For the operator, aircraft seating configuration is very deliberate. It depends mainly on aircraft size, class mix (how large first class is, if it exists at all), and business model. For you and I on the the other hand, we care about price and comfort, legroom, seat width, and the view. Only one of these three items comes “free” and that is the view from a window seat.

Are you an aisle guy or window girl?

I mean, it’s either one of the options above or the middle seat, and I have not met anyone who is tickled to be there. In the end it all boils down to preference; even the window seat isn’t all that it’s cracked up to be. I’m certain at least one person would agree on this: Christ Kurylo, a passenger who was injured when a propeller crashed through the window of a Bombardier Q-400 in 2014.

I bet Christina would feel differently about flying but propellers don’t come flying off on their own accord either. This was an incredibly rare occurrence and luckily she survived it.

 


 

Now try to get that last image out of your mind by picturing a beautiful white bird gliding peacefully through the sky with eyes closed and wings spread out in majesty. Whooosahhh. Ok

Tell me this, do you jostle to get the window seat when you’re booking a flight so you can stare into the sky as the aircraft climbs and cuts through clouds? Does it get you excited to see the world go by as your aircraft flies at subsonic speeds, while you coast along enjoying magnificent views of the oceans and incredible landscape patterns when the skies are clear enough? You can thank the tiny breather hole in the bottom of your window for this one, as it prevents it from fogging up among other more critical functions.

 

Airplane window breather hole bleed hole with wing blue sky

Do you like to watch the landing gear retract into the wheel-well while the wheels are still spinning after takeoff? If your answers are yes to these questions, then you my friend, are in good company. I always try to book a window seat just so I can peer out and marvel at the world. I am definitely not one of “those” notorious for taking videos hoping to capture something interesting, but not life threatening on film.

Have you ever sat by the window on an airplane and wondered why they were oval shaped instead of square or rectangular like you are probably accustomed to everywhere else? The window in your bedroom is most likely square in shape, and even the windows logo on your Microsoft powered laptop is square shaped. We are more likely to draw a square in representing a window. So how come the window on every aircraft is either a circle or oval shaped? The answer lies in the series of problems and solutions that plagued the aviation industry in the past.

The Second World War brought a rapid growth in technology. Before the war, civil aviation was mainly for the elite and the aircraft couldn’t fly at very high altitudes. However, with the increasing need to fly longer with more passengers during the war, cabin pressurization was introduced. This allowed the aircraft fly upwards of 20,000 ft while maintaining a cabin altitude of 6,000 ft. This meant that while the aircraft could fly faster, burn less fuel, and face less turbulence, the passengers would not feel the effects of flying at such altitudes such as hypoxia. Also, during the war, technological improvements in the design of engines meant that they had more pounds of thrust produced to power larger aircraft sizes.


These helped in the design and the production of the first commercial jet airliner, the De Havilland Comet, which featured powerful engines, a pressurized cabin and large square windows. Up until this time, pressurization cycles (one cycle consists of a depressurized aircraft being pressurized for flight and depressurized on landing again) weren’t fully understood by aircraft designers and the means to properly preform stress tests were limited. Three successive crashes of the Comet brought about an aircraft accident investigation into the crashes. The investigators found that cracks had appeared around the doors and the windows of the aircraft due to pressurization cycles and that had led to the aircraft blowing up mid air.

 

Why had the cracks started at the windows and doors? Because at the edges of the square door and windows, there was concentration of stress. This can be explained using high heel shoes that ladies wear. Imagine a person weighing 50kg wearing high heel wedges stepping on you. Now imagine the same person wearing stilettos of the same height as the wedges stepping on you. The pain you’ll feel from both incidents will be different despite the constant weight of the person and the height of the heel. The difference is in the concentration of stress; while the individual wearing the wedges had the weight distributed along the sole of the shoe, the one with the stilettos had all the weight concentrated at the sharp point of the heel which made it more piercing. The same goes for the square windows. The stress the fuselage of the aircraft underwent during the pressurization cycles was concentrated at the sharp pointed edges of the squares which forced a crack in the fuselage structure at those points.  

These cracks were further propagated as the aircraft continued to go through the stresses of the pressurization cycles.
If you then imagine an aircraft fuselage under immense pressure with a crack or an outlet for all that pressure to escape through, what you have were the three successive accidents that happened. This led to the redesign of the windows and doors and putting in measures to stop the propagation of cracks while the aircraft is pressurized. Unfortunately, these changes came at the cost of several lives.


My lecturer in school always said that “the history of aviation was written with the blood of men”. This much is true.

So next time you peer out of the windows while flying to your next destination, even though you might be adjusting to wearing a safety mask, you will now notice and appreciate the little unnoticeable designs improvements of the windows and the history behind them.

I hope this causes you to reach for the skies in your own life.

Aviation Safety Specialist, James Adegboye – Author

Reference 1
Methodology platform for prediction of damage events for self-sensing aerospace panels subjected to real loading conditions – Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Wreckage-of-G-ALYP-one-of-the-Comets-that-exploded-mid-air-showing-the-fatigue-cracks_fig1_305881922 [accessed 30 Jun, 2020]