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The Miracle of Air Travel

   

Airplanes and flying almost never make the news unless there’s a crash. So join me, if you will, on an appreciation tour of the magnificent machine that is the modern air travel system.

Growing up with a father and other family members in the Air Force, I’ve been around planes all my life, and I’ve always had a particular fascination with them. I’ve been a faithful devotee of Microsoft’s Flight Simulator series since 4.0, over 25 years ago. There was even the time I got to fly with my father’s friend in a Cessna, and he let me take the controls to land it. (Don’t tell the FAA about that one!) I love airplanes in all their history and variety–gliders, biplanes, turboprops, jets. I realize that most people don’t have that kind of romance about them, and that’s fair enough. For most of us, they’re a convenient way to travel long distances, although it’s fair to say they aren’t always comfortable or inexpensive.

Still, it’s worthwhile to take some time to examine what all it takes for this system to work, and why it works as well as it does. For starters, it’s obviously much more than just airplanes themselves. You have airports, aeronautical maps (physical or digital), air traffic controllers, baggage handlers, flight attendants, flight crew, service desk staff, custodial staff, and on and on. It would take too long to describe every job in our air travel system–the point is that there are dozens, and each is crucial to the functioning of the overall system.

Put aside, for the moment, the process of designing, testing, and building aircraft–an industry which employs hundreds of thousands of people. Without them, we wouldn’t have anything to fly in at all. They are absolutely essential. But focusing on the actual process of air travel, consider everything that must happen for you to find a flight, book it, check in at the airport, check your bags, board the plane, have it take off, travel, land safely, deliver you to your gate, disembark you from it, and get your bags back to you.

Computer systems manage the ticking and reservation process, of course. Flight ticketing is something of an arcane science in and of itself–the way prices vary is not obvious, and is governed by bizarre industry and airline rules. Finding the best price is confusing but at least you can book a ticket and be reasonably sure you will get to your destination. The airlines have to manage the seating on each flight, too. It’s true that airlines routinely oversell their available seats, but it very rarely results in anyone being involuntarily bumped from a flight–the Federal Aviation Administration estimates only 1 in 10,000 passengers are so denied a seat. That’s 0.01%. It’s pretty safe to assume, then, that you’ll at least be able to check in and board your plane. Your checked bags–if you have any–will be weighed, tagged, and delivered to baggage handling staff who will make sure it gets into the cargo hold of your plane. If you’ve ever wondered why the weight limits for checked bags exist, it’s simple: planes are very sensitive to weight. Too heavy, and they can’t take off.

It’s easy not to notice when your plane arrives at the gate on-time and ready to go. It’s what we expect, isn’t it? When a plane is late, though, it can be frustrating and even very stressful, especially if you need to be at your destination at a specific time, such as to make a connecting flight. But a lot of the time, the reason planes are late has to do with safety. Planes can be delayed because of mechanical problems that need time to fix, or due to airport congestion that doesn’t allow planes to move through the airport and its airspace quickly. The next time your plane is late picking you up, just remember: it was probably delayed in the name of safety, and taking a few minutes or hours of your life is better than being dead.

That brings us to what happens once you’re on the plane and it’s ready to go. It may have been fueled up for the trip, de-iced if it’s cold and wet or snowy. Before the pilots can pull the plane away from the gate, they must begin a series of checklists to ensure that the overall safety of the plane and its passengers is in order. In the past, these checklists were in binders or on little cards, and pilots had to follow them step-by-step. Increased workloads, distractions, and poorly-organized checklists led to plane crashes. There were times when pilots missed key steps, such as extending the slats and flaps on the plane’s wings, without which a jumbo jet can’t even take off. These days, commercial jets have electronic checklists which simply won’t let pilots proceed unless they have completed all the necessary steps, and since they are wired into the plane’s hardware, they know for certain whether each step has been done.

Once a plane is ready to leave the departure gate, the complex dance of air traffic control begins. Planes must be directed, both by staff on the tarmac and ground control staff in control towers, to appropriate taxiways and their actual takeoff runway. This may sound like a simple process, but airports are busy places. There can be dozens upon dozens of planes moving about an airport at any given time. There are always planes arriving, planes taking off. A new plane could be touching down or another taking off more than once a minute, and this is on top of whatever planes are already on the ground, trying to get somewhere. It takes intense, careful management to keep planes from running into each other on the ground. Apart from staff who pay close attention, the best technological tools we have are advanced ground radar systems and intelligent runway lighting. The former helps ground controllers know exactly where planes are (and which planes they are) at all times, and the latter warn planes when particular runways and taxiways are occupied. Both help to avoid collisions. To put it bluntly: you never want to two planes on the same runway at the same time. The deadliest plane accident in history–the Tenerife disaster–occurred due to poor ground control that put two planes on the same runway simultaneously.

Fortunately, technological advances and better practices among staff have dramatically reduced so-called “runway incursions.” Your plane, thanks to thorough, meticulously documented maintenance, is also very likely to complete takeoff without incident. Once you’re in the air, it’s time to sit back, relax, and wait to touch down. But for air traffic controllers and the flight crew, work is only just beginning.

Those planes constantly departing from and arriving at the airport don’t come out of nowhere. Air traffic controllers must manage communications between many planes at once, safely guiding them into and out of the airport and being mindful that none of them hit each other either in the air or on the ground. Like other aviation-related systems, air traffic control has also benefited immensely from technological advances. ATCs used to push around physical strips of paper called flight progress strips to denote what planes they’re responsible for directing, and what their current status is. Even when done on paper, it’s a remarkably effective system. Transfer of control from one person to another was denoted by physically handing off the strip, which contained all the instructions and other relevant information the new controller would need. Air traffic control, however, is becoming ever more automated, and efforts are currently underway to remove the possibility of human error from the ATC role as much as possible. A long-term initiative called NextGen is key to this, as it ties control systems on the ground to systems installed on each plane, allowing aircraft computers to see things exactly the way the airport does. Each plane will know exactly where all other planes in the area are, and thanks to automated flight computers, midair collisions can easily be avoided. It shouldn’t be necessary for humans to micromanage air traffic to such an extent when each plane can act as an autonomous, fully aware node in a sky-to-ground network.

It’s also true that most planes available today have the ability to fly largely unaided, but this is often exaggerated to an absurd degree. What has changed is the extent to which pilots must manually control the various aspects of flight: throttle, trim, pitch, and so forth. Once a plane has taken off and reached cruising altitude, it can automatically fly to preprogrammed waypoints, requiring pilot intervention only if something goes wrong or the plane encounters bad weather. Even when pilots do take the controls, they are almost entirely electronic now. Today’s state-of-the-art commercial jets are programmed against pilots doing things like putting their planes into dives or rolling them too hard in one direction or the other. These can be overridden in some circumstances, but under normal operation, there’s no need to do them–so the computer doesn’t allow it.

Planes can also land themselves automatically, but in practice this is rarely done. Landings remain human-controlled largely because setting up an “autolanding” takes a significant amount of preparation work, so much so that it’s usually better for the pilot to simply do it directly. That said, in poor visibility conditions, automated landings are extremely effective–a plane’s sensors can see much better in the fog than any human, after all!

Weaving through all of this (and as yet unmentioned) is the security apparatus, which is growing and becoming more technologically advanced all the time. I am personally not a fan of how the Transportation Safety Administration works at a frontline level, but I do have some appreciation for the ways in which myriad security measures function to manage baggage, cargo, and passengers. I am not convinced they offer any improved safety by their presence, but to integrate so many complex security measures into an already-complicated air travel system without massively disrupting its operations is some kind of achievement.

At this point, we’ve had about a hundred years of commercial air travel, and we’ve learned a lot. We may not give much thought to what an incredible marvel modern air transportation really is. It’s easy to take for granted. But it is a constantly-evolving system, almost like an organism made up of countless people, machines, and data and items flowing between them. Flying is safer today than it ever has been, thanks to advances in computer technology, sensing equipment, and personnel management. Not all problems are solved–there are always new challenges to address–but the fact of the matter is that we have the capability to travel from one major city to almost any other major city on Earth in less than a day, and we do so with a level of safety unmatched by any other mode of travel. Nothing even comes close. Even when planes crash, those events are profound learning experiences that help make all future flights safer.

In the near future, civilian aviation systems will no doubt have to adapt to more changing conditions. Demographic shifts, climate change, and an unavoidable migration from fossil fuels will necessitate perhaps radical alterations in how and where we fly. But our flight systems are also resilient and dynamic. I look forward to seeing what air travel is like in the coming decades.

And I’m sure my plane will still be delayed once in a while.

Photo by oliver.holzbauer