Uno de los fenómenos más reseñables en cualquier vuelo es la aparición de turbulencias, aunque raramente supone un riesgo para la integridad de la aeronave o de los pasajeros.
In conversations with pilots, flight instructors and the odd human behaviouralist, it often comes up that one of the most recurrent fears of some people about flying is turbulence.
The definition of turbulence is simple. It is a agitation of air produced by the action of some forces in its environment. They could be visualised as swirls of air that behave in a chaotic, erratic and capricious manner. Their consequences on the flight of an aircraft are changes in attitude and altitude which cause everything from small, often imperceptible tremors to severe turbulence, requiring all passengers to take their seats, fasten their seat belts and follow the crew's recommendations.
In spite of the spectacular nature of these phenomena, they are generally do not pose any risk to the safety of the aircraft. In the event of severe turbulence, the crew will normally choose to reduce the speed of the aircraft, change altitude or, if necessary, even request a reroute.
Under normal conditions, air tends to flow in overlapping sub-horizontal sheets in any layer of the atmosphere. Its agitation occurs equally at all levels, from the ground to well above the cruising altitude usually shared by commercial aircraft.
There are various types and origins of turbulence, but the most common turbulence experienced by aircraft in flight usually has three causes: mountains, jet streams and storms.
When it comes to mountainsThe air behaves like waves on the sea when they reach a beach. They are sheets of fluid that tend to move on top of each other, but that adapt to the physiognomy of the terrain and adopt different behaviours.
Some of this air passes smoothly over the mountains and continues to move forward. Other sheets of air, however, pile up against the mountains themselves and have no choice but to rise, generating "waves", which can propagate in the atmosphere as broad, gentle oscillations, but which can also break up and become many tumultuous currents, which we experience as turbulence.
The jet streamsare huge, fast-moving air flows that generally circulate near the tropopause, at the top of the troposphere (between 8,000 and 15,000 metres). The most important are located in polar (60° in northern and southern latitudes) and subtropical areas, forming when large masses of cold air and warm air meet.. Winds blow from west to east at speeds ranging from 130 to 225 kilometres per hour, although they can sometimes reach 400 km/h.
Disorderly air (turbulence) associated with jet streams is caused by differences in wind speeds as an aircraft moves away from regions of maximum wind speed. The deceleration of winds creates areas of shear, which are prone to turbulence.
It is these types of currents that are often at the origin of the so-called "currents of the future".clear air turbulence"These are invisible, unpredictable and more common during the first hours of the day, resulting in small jolts in the aircraft.
The stormsThe third common factor in the generation of turbulence in flight is the formation of vertical cloud formations (especially cumulonimbus clouds) and sudden pressure changes. Vertical cloud formations (especially cumulonimbus clouds) and sudden pressure changes are breeding grounds for turbulence. It has also recently been concluded that thunderstorms not only generate turbulence in their immediate surroundings, but also can shake the sky also in more distant areas. This is due to the creation of waves caused by rapid cloud growth or very strong convective heating, which can cause turbulence up to hundreds of kilometres away.
Regardless of the origin of the turbulence, the most frequently asked question by passengers in relation to turbulence is often about el riesgo que supone para la seguridad de los vuelos.
Let us assume that turbulence alone will not bring down an aircraftunless coupled with human failure, a previous structural problem of the aircraft or the concurrence of other atmospheric phenomena.
The aircraft is itself resistant to turbulence, thanks in particular to the flexibility of the wings. que, a su vez, actúan junto al fuselaje como un cajón de torsión. En función del modelo de aeronave, la punta de las alas puede oscilar incluso más de un metro hacia arriba y hacia abajo. El ala es, además, uno de los componentes que más ha evolucionado técnicamente desde el inicio de la aviación, siendo su flexibility one of the key aspects in the improvement process. In addition to compensating for the weight of the aircraft and maintaining flight, one of its most important tasks is to ensure responsiveness to these unforeseen phenomena.
Prediction is one of the keys to minimising the impact of turbulence on flights.. Weather forecasts and pilot reports are useful for avoiding the areas where they occur, but they are relatively unreliable tools on a case-by-case basis. In the case of forecasts, the scale of the weather models is much larger than that of the aircraft flight, so that medium and small turbulence can go unnoticed. In the case of pilot reports, the problem often lies in the lack of accuracy in their localisation, although they at least detect the existence of the phenomenon in a certain area.
For the past decade, work has been carried out on the real-time forecasting modelsbased on the constant acquisition of data from sensors on the aircraft itself. Based on data on ground speed, wind speed, atmospheric pressure, roll angle and other parameters, the algorithm generates a turbulence event warning shared every few seconds. This information significantly reinforces weather forecasts and models, providing much more accurate information to pilots, giving them the possibility to take preventive action.
The field of turbulence prediction is important for airlines because of the relief for passengers to enjoy a "calmer" flight, but also because of the costs associated with turbulence. 600 million per year worldwide (extra fuel costs, insurance, damage to passengers, delays, etc.) have been estimated as a result of turbulence. Changes in altitude or flight routing also entail additional environmental costs due to additional fuel expenditure (and consequent emissions), which is in any case undesirable.
It is clear that nobody (companies, pilots, passengers...) wants to encounter turbulence during a flight, but, even if this were the case, we should be reassured because technology plays in our favour both in terms of prediction and in the aircraft's response. In this case, if you look out of the window and see that the wings are bending, it means that there is turbulence and the wings are playing their part.
In that case, continue to enjoy your flight... with your seatbelt fastened.
