Flight Plan

How flying weathers it all

Ashwini Phadnis | Updated on July 23, 2019 Published on July 23, 2019

What challenges do pilots face during adverse weather conditions? Ashwini Phadnis sounds out people on the job

Flying has a strong relationship with weather. In winter, it is fog in North India that poses a challenge to flights. Come summer, temperatures soar, and once the monsoon hits, rains play spoilsport.

Recently, the main runway in Mumbai, one of the busiest airports in India, was unoperational for over three days as an aircraft overshot the runway and was stuck in mud. There were also incidents involving an Air India Express aircraft going off the runway in Mangalore and getting bogged down.

But nervous flyers can take heart. According to Captain PP Singh, Senior Vice-President, JetLite, pilots are trained to deal with extreme weather conditions, including rain and fog, and snow in winter. He explains, “There are two major concerns for a pilot in rain. One is visibility, especially from the flight deck. Second is runway conditions because the runway becomes slippery. It is like a car. If you apply the brakes in the rainy season, because of less friction, it takes a car longer to stop. The system is the same for a plane.”

The cockpit windows have wipers but with rain falling and some wind hitting the aircraft as it comes in to land, the wipers are not very effective. Also, pilots see the runway lights through a film of water, which could give them a slightly different perspective.

“Then there is the issue of the speed at which the aircraft is coming in to land, especially in rain. To make an absolutely safe landing, the aircraft should touch down at the correct point, which is typically the first 3,000 feet of the runway. If the aircraft keeps floating and touches down further with extra speed, the plane does not want to touch down, it wants to float, it wants to keep flying,” explains Captain Singh.

Commenting on the relationship between weather and flying, another pilot says that meteorology goes hand in hand with aviation as “you are flying in the atmosphere and all the weather phenomena are in the troposphere, which is the lowest layer of the atmosphere, so you are constantly exposed.” Hence, it is not only rainy conditions, but other disruptions to normal weather, like snowstorms, cyclones and volcanic eruptions, that affect flights too. And, believe it or not, so do very high temperatures.

Visibility challenges

Visibility during fog is a major issue and airlines are asked to ensure that they allow only pilots who are trained to land in low visibility to operate during mid-December to February in North India as weather tends to worsen rapidly. “When we take off for Delhi, the weather is fine for doing a landing in winter. But because of changing weather patterns it changes rapidly and by the time we approach Delhi, visibility has declined considerably,” says the pilot of a private airline.

Snow brings its own issues. For example, in various parts of the world, it is not uncommon for aircraft to be sprayed with hot water at a high speed to melt the snow which might have settled on an aircraft waiting to take off. Snow gives additional weight to the aircraft leading to more fuel being burnt.

However, pilots are quick to point out that extra planning helps ensure that flights do not encounter trouble in the winter months. Hence, in December and January, when it is known that there will be fog in North India, the route planning and timing are done well in advance. “Similarly, in the US, we know that there are going to be snowstorms on the eastern seaboard. Towards the East, when you go into Hong Kong and other places, you know there will be cyclonic activities. We keep a tab and inform the crew or re-route our flights accordingly,” says a pilot.

Experience counts as pilots plan for alternative destinations to beat bad weather. “Say, you are going to New York but during snowstorms you might want to have Chicago or Toronto as an alternative because if New York is affected, even Newark (another airport in New York) may be impacted. But the chances are, Toronto might not be affected,” explains a pilot.

Pilots also plan for flying in volcanic and cyclonic conditions. According to them, there are no constant fixed zones that they avoid although they definitely steer clear of areas where there is known volcanic, cyclonic or monsoon activity.

Pilots point out that they need to be careful while flying in the Indonesian airspace, given the amount of volcanic activity there.

Temperatures too help a smooth flight. According to pilots, the higher you fly, the better it is because the higher you are, the lower the temperature.

Says an Air India pilot, “Efficiency keeps going down with higher temperature. That is why, with jet engines, the higher you are, the better you fly, because it is cold and the air is thick. Besides, winds also make a difference but, by and large, it is outside temperature and weight that make a difference, which give you an optimal altitude.”

Published on July 23, 2019
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