TechStuff Goes on Autopilot

That was actually a quote, Yes, he wasn't asking me that, And usually I do the first line of a novel. This time it was the first three sentences of a novel. But they were also short that I decided to string them together. You're crazy like that, you know, I'm crazy like a lot of things. So today we wanted to talk a little bit about, um, well, something that Chris and I do all the time, which is to go on autopilot like we do in this podcast. Oh yeah,

every darn week. Um No, we wanted to talk about the autopilot systems in airplanes because you know, you often hear that phrase about switching on autopilot, But what does that actually mean? What's it? What does that entail? How did we come up with this idea, you know, uh, because it kind of has this sort of almost magical air about it for anyone who is uninformed about the

way autopilot works. Right, Like, there's a big red button that says autopilot, you press it and pressed dough Everything's cool, you said air. Um, there's gonna be a lot of that. Let's get that out of the way right now. Yep, yep,

And uh, I'm a fan of Patrick smith On. Salani has a column called Ask the Pilot, because he's a pilot and people ask him questions about things like what happens at one of the engines falls off a jet and you know that kind of and he answer bad things, yes, but you know, not as bad as if all the engines from the jet. Right. No, but I'm thinking about it depends on if you are under the jet at the time. That's true. Um, but yeah, I mean. And and one of the things that he says a lot

of people, He's mentioned this several times. People seem to think that the pilot can get in the cockpit, close the door, push the red button, and the plane will fly itself to the next destination. And he gets out and thank you for flying with us, and it doesn't quite work. Then he collects the big fat check for all for pushing a button. Yeah, it doesn't really work that way, and you can do a lot, but it can't do that. It can it can even land a plane,

depending on the conditions and the systems aboard. But let's uh, let's let's take it back a step first. Let's talk about sort of the development of autopilot. So way back in nineteen o eight, there was a fellow by the name of Elmer Sperry, and he was developing something called a gyro compass, and it was it was using a gyrocompass and other sorts of gyroscopes that in combination could work with the systems on a on a plane to allow a automated steering. Essentially, what it did was it

just kept the steering steady. It's you know, it's kind of like, you know, this idea of just uh, you're honest, steady heading and it keeps you on that UM. And the first test flight of a a plane with um this sort of autopilot system was performed by Lawrence Burst Sperry, son of Elmer Sperry, which was again right around and it used four gyroscopes to help stabilize the plane. So the gyroscopes, depending on their attitude, and I don't mean

whether they were friendly or not. Forget you, you could fly that playing yourself. I mean their position relative to the rest of the environment would dictate how the system would work. And so that was that they developed the first true autopilot system, which was later used by a fellow named Wiley Post which is just a great name. Yeah, you know, he's an His name is one of those names that you hear every once in a while. Um. He was famous back in in in his time, which

was the earliest part of the twentieth century. Yeah, yeah, famous aviator and his name sort of just comes up every once in a while. Is him? I know that name? Why is he famous? Well? Is it turns out he uh, well, he flew across country. Yeah, and made headlines with that, certainly, and then he flew around the world. And the first time he flew around the world, he flew around the world with a navigator. Took a long time for him

to get all the way around the world. Um. And but the navigator was there too, not just navigate, but also make sure that that Wiley remained wildly and that he was alert and thank you, alert and capable of maneuvering the plane and not just you know, any time anyone has to do a monotonous task for a really long time, there's a danger that we will go on autopilot as and we'll stop paying attention and then disaster

can can strike. So he had a navigator. Well, then he decided that he wanted to try and do a solo flight around the world and this is three and so, uh, in order to do a solo flight and still be able to rest and you know, because these these flights were taking hours and hours and hours at a time just but you know, from one spot to the next before refueling and uh uh you know, it's it's a

long time to stay awake. So he would have had this, uh, this system developed by the Sperry's that would help keep the plane on course so that he could rest because otherwise, uh, he would probably have gone crazy. You go without sleep long enough and you start to go bunkers. So that was a very important development, and it's today autopilot is part of something a little more sophisticated. Back then, it

was it was a fairly simple system. But now it's part of the automatic flight control system, which in turn is one component of an airplane's avionics system. And before we go too far into this, I do want to say we have an article on how stuff Works dot com about how autopilot works, and it's an excellent article. I do recommend you go check that out if you want more information. We're going to give you the rundown on it, but it's it will help a lot if

you want to look further into it. There's a great article on our site is by William Harris as a matter of fact, who used to be one of my writers as well. So an avionics system in case you're wondering what that is, you know, we just mentioned that the the automatic flight control system is part of avion X. Avionics refers to electronic systems aboard a plane that are really designed to help control the plane and the key

elements of flight. And the other systems that are involved include things like navigation, collision avoidance, communication, UH and weather systems. So these are the very important systems that allow pilots to do their job, you know, and get as much information and have as much control over the aircraft as possible. And so yeah, they're really the original purpose of the autopilot was to help pilots be able to take little rest breaks, especially when doing something that's truly tedious, like

cruising at high altitude. When you're well, you're you're you've reached your your cruising altitude like thirty feet and that's it. You're you're stuck there for however long the flight is going to be before you have to start taking her down, and that can get you know, if you if you've got several flights today, that can get pretty tiresome. So the autopilot helps the the pilot kind of offload that so that the pilot is in the best shape to bring the plane in for landing or dealing with any

other unusual circumstances or even things like turbulence. Yeah. Yeah, if it's a smooth flight, it shouldn't be much trouble for the autopilot to keep the plane going where it's going. Um. And and it does that through a series of well course corrections. Really um. As it turns out, it's basically, uh, the idea behind the auto autopilot itself is pretty simple. Um, you have several control surfaces and we talked about this

in the past. You have control surfaces on the wings and on the vertical stabilizer uh known to those of us and the uh you just talking about planes sort of world that tail um and uh. You know you basically controls uh. It consents what's going on. It says, oh, well we're descending a little bit. We need to adjust the control surfaces to change the airflow and get the plane back up. You know these ten feet that we've dropped. UM. So it's at all it does is it's basically and

I'm grossly oversimplifying it, but um on purpose. So Yeah, basically, all it's doing is saying, oh, we need to we need to fix this, we need to adjust this and get it back to where we were. Um. And then it just makes these very subtle course corrections to get to keep the plane more or less where it is when the pilot hits the big red button. I don't even know if the big red button exists. It's slang

for what we're talking about. Right. So, so to get a little more in depth with this, uh, you you have a closed system, right, and that closed system includes sensors that are on these control surfaces as well. As other sensors that are part of the planes systems that provide information to a computer. Now, the computer takes this information compares it to whatever command the pilot has given. For example, the pilot might say I want to maintain

this altitude, this speed, and this course. And then what happens is the computer takes the information gathered by the sensors, compares it to the command given by the pilot, and then makes any adjustments necessary in order to maintain that

that command. Now that might mean uh, sending information to a a servo that will adjust one of those those control surfaces to make a bit of a change, either to turn the plane a little better, raise and go up in altitude or lower in altitude, whatever is necessary in order to maintain the command that was set by the pilot. So those those three basic control surfaces that Chris was alluding to include elevators, which that's on the tail of the plane, and that helps control the plane's pitch.

So if you imagine a plane that let's say that you're balancing a plane along its length, so it's you know, it can tilt forward or backward the pitches. That's what the pitch does. It allows the plane to either go up or down uh in uh angled in that way. Then you have the rudder, which controls the yaw that that's what twists the plane. And then you have the ailerons, which are on the rear edge of the wings. That's what roll is the plane to once that or the other.

All right, So those are your three basic control surfaces that can do these these changes to the plan's attitude in flight. And depending upon the autopilot system you have, you may be able to have one or two or all three of those under automatic control. So, and it's pretty easy to understand. A one access one access rather control system will control just one of those three surfaces, and it's usually the ailerons. If it's just gonna be one,

it's usually that. Two access controls usually controls the elevators and the ailerons, and then three excess controls controls all three. Clearly you wouldn't you don't have like a fourth one, poppa, and then hey, what's this, dude? Forget you rudder? You never get controlled. Uh, it's not the case. So the depending on that system, the autopilot is in charge of making sure that the any adjustments gets sent out to those different control surfaces to maintained the command that the

pilot has made. And the sensors include other things like gyroscopes which help determine the actual attitude of the plane, how it's you know, whether it's tilted in one side or the other, or the pitch is wrong. That's what the gyroscopes can help with. And then you have accelerators, so obviously determining what the speed is of the plane, whether it's undergoing any sort of acceleration or deceleration, altimeters which tell you how high up the plane is. That

seems relatively important. And then a compass which tells you which way you're facing. Also the more. But over the last several years, they the autopilot system has also depended upon GPS receivers, which can let the autopilot system know where the plane is geographically and thus make any sort of course corrections in order to even plot a course to a destination. So there's a little bit more that

can be offloaded onto a computer system. Now we're still not to the point where we're gonna have robot pilots. You know, these these autopilot systems are meant to help UM help pilots rest and and and plan for other parts of the flight. But they're not replacements. Yeah, so make sure if you're a pilot that you watch what you eat before you, uh, you know, take over the controls. Oh, yes, I had to Lasagna. This is Bob. I'm mixing those

up because it's airplane and airplane too. Okay, yeah, but yeah, you can you can tell um. You know from the very first uh when Wiley Post was using the the early Sperry system UM, which was based solely on on gyroscopes and compass readings, you know that that was a very simple version of what would later become these systems.

And now that we have all these different UM, different types of sensors and different types of input, the the autopilot system can be a lot more accurate than than those of the past UM and it has become a very very useful tool for an aircraft pilot to to rely on. Yeah. And also, uh, I should point out that these systems, with the servo mechanisms and everything that help control the surfaces, they are independent of the manual systems that are used by the pilot when the pilot

controls the plane. Whenever he or she is controlling the plane. UH. It's an independent series of of servos and every and other elements that keep these services moving. And the reason for that is because autopilot systems, like any other system, can fail, and UH, in the case of failure, you want to have the option for manual control so that the pilot can take over and everything will be fine.

And so in order to do that, you have to make sure there's some redundant systems there, because if it's a servo mechanism failure, which is frequently the case in an autopilot failure, then you want to make sure you still have a way of controlling that surface area or else you're really stuck. You've got some serious problems if if a system like that fails. Over Macho grande, I'll

never be over Mancho grande. UH the UH. And the other thing that's important to remember is that if an autopilot system is engaged, meaning that it's working, not that it has found the right person and they're going to build a family together, settle down and have a little being a little extra goofy this morning for reasons I can't understand, other than the fact that we were not able to come in our normal studio time because stuff to blow your mind was taking up the space in

front of us. So blame them anyway. Yes, when the autopilot system is is active, you want to be able to turn that off before you engage manual systems because otherwise, what's happening is you're fighting the autopilot because the changes you make, what's going to have is the sensors an autopilot system pick up the fact that you've changed the

or or that conditions have changed. So let's say that you're trying to bring the plane down to a different altitude and you start to do this and autopilot is already engaged the sensors and autopilots start to say, wait a minute, now, we're now we're going lower. And he told me, he told me at the beginning of this flight that we wanted to maintain thirty four thousand feet, So, gosh darn it, I'm gonna change the the altitude of this here plane. And so disengaging the autopilot is very

important before taking over manually. Now, I'm sure there are many systems out there that have sort of an automatic disengaging uh process, so that if a pilot were to take the controls, the autopilot would would turn off, so that you wouldn't have a pilot and autopilot fight over where a plane is going. But there have been in the past a few UM accidents and incidents that were UH linked in one way or another two autopilot failures. A lot of experts that I have looked at, UH

the writings rather not the actual experts. I mean I look at them too, but they get a little self conscious after a while. But according to their research, it seems to me like autopilot failure is not generally a cause for for accidents. It tends to be something else that's happened. There have been a few cases where autopilot was disengaged and then perhaps turned back on again at a time when a plane was experiencing trouble, and that

didn't help matters. But it doesn't look like autopilot failures often result in catastrophe, mainly because we have these well trained pilots that are in the cockpits that can take over when that happens. That's true, UM and UH, I think it's time to bring up some negative feedback, the negative feedback loop. Yeah, now, a feedback loop is basically a and and this doesn't necessarily have to be a an electronic thing. I was reading an article and wired

about this. If you've ever seen those, um uh, those speed indicator things on the side of the road that say, hey, you know speed limits thirty five, you're doing forty two, pal slow it down and it flashes at you. UM, that's creating a feedback loop. They used that example specifically, so basically, UM, that article was talking about how they're actually fairly effective um at getting people to slow down

because they're providing you feedback on what you're doing. And uh, that sort of creates this sense of, well, I should probably behave myself and stay close to the speed limit in this area, UM, I don't want to get pulled over, or or some people are thinking I don't want to get caught and other people are thinking I am going too fast for this neighborhood. Exactly. I think I think most of the the people I encounter are of the first part where they look around, like, I don't see any cups.

Just screwed up the levels there too, I'm sure probably, um, but but in this case, uh, the autopilot system uses a negative feedback loop. Um. So let's say you're flying at thirty four thousand feet okay, and uh, you know, I would imagine when I used ten feet before that was a I'm thinking that's probably a fairly subtle change

for a plane in flight. So let's say it goes down ten feet, um, maybe as a result of a little turbulence or something, and uh, it sets off a you know, a signal in the processors because the sensors have detected that there is something. So that's negative feedback, and it says, oh it's something's changed. It's not supposed to be this way, fix it. And so it's just constantly going through this loop, is it okay? Yes, all right, never mind, yes, never mind, it's okay, we're tilting, all right,

fix that? Yes, yeah, it's Um. If you want to know another negative feedback loop mechanism that you're probably pretty familiar, whether we did an entire episode about it, the thermostat. I because let's say you set your thermostat for we'll say seventy degrees, because I like it right around there in my house. Um so seventy degrees. So when the temperatures at seventy everything is copathetic. Nothing gets turned on as soon as it starts hitting seventy one. Then you

have the system click into place the air conditioning. The air conditioning system itself starts to starts to fire up, which ironically makes it cooler and uh then starts blowing cool air through the through the house. And once the air has become cool enough around the thermostat and the internal thermometer detects it, then it switches back off again. And that's a negative feedback loop system. I'm just glad you've upgraded from that swamp cooler. I'm just glad I

upgraded from opening up all the windows and shouting at people. Yeah, are happy with that. They are, uh yeah, yelled get off my lawn. But I live in an apartment, so it's awkward. M Um yeah now uh yeah, now sorry I just said yeah now twice three times. Then okay. So, negative feedback loops use a receptor, a control center, and an effector. Basically, the receptor is what's figuring out what's

going on. It sends information to the control center. Um, and then the affect or is the thing that makes the change. So yeah, and the system in system of the autopilot, we're talking about the sensors are the receptor.

There are many different kinds in this case. Yes, the control the control center is the computer that takes in all this information, and the effector are the servo mechanisms that the computer sends commands to that then make adjustments to those control surfaces so that the plane does whatever it was the pilot wanted to do. And these systems are incredibly sophisticated now to the point where, like I mentioned before, they can actually land a plane and sometimes

are used to land a plane. Not not generally speaking. Most of the time it's a human pilot that's landing a plane. But in cases where visibility is really limited, Uh, there are times where they they will they will incorporate an autopilot system in order to bring the plane in and land it when there's a fear that maybe human failure could play a role in a safe landing. So it's not common, but it can happen. Yeah, they prefer not to do that. Um, it's usually better to that.

That's not a time when you want, uh the system to fail. It's it's usually a pretty a pretty dramatic turn of events for that to happen because normally pilots don't bring planes into UH to UH to an airport where there's already that kind of limited visibility. If there, if they can help it, they'll usually divert to another really air traffic control will tell them to divert, divert to another airport UH that they can get to safely, rather than go into an airport where there's going to

be conditions that will severely limit visibility. Now that's not always possible. I mean in commercial flights that tends to happen quite a bit, because you know the past, your safety is so important, But with something like a military flight, it may not be a possibility. So um, different cases, depending on the whole scenario there. But it is possible and it has happened now. UM, I don't know. Did you want to talk about other types of autopilot at all?

What you mean like cruise control? Well, I was talking specifically about cars because that's been that's been coming up a lot lately. Things I've been talking about how UH in three years cars will be driving themselves. Well, they're already doing that. If you work for Google, Yes, they're also rear ending people. Um, people are backing up into them, you know it. They feel like there's no one in that car. Reverse boom, Google owes me money. That's all allegedly. Yeah,

I got I used the word allegedly. It's all right, that's the way that works. Send hate mail too. Um. Actually, uh, well, of course Google is testing systems like that. Um, but you know that it is a little more difficult in some ways for a car, because for a plane, you know it's going that way and there's probably nothing in front of it directly. Um. Generally speaking, air traffic is

less severe, less around than ground traffic. Yeah. I mean once you get toward an airport, then yes, air traffic starts to pick up, but by then usually pilots have disengaged the autopilot system anyway. But with roads, you have things like, um, weather conditions trick into account, slippery roads, you've got twists and turns, You've got squirrels. Construction, Um, don't have a whole lot of construction at th feet. People who are not paying attention while they're driving in

front of you. People who are applying makeup shaving so um shaving while applying makeup all reading Yeah so um yeah, they're they're working on systems to do similar kinds of things with cars, but it's a much more challenging or at least I think so much more challenging proposition to put that kind of a system in a car, because there's so many more factors that uh an autopilot would have to take into account. Of course, now they are it's pretty common to find at least the higher end

models with sensors that will help you park. Um, they have, you know, those auto parking cars, the whole collision detection stuff so that it can tell when it's close to another object and thus uh adjust the control so that you avoid colliding with it, which use uh you know, some radar and cameras, infrared systems, um, you know these things.

Lane changing. I like that system to where um, you know, it's able to detect where the lanes are and kind of keep you in place, make sure that you know you're not gonna smash into someone who's in your blind spot, yes, which is very important, especially if there are a lot of bicyclists around. There's you know, there's these systems are are emerging for the for cars because the vehicle's brilliant airplane is one too, but there are emerging. It's kind

of an emerging technology for cars. And one thing that will really help this technology propagate is when we actually see it and lots and lots and lots of different cars, because then you can have a system where the cars are just one element within the system. Now, see in the plane, we're talking about a closed system that's all contained within the plane itself. With something like cars and traffic, you're talking about a system that could, in theory, be

a meta system, a system of systems. Each car would have its own system, including things like sensors for collision detection and lane detection, all that sort of stuff, as well as GPS receivers so that the car knows where it is and is navigating to the appropriate destination UH and maybe even things like other kinds of radio receivers so that the STEM has information about traffic reports and construction delays and things like that so it can reroute

around those. But then you have a system of systems where you could have an entire UH infrastructure that can detect where these cars are based upon their own electronic signatures. If you've built in stuff that's directly in the roads or part of the whole infrastructure UH. And then the system of systems could help maintain a good fluid traffic by helping these these individual cars route to the appropriate

destination in the most efficient way possible. So then the closed system it doesn't isn't truly closed because it becomes part of a larger system. Uh, that's pretty I mean, it's incredibly complex, and we're not there yet, not by a long shot, because we would we would need not just lots and lots and lots of cars that have these these sensors and these mechanisms incorporate into the design of the car itself. We would have to go and build out the infrastructure in the cities, which is an

entirely different prospect. I mean that's that might be slightly expensive, and it might take more than a decade to complete. I mean, based upon how long certain streets in Atlanta have had metal plates on top of potholes, I'm gonna guess that incorporating such a sophisticated system that would need to be really pervasive throughout the entire infrastructure would probably take about two thousand years. Well, it would take um you know, depending on the size of the area covered.

Like a municipality could probably do it. A lot more quickly than a nation covering all of its uh you know, major highways and um and then you start talking about surface streets and back roads and things like that, it could take a very very long time. Plus there will be people who are loath to give up their older

cars that don't have these systems. You know, even even if there's a new system that has manual versus automatic, I think there are a lot of people who would be um who would have reservations about switching to an automated driver system. Either they would feel powerless in that situation, or they just they just genuinely enjoy driving. Because I've heard there are such people. There are such people that I don't understand them. They come from a different planet

than I do. But you don't, I don't. I don't judge. You know, they can be crazy. I don't. That's fine. I know lots of crazy people. I work with. Most of them, or most of people I work with, are crazy. They weren't that way when I started. I don't know what happened. Yeah, anyway, So yeah, these autopilot systems are finding their ways into other different vehicles, so cars, boats as well, and other sorts of vehicles, and I expect

that will continue to see that. I mean this whole idea of an automated system that helps you get to where you're going. Uh, it's just another example of us trying to create technologies that make our lives easier, more convenient and uh and uh paving the way for our robot overlords to easily conquer us when they choose to rise up against us. Awesome, as in the documentary Terminator. Alright, then, excellent.

I'm glad that we covered this topic. And now I'm going to go and turn my house into a luddite luxury home. So lots of lots of this unfinished wood. Really, that's what I'm looking at, guys, isn't it good? So you, guys, if you have any suggestions for future topics, whether it's a reference to a Beatles song or possibly something not connected at all with technology, because we've had a few of those and sometimes we consider them just for funzies,

let us know. Send us a message via email address this tech stuff at Discovery dot com, or let us know on Facebook or Twitter. Are handled, there is tech stuff. H. S. W and Chris and I will talk to you again really soon for more on this and thousands of other topics, visit how stuff Works dot com. Brought to you by the reinvented two thousand twelve camera. It's ready, are you