Why Planes Don’t Fly Higher – So you like to fly? Well, the average cruising altitude of a commercial airplane is between 31,000 and 38,000 ft. At this altitude, the air becomes thinner. As a result, aircraft can travel more easily and, even more importantly, burn less fuel. So, can’t modern planes rise even higher than that? Or even fly to space? The answer is a firm “nope”
But before I get into details, let me bring home several crucial points. As soon as a large jet takes off from an airport, the first thing pilots do is take the plane as high as possible, as fast as they can. Few people know that the average passenger airplane usually reaches its cruising altitude of 6 to 7 miles in the first 10 minutes of the flight.
On the other hand, each airplane has its own optimum cruising altitude, which is based on its weight and some other characteristics. For example, the famous supersonic passenger airliner Concorde, whose maximum speed was twice as fast as the speed of sound, used to fly way higher than other modern-day planes, at 50,000 to 60,000 ft.
But it’s the exception rather than the rule. Anyway, by flying at a height of 35,000 ft, planes manage to avoid bad weather, such as high winds and heavy rains, raging in the lower layers of the atmosphere. Also, such altitudes allow planes to avoid heavy airborne traffic, including helicopters and light aircraft; as well as to stay clear of birds and even big insects.
And finally, if an emergency happens at a height of more than 6 miles up in the air,pilots will have more time to get their ducks in a row and figure out the best possible solution. And now, let’s get back to the question, “Why can’t common commercial airliners fly higher than 38,000 ft?” Surprise, they actually can! But in this case, serious safety issues would arise.
First of all, while flying higher, a plane needs more time to get back to a safe altitude. And during an emergency like rapid decompression, every second counts. Secondly, flying at such a great height, aircraft can’t communicate with the ground services as efficiently as at the usual cruising altitude. Besides, the higher you get, the thinner the air becomes.
Eventually, if a plane climbs too high up, the air gets too thin to provide enough lift to keep the machine up. The thing is that the difference in air pressure creates the necessary lift. And if the altitude is too high, this difference is almost non-existent. Also, if a plane rises too high, oxygen becomes too sparse to fuel the engines.
And since a plane can suck in less and less air the higher it climbs, at some point it won’t have any more power to keep rising. Unfortunately, it can lead to a – shall we say – bad outcome. Actually, while flying at a lower altitude, airliners can also rely on the assistance of wind. But that high up, they would waste too much fuel to stay aloft.
On top of that, planes don’t fly too high because of the aircraft’s weight itself. The problem is that the more a machine weighs, the more difficult it is to bring it to a certain altitude. On the other hand, there was one aircraft that could fly way higher than usual commercial airliners. It was NASA’s Helios Prototype, an ultra-lightweight,
flying wing aircraft, and it reached the unprecedented height of 18 miles!Being able to get to this altitude, where the air is more than 100 times thinner thanat sea level – you can imagine how unusual this partially solar-powered machine was!Unfortunately, other than this aircraft, no other plane has ever risen this high abovethe ground yet.
Besides, Helios wasn’t a commercial aircraft with passengers on board. Anyway, all the reasons I’ve mentioned pretty much answer the second question that’s been bothering me, about whether airplanes could fly to space. Apparently, nowadays, it’s absolutely impossible. When an airplane is fast enough and has big wings that can support it in the air, the atmosphere does the rest of the work and holds it aloft.
As a result, the engines keep moving the plane forward, and the air flows under and overits wings. The clever design of the wings is of great use as well: when the air pushes them upward,it automatically counters the downward gravitational pull. But there’s no air in space; no atmosphere, no wind, and, therefore, no airplanes. Admittedly, there are such things as space planes.
These are vehicles that can fly like an airliner in the atmosphere of our planet and maneuver like a spaceship in the vacuum of space. This feat is possible because space planes are somewhere in the middle between space craft and aircraft. You remember the Space Shuttle? Yeah. So far, all the space planes have been rocket-powered, but when they landed, they had all the features of un powered gliders, or as the Astronauts used to say, it was like a “flying brick”.
By the way, do you think there will be commercial aircraft capable of flying to space any time soon? I hear Richard Branson is getting his vehicle ready. Write about your opinion in the comments below! But let’s return to our main topic – now it’s clear why commercial airliners avoid getting higher than their established cruising altitude.
But why don’t helicopters or small private jets fly at the height of 35,000 ft? Talking about choppers, they’re mostly used for flying short distances and usually don’t rise higher than 10,000 ft. They’re physically unable to get to the cruising altitude of large airplanes because,instead of using wings, they move by rotating blades.
Once the air becomes too thin, the rotors can’t support the helicopter in the air anymore. However, there are special turbine-engined choppers that can rise as high as 25,000 ft,but they’re unlikely to stay at this altitude for too long. As for small planes, most of them have an engine that resembles the one in your car.
As a result, it can handle only relatively short flights at a height of no more than 15,000 ft. On top of that, pilots who bring such planes to higher altitudes are at a greater risk of developing hypoxia – a condition where body tissues don’t receive enough oxygen. The problem of small planes is that they aren’t pressurized in the same way commercial aircraft are.
As a result, when a private jet climbs too high, the level of oxygen starts to fall fast, which can lead to rapid decompression. In any case, modern planes are worlds apart from the aircraft that flew half a century ago. Then, airline tickets cost five times more than they do nowadays, but the atmosphere inside a plane felt more like some exquisite dinner party.
And don’t forget large and comfortable armchairs where passengers could relax and talk to their fellow-travelers. These days, such luxury has been replaced with tiny seats, budget fares, and baggage fees. But one thing remains the same – and that’s how fast your plane flies. Interestingly, modern-day flights, in general, take longer because too many airplanes getin and out of airports, creating traffic jams.
As a result, you need more time to fly the same route than several decades ago. But what’s with the speed? The thing is that back in the ‘60s, planes were already flying at the most efficient speed for their engines. And since then, the plane engines haven’t changed that much. Today, most commercial airliners are powered by turbofan engines which work best at a speed of 400 to 600 miles per hour.
So, there’s no point in moving any faster than that because, in this case, planes would waste too much fuel and air travel wouldn’t be so cost-effective anymore. Surely, there are planes that fly way faster than the average commercial airliner. For example, military aircraft, with their turbojet engines, can reach breakneck speeds of more than 1,500 miles per hour.
But at the same time, while reaching such speeds, they spend astounding amounts of fuel. The Concorde plane could also accelerate to an incredible speed of 1,300 miles per hour while flying at its cruising altitude. At the same time, it used almost 47 lbs of fuel for every mile traveled, and accommodated only 100 passengers.
For comparison, the Boeing 787 Dream liner, with a cruising speed of 650 miles per hour,can transport 291 passengers and uses just 19 lbs of jet fuel per mile. No wonder the Concorde stopped operating in 2003 – this plane was amazing, but economically unprofitable. Ah, the ups and downs of air travel.