What Is Turbulence?

Thomas Cook Airlines plane

We asked one of our pilots to explain turbulence, what it is and why it happens.

A lot of people who have a fear of flying, put some of it down to the turbulence experienced while onboard.  In order to start addressing these fears it’s important to understand what turbulence actually is.

This article has been taken out of the Thomas Cook Holiday Report, find out more about the report here: The Thomas Cook Holiday Report 2018


So, what is turbulence?

The air is a fluid, just like water. If we imagine a nice still lake with a rowing boat on it, that is similar to flying through still calm air. Now, if we imagine the same boat on the river rapids at your local theme park, this is the same as turbulence – the choppy water or air is caused by turbulent non laminar flow beneath the surface. It is absolutely nothing to worry about; the aircraft is still flying forward at nearly 500mph, albeit over some small speed bumps!


Do we have to turn off our electronic devices for take-off and landing? Why is it ok to have them on during the flight?

The number of mobile phones and electrical devices has increased exponentially over the last few decades. There is now such a cross section of devices that it is impossible to assess the impact of every device on the aircraft. Therefore for most airlines, a general restriction on all electronic devices during take-off and landing – the most critical parts of the flight – ensures the highest levels of safety.


You have two pilots, what does the one not flying do?

When we fly, the captain has ultimate responsibility for the flight. However we share the flying so one pilot will act as what we call “pilot flying”, and will fly the aircraft, while the other pilot will act as “pilot monitoring” and will primarily monitor the other pilot, as well as talk on the radio and complete any paperwork. Prior to take off, the pilot monitoring will walk around the aircraft to check the fuelling and loading along with inspecting the exterior. The pilot flying will ensure everything is ready to go and program the flight management computer with the route and performance figures.

Thomas Cook Airlines Pilots


Why do you dim the lights for take-off and landing?

By dimming the lights, all of our eyes, pilots and cabin crew, can adjust to the dark for a better awareness of what is going on outside as we prepare for take-off and landing. In the unlikely case of an emergency landing, the lighting available during the evacuation may be greatly reduced. Reducing the aircraft lighting for a short period before landing allows time for the human eye to adjust to low light levels.

How much do you use autopilot and when do you use it vs. not using it?

It really depends on a number of factors, including weather, route, airspace and distance of the flight overall. Significant attention is required to fly an aircraft and autopilot is there for pilots to use when brainpower and attention can be focused on monitoring of conditions such as weather changes, turbulence and fuel performance.

How much do you talk to Air Traffic Control (ATC) on an average flight? Do you ever have small talk?

The radio chatter with air traffic depends on the airspace. We talk to ATC a lot over land. The closer the aircraft is to land, and the more planes in the vicinity, the more we talk to ATC. It is extremely rare to have any small talk with ATC, but we do get asked for feedback on clouds and turbulence. Over the ocean we rely on a form of ‘text messaging’ via satellite for ATC, as it is much more reliable and faster. Small talk is generally discouraged especially when the frequency is busy, but at quiet times there is sometimes the odd comment or hello to a familiar voice.

More on turbulence below from Captain David our resident MasterChef finalist!

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