With recent stormy weather conditions and flights being diverted due to turbulence, let’s find out more about ‘turbulence’ and that phrase you may be hearing lots of – ‘Go Arounds’.

What is Turbulence?

Turbulence is a disruption in the air caused by a sudden change in airflow, which can cause a bumpy flight or, in the worst-case scenario, even crashes. Turbulence is rarely fatal nowadays as most aircrafts are designed and manufactured to withstand heavy turbulence. Between 2002 and 2017, 524 people were reportedly injured due to turbulence, as the Federal Aviation Administration reported.

 

Diagram showing turbulence ​© John Fraser / CBC
Diagram showing turbulence © John Fraser / CBC

What Causes Turbulence?

There are many different causes of turbulence, one of which is Wake Vortex Turbulence, which occurs in different extents in every flight. Wake Vortex Turbulence is caused by the disruption in the air generated by the aircraft itself. Two counter-rotating vortices form behind the plane, which can be particularly dangerous if planes fly close to each other.

Turbulence Intensity Range ​© John Fraser / CBC
Turbulence Intensity Range ​© John Fraser / CBC

Thermal turbulence is created by hot air rising from clouds. A Cumulonimbus cloud, or CB cloud, is a small cloud that continues to grow due to warm weather conditions. CB clouds can grow very large, with the energy inside the cloud being equivalent to 10 Hiroshima-sized atom bombs. As the clouds contain a lot of moisture, this can be picked up by the Weather Radar technology in the cockpit, which can clearly detect the CB clouds so that pilots can avoid flying inside of them.

Another type of turbulence is Mechanical Turbulence which is caused by friction between the air and ground. Disruption in the wind flow can result from mountainous terrain or even tall buildings.

However, the most common cause of turbulence is Jet Streams. They are powerful air currents, like tunnels of air, which can be several thousands of miles long and wide, with speeds reaching up to 250mph. Pilots try to avoid jet streams where possible by diverting the plane, which causes longer journey times and increases carbon emissions and jet fuel usage. There has been a 15% increase in vertical shear between 1979 and 2017, which is said to be caused by climate change.

 

Graph showing the increase in the amount of clear-air turbulence within the North Atlantic © Paul Williams / University of Reading
Graph showing the increase in the amount of clear-air turbulence within the North Atlantic © Paul Williams / University of Reading

Professor of Atmospheric Science in the Department of Meteorology at The University of Reading, Paul Williams, stated:

“The 15% shear increase must rank as one of the largest anthropogenic changes to have occurred in the climate system since satellite observations began. The change has been taking place silently, high above our heads, for the past 40 years, and it has gone unnoticed until now. It makes me wonder what else we don’t yet know about how climate change is altering the global atmospheric circulation.”

What is a Go Around?

A Go Around is when the pilot or air traffic control don’t deem it safe enough for the plane to land, so they divert and fly around nearby until conditions have improved. Go arounds are always performed due to safety and can be executed to prevent accidents and ensure a safe landing.

 

What is a Go Around? © Aerosavvy
What is a Go Around? © Aerosavvy

When is a Go Around Performed?

The need to perform a go around can be due to many different reasons, such as turbulence caused by the weather or miss calculations by air traffic control. The weather is the main factor a go around may be needed; for example, when landing, if the pilot cannot see the runway and approach lights due to fog or rain, they will have to execute a go around until it is safe enough to land. Wind can also affect the stabilisation of the plane. From about 500 feet above the runway, the pilot must decide whether they can safely land the aircraft.

Another reason a go around may be performed is if an aircraft enters the runway without prior confirmation. Air traffic control will pick up on this and radio to the pilot that they will have to go around until they can make necessary preparations for a safe landing.

 

There can also sometimes be miss calculations by air traffic control. If two aircrafts are scheduled to land on the same runaway too close to each other time-wise, air traffic control will ask the aircraft behind to go around to make sure there is enough room for both aircrafts to land within a safe distance.

On average, every pilot will have to perform a go around between 2-5 times per year. Would a go around on your flight cause you stress or relief that you’re in safe hands? Let us know in the comments below. 

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