An integral part of everyday commercial flying, autopilot (AP) has become a household name in the industry. Unlike the days of past, modern pilots spend most of their time on autopilot. But while it may seem like all we do is press one button and sit back, there is actually a lot more depth to it’s use than might be visible at surface level. In this blog, we will explore what autopilot is, how we use it, why it matters, and the future of AP.
Autopilot is still work, just not the same kind
I remember one particular story as a young trainee. We had some family friends over for a barbecue on a fine summer evening. Towards the end of the sunset, the elders started chatting and questioning my dad about my aviation career, which was to begin in a month or so. During that chat, they inquired a lot about why exactly I even chose to be a pilot. But at some point, that conversation took a turn and they started throwing some of their own beliefs in, discounting what pilots do; that all they do is hit the autopilot button and just sit back. While I didn’t believe them for a second, it was only until I flew commercially that I recognized just how much work flying autopilot is.
On most commercial flights, shortly after takeoff pilots will engage the autopilot with the press of a button. This allows the computers onboard the plane to fly the physical aircraft via the use of the Flight Director. The Flight Director (FD) is a set of bars on our instrument panel that are programmed by the pilots. In manual flight, we manipulate the physical controls to hold an artificial airplane symbol inside the flight director. In autopilot use, the artificial plane is held inside the flight director by the computers. Guiding this FD is a plethora of information, divided into pitch (up/down), roll (left/right), and yaw. All of this information is fed into the autopilot in real time, meaning pilots command the change and the autopilot executes it. So, even though we are not physically holding the controls to fly the plane, we are still inputting every command. As long as either the pilot or the autopilot matches up the artificial plane with the FD, the actual aircraft is flying the intended path in space. Understanding what input we must give the computer, against what result we are expecting, and monitoring said results against known limitations is the work of pilots on autopilot. So as you can see, autopilot is still work, just not the same kind.
Diving Deeper
As I mentioned earlier, the autopilot itself can be programmed in three distinct, basic categories. To avoid over complicating with the finer details, I’ll just cover the big picture.
Firstly, you have vertical movement (up/down). These are inputs, that allow the aircraft to achieve movement in the vertical axis. For example, vertical speed (VS) is to change the rate at which the aircraft gains or loses altitude. Sometimes if we have to steepen a climb, we may choose to set a higher vertical speed (calculated as feet per minute or fpm). As a passenger in the climb, you might look outside and notice or feel as if the plane is pointed further up in the sky. This is because the pilots changed the VS let’s say from +500 to +1500 (the “+” denoting the aircraft gains altitude, “-“ denoting the opposite), causing the autopilot to make the appropriate change in the most comfortable and accurate manner. Other types of vertical inputs include Pitch, IAS, etc.
Secondly, there is lateral movement (left/right). These are inputs that allow the
autopilot to change aircraft orientation on the lateral axis. For example, as you sip on and enjoy your refreshments you might feel the airplane changing direction. One mode that can cause this is the heading (HDG) mode. In HDG mode, ATC might request we change our heading from 180 (pointed south) to 270 (pointed west). When we input this change, the aircraft will calculate how much roll is required to achieve a comfortable, yet proficient right turn. First the FD will move to show where the plane must go to make the required change, and shortly behind the artificial plane will follow. In seconds, they will sit "on top of each other", denoting that the change has been made. All of this occurs at the highest degree of accuracy and passenger comfort. As a passenger looking outside, you might notice this as the right wing pointed towards the earth, and on the opposite window the left wing pointed to the sky.
Worth saying a few words on is the nav mode. During the pre-flight stage (when passengers are sitting at the gate), the pilots are inputting GPS waypoints to the destination. This can range from ten to over a hundred, depending on length and route complexity. At most operators, these waypoints can be automatically programmed with stored routes; pressing a few buttons programs all waypoints instead of manually typing each one out. Once these points are inputted into what we call the Flight Management System, ATC will, in flight, clear us on route. This means we swap the lateral mode from heading to nav, which tells the computer to now follow the pre-programmed points. If the next waypoint denotes a turn, the aircraft will automatically turn itself to the next waypoint, without any input from the pilot. This is the principle difference between heading and nav mode; pilots must set each new heading before the autopilot will execute, nav mode just follows whatever was programmed into the computer.
Benefits of Autopilot
Since it’s inception, autopilot has completely changed the way we fly. For one thing, it allows us to fly much further than we ever dreamt possible. For another, it takes the physical task of flying, away from the pilots and offloads it onto the computer. This gives us more mental capacity to handle other parts of flying, such as programming the computers, checking weather, troubleshooting issues as they rise, or simply taking a brief moment to enjoy the view. Imagine just how much further driving could take you if you weren’t fatigued by having to hold the steering wheel and manually make gas/brake changes the whole time. Thirdly, autopilot has drastically increased the safety factor of aviation. With autopilot we are able to fly into weather that is more adverse, commit to approaches when we can’t even see the runway, and manage onboard emergencies to a high degree of effectiveness. So as you can see, autopilot has played an integral role in making aviation the safest mode of transportation.
The Future for Pilots & Aircrew
You might be asking yourself, do we even need pilots? I mean, the autopilot can fly in every axis imaginable. It can do it faster, more accurately, and safer than a human could. So what is the point of having pilots? Well, answering that question comes down to both objective truth and subjective beliefs. Objectively, we still need pilots to intervene the autopilot should it make errors. Although quite rare it does happen. In addition, pilots are there to manage the system from start to finish. Remember my earlier point about heading vs nav? Well, the autopilot will only do what the pilots program it to do. You will always need someone to actually input the command. Plus, there are still scenarios where critical human thinking can help save lives. Remember the Sully incident, in which a dual engine failure caused by multiple bird strikes caused the jet to land on the Hudson? Research and background on the pilot shows us that he was perhaps the best person for that fateful day. That’s because in his past he had been a proficient glider pilot, and had experienced similar situations during his time in the military. Ultimately it was his sheer experience and critical thinking that came up with such a novel solution, not automation. Prior to that day, no pilot had ever experienced or trained for a dual engine failure shortly after takeoff at low speed and low altitude.
Subjectively speaking, I personally don’t think we are quite ready to board an aircraft with an empty front end. The truth is that people love pilots and aircrew. Despite the terrible situation at airports right now, being a pilot is every kid’s dream. When aircrew are seen walking around at terminals, it provides a sense of pride. Seeing pilots as you take a quick peek at the cockpit is a form of reassurance, that after all is said and done there are humans in there with friends and family just like the passengers. The comforting voice of the captain over the radio provides confidence that when a situation goes “south,” we will be in the safest of hands; the same way the calm demeanor of a doctor provides comfort before a risky surgery. Had none of that been there, I am not sure people would even WANT to fly.
On the topic of artificial intelligence, autopilot, etc I believe there is still a long way to go before these automated systems will be certified for use without pilots. Just look at how long it has taken regulations to certify automated technology for cars. The best of driving technology can barely differentiate road signs and pedestrians. By that regard, the complexity of flight and the tight safety standards mean that pilots will still be around for a long, long time. Plus the question of critical thinking still remains. So until that day, make sure to ask to see the cockpit. Ask to sit in the seats and look at all the buttons. Ask the pilots about the autopilot, perhaps share a few thoughts or questions of your own. At the end of it all, sit back and relax knowing that someone just like yourself, assisted by their not-so-human pilot, is going to take you flying in a metal can hurling at hundreds of miles per hour. Just a century ago, it was only a dream.
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