Hot And High -- The Science Behind Unusually Long Runways In Some Airports

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I still remember quite vividly, it was January 21st 2012 at the O. R. Tambo International Airport in Johannesburg (That's like six years ago, how time flies) it wasn't my first time travelling by land, so as our aeroplane hit the runway at the airport and kept on running for some few more minutes on the runway (this was quite unusual), I began to imagine our aeroplane had developed an engine fault.. but then cut the whole story short, our aeroplane eventually came to a hault and we could all highlight. I was quite young as as the time of these event, so I inquired from my aunt when ingot home, the only explanation she could give to me then was: some airports are bigger than some, well as a child I was certified with her answer -- some airports are way bigger than some other airports; well maybe longer.

The years have rolled by, but the memory remains evergreen. About two weeks ago, I got caught up in a conversation with a air hostess, we talked alot about the industry where which she worked. These conversation got me asking so many question and over the next few articles, I would make an attempt at answering them. Early last week, I began a scientific inquiry to find out what brings about the marked differences in the length of airports runways in different countries of the world. It didn't take too long, I discovered that the particular airport which our aeroplane had landed on was Hot And High. Well, you might be wondering, what's Hot And High?!, well, same question I asked, after having read some litertures I got from a friend in the aviation industry, this is what I had gathered.

Hot and High -- What Is It All About?

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The phrase Hot and high is popularly used in the aviation industry to conote a condition of extremely high ambient temperature, as well as a high elevation of an airport. The condition of such airport has a very big impact on the flight of aeroplanes, and thus, it becomes a very serious cause of concern, this is because there significantly influence the safety of the aeroplanes which fly in such regions. Let's not get ourselves confused here, the term hot and high aren't really the same thing, they are more like two sides of the same coin. Let's take a closer look at them.

For hot, it signifies the current existing temperature of a particular region is high. Given the fact that temperature happens to be a variable physical quantity (its value continuously changes), the intensity of ‘hot and high’ conditions also experiences change. High on other hand, simply points us in the direction of the level of elevation of a particular airport. In these case, the land in which the airport is built plays a very important role, but you'd know that it's high once the land has more elevation as compared to the standard terrestrial heights -- okay, this is the best way I can explain it.

With the above explanation of what the phrase hot and highmeans, I believe we can put names of countries whose airports are hot and high (feel free to do so in the comment box), meanwhile here's a few:

• Denver International Airport (DIA) in Colorado and Siachen Glacier (India).

• Brasília–Presidente Juscelino Kubitschek International Airport in Brazil

• Canberra International Airport (CBR) in Australia

• Albuquerque International Sunport in New Mexico

The challenge

Having to work at an airport as a pilot was definitely one of the aspirations of a good number of my colleagues in the sciences way back secondary school, well some of them saw their aspirations turn into reality, while some didn't. During the course of my research, I have had reasons to ask: for pilots working in such airports which happen to experience such atmospheric conditions, could this pose a challenging task for them?! Well, the answer is yes.. but why is that?!

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Hot And High Takeoff. Image by Pepe.is.great via Wikicommons CC BY-SA 4.0</sub>

When we talk about hot and high, It basically has to do with air density. It is a known fact that air density decreases overtime with a complementary increase in the temperature of the immediate surrounding as well as its altitude. This is the point where the problem lies, as taking off or landing becomes particularly challenging. Decreased air density would ultimately result in a reduced lift generation by the wings of an aeroplane. Decreased air density would also disrupt the internal operation and performance of the engine of an aeroplane, these would ultimately put in peril the safety of such flight.

The Solution

Looking at the fact that Hot (hotness) and high (level of elevation of a given region) conditions are both conditions which cannot be altered by way of artificial means, one way of talking these problem would be to adopt some alternatives which can be artificially controlled, thus the need for longer runways in airports with hot and high conditions.

The most popular technique adopted at most hot and high airports is the making of very long, infact longer runways. The presence of longer runways increases the take off running distance of an aeroplane, thus supplying the much needed energy for an the aeroplane's subsequent climb. The reduction of the total weight of the aeroplanes would also be of added advantage, these could be done by taking out equipments which are so necessary on the aeroplane and pilots could also go round the destination in order to use up surplus oil, just to be left with the appropriate amount of oil to make a safe and successful landing.

Another option for handling hot and high airports is to carry out some structural changes in the aeroplane. These could be changing to more powerful engines, bigger wings, the injection of distilled water, additional high-lift devices, assisted take-offs etc. These would help guarantee smooth take-offs, successful landing as well as make up for hot and high atmospheric conditions.

The next time an aeroplane you are on is running on a runway which seems longer than usual, perhaps like it has no end, you don't need to be afraid -- just bear in mind that the airport likely has atmospheric conditions that's

Reference
_{Hot And High -- Wikipedia}

_{Hot and High Operations -- Skybary.aero}

_{Higher Temperatures Mean More Delays And Bigger Costs For The Airline Industry -- Forbes}

_{Why Is it Difficult For Airplanes to Land/Take Off When It’s Too Hot? -- Scienceabc}