Most of us consider ourselves to be pretty savvy travelers. We check-in for our flight online so as to avoid the ticket counter at the airport and know exactly what to do in order to expedite our time in the TSA Security lines. We also download our boarding passes onto our phones so we’ve got one less piece to paper to worry about and we very often entertain ourselves with music or downloaded content on our phones or tablets so we’re not dependent upon the airline for entertainment. But how much do we really know about what goes on during our flight? If you’re focused on your devices, reading or chatting with a companion, sleeping or just daydreaming out the window, you’re not alone. Most of us fly often enough for the journey to be commonplace, perhaps even mundane. But there's probably a lot we don't know, so here are a number of interesting facts about flying that might even take you by surprise.
Why is There a Hole in My Window?
Some folks swear by the window seat, watching the world go by through a rather small rectangular opening in the fuselage. Next time you’re sitting there, take a closer look at the bottom of the window and you’ll notice a small hole. What's it doing there? It all comes down to pressure: the higher the altitude, the lower the oxygen, which can leave people short of breath and perhaps even feeling ill. At a cruising altitude of 35,000 feet, the air pressure is so low that anyone would pass out if
exposed to it, so a plane's cabin must be pressurized to be much greater than the outside air. But, the plane needs a way to release some of the strain this puts on the aircraft. Enter the tiny "bleed" or "breather" holes which does just that. Look closely at your window and you'll see that it's not composed of simply one durable pane, but three. According to Mark Vanhoenacker, a British Airways pilot who writes for Slate, the innermost pane primarily exists to protect the second and third panes, which are "designed to contain this difference in pressure between the cabin and the sky." The bleed hole, then, allows pressure to be balanced out between the cabin and the gap between the panes. Another function of the airplane window hole is to release moisture and prevent frost or condensation from misting up so you can appreciate the view and take those great photos for your next Instagram post.
Why Dimming the Lights Is Important
In all aspects of commercial aviation, the safety of passengers and crew members is paramount. As such, it’s perhaps not surprising that safety is the primary reason that cabin lights are dimmed shortly before takeoff and landing procedures.
The lighting is dimmed for the same reason that crew members ask passengers to raise their window shades, namely for safety. In the event of an emergency, good visibility can make a crucial difference to one’s safety. “You want your eyes acclimated,” says Jon Lewis, a senior pilot with a major US airline. “During nighttime takeoffs and landings, you dim the lights so that you have some night vision going on.” It can take our eyes between ten and thirty minutes to fully adjust to a dark setting, which means that dimming the lights can help the eyes pre-adjust to lower light. And if it’s night when everyone must suddenly evacuate, those several seconds it takes for your eyes to calibrate to low-light conditions can be precious, and can make all the difference in safely exiting the aircraft. In dimmer light, emergency lighting and illuminated pathways will also be more visible to passengers.
Why Does My Food Taste Different?
Although aircraft generally cruise at altitudes near 35,000 feet, air pressure in the cabin is about 6,000 to 8,000 feet above sea level, making it difficult to prepare fresh meals onboard. So, airlines freeze pre-cooked meals on the ground and thaw them out while airborne. Meals are also prepared in advance so they’ll be shelf-stable for a number of hours. Then they’re reheated in less than ideal conditions. While domestic economy class meals disappeared a number of years ago, meals are still served on most international flights. Airlines came to understand that by the time they served hundreds of passengers, the food would either get cold or dry. Their solution was to douse whatever they were serving in sauces or gravy. But even when airplane food is made in a way that might taste good before the flight takes off, the combination of dry air, low pressure, and loud engine noises during flight heavily impact passengers’ ability to smell and taste — causing even the best-prepared food to seem slightly off. The dry air in the cabin also tends to suppress our sense of smell, which is an important factor in taste. Low air pressure and background noises further impact the way we taste, by repressing the ability to taste sweet and salty foods. For meals to taste the same in the air as on the ground, airline caterers have to add up to 30 per cent more sugar or salt to our meals.
Where Does the Waste Water Go?
It’s a myth that airplane toilets empty into the atmosphere on purpose. For a long time, however, they were little more than airborne port-a-potties. They used electric pumps to circulate a chemical deodorizer called Anotec throughout the system to break down solid waste and keep things smelling tolerable. But, flying with large quantities of heavy fluids was expensive and ‘70s era, vintage “blue juice” toilets were notorious for seepage. Their internal valves were prone to leaks that could send wastewater onto the plane’s exterior. At altitude, that mix froze, creating that notorious menace known as “blue ice.” During the plane’s descent, the ice broke off from the plane and, only on occasion, did it actually make contact with the surface. Most of these archaic plumbing systems have been phased out of modern aircraft. Today, you’re probably sharing a cabin with what’s called a vacuum toilet. They’re a huge improvement over the old "blue juice" rigs and they’ve been standard issue on commercial aircraft since Boeing adopted them in 1982. There hasn’t been much innovation in the field since then, mainly because the technology works so well. They only use a fraction of the blue sanitation liquid they used to, and use a vacuum system to siphon waste into a tank rather than leaving the work to gravity.
Why Put Our Phones in Airplane Mode?
I’ve got some good news for you. If you ever see a fellow passenger sneakily using their cell phone after takeoff, you’re not going to fall out of the sky. In fact, the requirement to switch your phone to airplane mode has more to do with reducing interference and the associated distractions it might create on the flight deck, rather than any significant physical risk to the aircraft. In short, your phone tries to communicate with cell towers on the ground and, the more distant they are, the stronger the signal needs to be. Some say that’s not so good when we’re so near to a plane’s sensitive navigation equipment and, though the evidence is inconclusive, no-one wants to be proven wrong. Nevertheless, if the airline says so, you can enable Wi-fi or Bluetooth connectivity while remaining in airplane mode. Since 2013, the US Federal Aviation Administration has permitted the use of personal electronic devices onboard. So, can you make a call or not? Well, that depends upon your carrier. The US Federal Communications Commission announced in December 2020 that it had no plans to overturn its ban on in-flight cell phone calls on US airlines. However, the European Aviation Safety Agency legalized the use of phones during flight in 2014 and some airlines, like Emirates, have allowed in-flight calls for even longer. Whether your fellow passengers want to listen to your chit-chat, however, is an entirely different matter.
What Happens if Someone Dies in Flight
A medical emergency occurs in the skies about once every six hundred flights, according to a study appearing in the New England Journal of Medicine. The most common maladies are fainting, respiratory issues, heart trouble, nausea, or vomiting. The study found that it’s rare for an in-flight emergency to end in death but the worst-case scenario does occur about 0.3 per cent of the time. What happens next? Fortunately, carriers have come up with protocols that adhere to non-binding guidelines devised by the International Air Transport Association, an industry trade group representing the world’s airlines. In the event of a passenger death, notifying the cockpit will be flight attendants’ top priority so the captain can alert the destination airport and prepare the proper authorities to meet the flight upon landing. An emergency landing is not required. In fact, it’s highly unlikely and wouldn’t help any way. Once the aircraft lands, the body and anyone traveling with the deceased stay in place while other passengers disembark. At that point, medical professionals and airport authorities take over.
I hope this post has helped to better explain the "why" of what goes on at 35,000 feet and provided a behind-the-scenes glimpse for you into the fascinating world of aviation.
Until next time…safe travels.
Another very interesting post! Thanks, George.
Oh my goodness, what an interesting post. So many questions I didn’t really think I had. So many answers to accepted practices that I think we all take for granted. Thank you once again George for enlightening us!!