Photo)

Everyone has an anecdote about the ordeal of flying in and out of Delhi during the winter months. My favourite is one that a colleague told me. It was December 31, 2006. President Pranab Mukherjee, then foreign minister in the UPA-I government, was taking an Air India flight back to Delhi from Kolkata. As the aircraft entered Delhi’s airspace, the pilot announced that there was a queue for landing and that he’d give an update in the next few minutes. But the next announcement surprised everyone because the pilot said thick fog had suddenly rolled in and he couldn’t land. They’d be going back to Kolkata. My colleague, who was also on the same flight, remembers a Congressman who was part of Mukherjee’s entourage telling him while alighting at Kolkata airport that the party’s local leaders would curse him no end because all their plans for New Year’s eve revelry were now dashed as the minister would be back in town.

The collateral impact of a senior party leader not making it back to Delhi and thus spoiling the fun may be amusing but the winter ordeal that air travellers face annually when they want to go to and from Delhi often isn’t. On many winter days, between late December and mid-January, because of heavy fog conditions, aircraft are unable to land or take off from Delhi. This leads to delays, diversions, cancelled flights and irate customers (disclaimer: last week, I was a victim; a cancelled flight made me wait five hours in a depressing airport). Why is it that airlines, pilots and the Delhi airport have not been able to crack the chronic problem of beating fog conditions the way many international airports are able to, some of them in places that experience more extreme weather conditions?

First, the technology. Pilots deploy what is known as an Instrument Landing System (ILS) to land in low-visibility conditions. There are different categories of ILS, starting with CAT I, which allows planes to land when the runway visual range is not less than 550 metres (that is, in a relatively clear and normal situation) to CAT II (visual range not less than 330 metres), CAT IIIA (not less than 175 metres), CAT IIIB (when visual range is down to 50 metres) and CAT IIIC (when visibility is near zero). In Delhi’s winter months, fog often reduces visibility to 50 to 175 metres, which requires aircraft to deploy CAT IIIB to land or take off. But to operate the CAT III system, pilots need to be specially trained. Not all are.

Official spokespersons for airlines insist that most of their pilots are adequately trained but that is not so. In the larger airlines, 50-60% of the pilots are CAT III trained; in smaller airlines, it is much less. To operate landing or takeoff operations using the CAT III system, both, the pilot and his co-pilot, have to be appropriately trained but often a perfect combination is unavailable. Also, because training for CAT III doesn’t come free — it’s around $2500 (Rs 1.70 lakh) per pilot plus periodic upgrades — some airlines tend to limit the number of CAT III trained pilots. One airline official candidly said that since low-visibility conditions occurred only for about two weeks and that too mainly in Delhi and some northern airports, it wasn’t cost-effective to train hundreds of pilots.

Airlines have other arguments too. Delhi’s fog conditions are unpredictable, they say, with the Met office often unable to predict sudden changes. And, since airlines roster pilots in and out of Delhi based on forecasts by the Met office, if fog isn’t expected CAT III trained crew is not deployed. Then if fog rolled in suddenly, landings and takeoffs would have to be aborted. Moreover, high pollution levels, particularly smoke, can make visibility poorer, often dropping down to below 50 metres on the runway — to levels where CAT IIIC, which Indian pilots aren’t trained in, has to be deployed.

Landing aircraft in low visibility is demanding — requiring a complex complementarity of equipment (both onboard and on the ground) and human skills (of pilots who have to make decisions in seconds as well as those in charge of air traffic control). All the more reason why airlines should not balk at training more pilots.

The author is the editor-in-chief of Hindustan Times. He tweets as @sanjoynarayan.