When we rise in height in an aircraft, we cannot accurately predict what type of meteorological phenomena we are going to encounter on the way.
Despite the fact that most of the meteorological phenomena occur in the lower layers of the troposphere, between ground level and approximately six kilometers, and most commercial flights take place at its upper limit between 10 and 10 15 kilometers of altitude, the truth is that in every flight there is an ascent and a descent where the most meteorologically active layers are crossed. Despite everything, aviation is still the safest mode of transport today.
Next, we explain some of the phenomena that we can find and what risks they entail for the flight.
Storms are probably one of the most feared weather phenomena for air navigation. The clouds that make them up are called cumulonimbus, and their vertical formation depends on solar heating together with the presence of low temperatures in height and large amounts of water vapor.
Inside a Cumuloninbo there are strong upward and downward currents that cause extreme turbulence, to which hail, precipitation and electrical activity can be added. The enormous amounts of water that are kept in suspension inside the cloud give an idea of the enormous energy present, capable of disintegrating an airplane if it dared to penetrate inside. To get an idea of the enormous liquid mass that a storm represents, a Cumulonimbus with an altitude of 6 km, and a width and length of 1 km – that is, a 6 km cloud 3 – would contain 18,000,000 liters!
The storm formations are detected by the pilots by means of the meteorological radars equipped on board the aircraft, which provide information on the intensity and location of the storm, allowing the best air route to be planned to avoid the most active nuclei. Previously, the aeronautical meteorological reports -the METAR and the TAFOR- warn hours in advance of the possibility of encountering this type of phenomenon.
Passengers during the flight can have a feeling of proximity to the storm, since they can observe the cloudiness or the light of lightning, but in general the plane passes a great distance from these cloud formations so the flight is absolutely safe.
In the following video, we can see an example of the evolution of a storm and how the different traffics take into account their position to avoid it, and even how they wait at agreed points at times of greatest activity.
Lightning or electric shock
Statistically, every 1,000 hours of flight, lightning strikes an airplane. Therefore, this meteorological phenomenon is usually relatively common. Despite these data, lightning does not usually cause damage to the aircraft, since it acts as a “faraday box”, keeping its occupants safe.
Electric charges travel through the exterior structure without affecting the interior. Essential equipment such as the electrical, navigation or fuel system, for example, have extra protection for these cases. However, sometimes the discharge can overload the electrical circuits of the aircraft or cause damage to the fuselage, so after a lightning strike, the aircraft must undergo a review before making another flight.
As a curiosity, in 1980, NASA took off a plane during a storm in which the aircraft was hit by up to 72 lightning strikes in 45 minutes of flight. This provided them with a lot of information to combat and reverse the possible effects that this phenomenon could have.
Especially in colder countries, ice formation is one of the phenomena that pilots fear the most.
The ice on the plane is concentrated in the impact zones of the air. Wings, crystals or protruding parts of the aircraft fuselage such as antennas and probes. The accumulation of ice causes various negative effects on the aircraft, such as changes in the aerodynamics of the wings and tail or substantial increases in weight. Fortunately, modern airplanes have “anti frost” systems that allow hot air flows from the engines or electrical resistances under the most prone areas to prevent the formation of this dangerous flight companion.
Finally, concentrations of ice on the runway can cause problems in aircraft takeoffs and landings. Airports where this phenomenon is frequent have powerful anti-snow and anti-ice equipment, both to clean the runways and to “defrost” the plane with antifreeze products before taking the flight.
The phenomenon of shearing occurs at levels close to the ground, in conditions of marked atmospheric instability and with complicated orographies. For example, with storms in nearby areas and in mountainous areas.
Básicamente consiste en un cambio brusco de la dirección del viento en su sentido horizontal. El hecho de que suceda cerca del suelo hace que en muchos casos se produzca en momentos tan críticos como el aterrizaje, con el riesgo que conlleva. Un buen número de accidentes sucedidos en los minutos finales del vuelo se deben precisamente a la presencia de éste indeseable fenómeno.
The air loses density as it warms up. In other words, hot air is less dense than cold air. This circumstance limits the operation of airplanes in very hot environments. To achieve a relative speed with respect to the air they will need to reach a higher speed on the ground and travel a greater length of track. Also, the higher the altitude, the lower the density. Both circumstances together – altitude and high temperatures – seriously compromise the air operation.
To avoid this circumstance there are conversion tables. From the temperature, altitude and weight data of the aircraft, they allow to determine the length of the runway necessary for take-off or whether or not it is possible to take off on a given runway. As a curious note, in Mexico City, whose airport is located 2,230 mts. (7,316 feet) altitude. In summer, the takeoff of large aircraft such as B747, B777 or A380 are prohibited during the day and are limited to night hours, since at night the colder air facilitates the operation.
A frequent occurrence is the impact of birds with aircraft. How common is this incident? You can see it in detail in this article.
In another article we will deal with more meteorological phenomena, such as low visibility or fog that also affect aircraft flights.