Why planes became heavier and take-offs more difficult – What is true in Greece

If you miss a flight in the future, the weight of the plane might be to blame. Certainly not yours or the one in your suitcase. “Global stilling” worries airlines.

Christos Barounis

The main – worrying – element of Climate Change, which also coincides with humanity’s biggest challenge for the next 30 years, is the increase in global temperature. We are called upon to keep it well below +2 degrees Celsius by 2050, a goal that seems particularly difficult, perhaps even unattainable, when you consider that the temperature has already increased by 1.2 degrees and factor in the effects of the latest energy developments to the climate goals.

The effects of this phenomenon are so many, and such, that sometimes, a reference to the different sectors they “touch” is enough to understand the seriousness of the situation. So let’s take an example that, until today, you might not have imagined.

Airplanes and weight on takeoffs

Rising global temperatures are making it harder for planes to take off at some airports, presenting a new challenge to aviation. The more frequent the heatwaves become, the more the problem could spread to more and more flights, forcing airlines to even leave passengers on the ground.

The reason; “The main challenge any aircraft faces as it takes off comes from the fact that planes are very heavy and gravity wants to keep them on the ground,” says Paul Williams, Professor of Atmospheric Science at the University of Reading in the UK, adding:

“To overcome gravity, they have to create lift, where the atmosphere pushes the plane up.”

But what does lift depend on? “It’s a number of factors,” Williams tells CNN, with one of the most important being “the temperature of the air. As the air warms, there are fewer molecules available to push the plane up.”

Airplanes have 1% less lift for every 3 degrees Celsius increase in temperature, according to the professor, who explained that “this is why extreme heat makes it harder for airplanes to take off. In some really extreme conditions, they can actually are impossible”.

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The problem mainly affects airports at high altitude, where the air is already thinner, and those with short runways, as they give the plane less room to accelerate.

According to Williams, if a plane requires 6,500 feet (1,981 meters) of runway at 20 degrees Celsius, that means at 40 degrees it would require almost 2.5 kilometers of runway to take off.

The example of Greece and the phenomenon of “Global stilling”

Williams’ research team began processing data from 10 airports in Greece. Why did they choose Greece? The reasons are understandable. Because the country stands out for its high temperatures, as well as for the short runways of its airports.

So they found that there was a temperature increase of 0.75 degrees Celsius per decade from 1970 onwards. What else did they find? “A decrease in cross-runway headwinds of 2.3 knots per decade, which is considered beneficial for takeoffs, creating evidence that climate change is causing what we call ‘global stilling’, which explains why there is a slowing down of the winds.”

The research team used this temperature and wind data, feeding it into a take-off performance calculation system for a wide range of planes, including the Airbus A320, which is one of the most popular in the world.

“What we found was that the maximum take-off weight is decreasing by 127kg every year, which is the equivalent of one passenger plus their suitcase,” Williams explained. What does he mean; How based on these data, every year, one passenger would have to be left out of the aircraft, in order to balance the required weight!

From its launch in 1988 until 2017, the A320 saw its maximum take-off weight reduced by more than three tonnes at Chios Airport, which was also the main airport under the study’s “microscope”, with a runway length of less than 1,500 meters .

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A similar example is the “City” of London, which also has a corridor less than 1.5 kilometers long. It is typical that, during a heat wave in 2018, more than 12 flights had to leave some passengers (up to 20) on the ground in order to take off safely.

Accordingly, in 2017, dozens of flights were canceled entirely within days at Phoenix’s Sky Harbor International Airport as temperatures reached 48.8 Celsius, above the maximum operating temperature for many passenger planes.

Are there solutions?

Although the above figures cause legitimate concern for airlines, and many for passengers, especially those who travel frequently, it seems that there are solutions.

Williams confirmed this, saying that “for example, we could schedule departures at times of the day that are not so warm, with most of them being early morning and late evening.” This tactic, after all, is already used in areas such as the Middle East.

At the same time, manufacturers such as Boeing have already turned to the “hot and high” option for airports located at high altitudes and for takeoffs that become hot. This option provides extra thrust and larger airfoils to compensate for the loss of lift and low air density.

Another good and logical solution would of course be to lengthen the runways, although this may not be possible at all airports.

As a last resort, however, it could be reduced passenger numbers, although, according to Williams, this is likely to be a rare occurrence as “most planes are never at maximum take-off weight”, so it could happen. in borderline cases and mainly at airports with very short runways.

In any case, climate change brings an additional challenge to the industry which, “while not a headache at the moment, based on the evidence “could make it difficult for us in the future”.

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