What is an "Auto-Pilot?"

Just about every time there is some media coverage about an aircraft, it's usually an accident of some kind. And, in that coverage there is usually the mention of an aircraft's "auto-pilot." I seriously doubt the general public has an understanding of what an auto-pilot is and what it does and doesn't do. Most people think it's an "ON" button that takes over and the pilots are no longer needed.

First, not all aircraft have an auto-pilot. For the most part, any aircraft you fly on as an airline passenger these days, has an auto-pilot(AP). This is not always the case, however, and I'll talk about that a bit later.

The basic reason for an AP: to ease crew workload. Patrick Smith stated in one of his articles, that when you look at any modern flightdeck, there is no "land at nearest airport" button. However, in the eyes of some completely ignorant douchefaces, the AP has made pilots obsolete, and to be an airline pilot is to be paid lots of money for a job that is all automated anyways. Yes, in the same way that Microsoft Windows has removed the need for any career IT personnel.

So, let us get into some facts. There are two basic types of AP, 2 axis and 3 axis. Most of the regional jets have a 2-axis AP. Without getting too technical, it will hold the wings level and even follow some type of lateral course, and hold a set altitude. Nicer, larger planes will have 3-axis APs, which are coupled with auto-throttles and will also follow a vertical track through the air as well. (called VNAV)

When then the AP is on, the pilot is not just sitting back drinking coffee doing nothing. In many cases, the pilot is still very much flying the aircraft. They are doing so through the AP itself by pushing buttons and turning knobs, rather than making control inputs on the yoke directly. In this case, the pilot is not at all being "replaced" by the computer. The computer is merely an extension of the pilot's hands.

When you are just cruising along at high altitude, its very nice to have a computer to hold the wings level and hold altitude. Ever feel really really tired when driving, and when you have your buddy switch with you and start driving, you are all of a sudden awake? That's the workload difference between just watching over things, and actually be constantly analyzing the motion and position of the car, and putting in all the steering and accelerator pedal inputs.

I have flown routes into places like Atlanta, Chicago, and New York, which are some of the busiest airports in the nation. Workload can be very high in these environments. Especially when bad weather is further complicating things. Having an AP to help you out here can be very advantageous as well, since you're attention will be divided among more than a few areas.

The other side of the coin here is that the FAA seems to be pressing the issue that flight crews operate with the AP on damn nearly ALL THE TIME. They want the AP on shortly after take off, and they don't want it off until a few hundred feet from touchdown. For several reasons, this is a bad idea in terms of a mandate. The AP does lower workload in most scenarios. However, not all scenarios are made easier by AP usage. Visual approaches are a great first example.

During a visual approach, a pilot will be simultaneously slowing the aircraft, banking the aircraft, and pitching the nose over. This is easily done all together when hand flying the aircraft. To do this with the AP, you will be doing three different things, having to use multiple sets of knobs and buttons. You might be selecting a heading mode, then turning a heading knob, then selecting a vertical mode, and setting it with a knob, and then you might be pulling the power back as well, to control your airspeed, or selecting a speed with a knob for a 3-axis AP. Oh, and you then might be arming and tuning and approach mode to back up the visual approach. And in doing so, you're spending a lot of time looking inside when you are in a congested terminal area. Does that sound like a lot of work? You would be correct! It is.

To explain this in a different way, think about driving your car with an AP. Think about driving down a highway, unable to just seamlessly change your speed with the accelerator pedal, and smoothly point the front of the car where you want to go with the steering wheel. Instead you have a button to select if you want your car to maintain a certain speed, or if you want to set up a constant acceleration or deceleration. Then, you have a knob that you can set it with, say, "60MPH." Then, to steer, you have to select the correct mode on your control panel, to change the direction of the car, and then a knob to actually tune in what direction you want.

Lets also consider arming a NAV mode like having your car AP follow a GPS course that you program in. Sounds great. However, there are still things like stop signs, speed limits, and traffic lights to content with, not to mention other traffic! The GPS unit doesn't know about these things. So, just telling your car to go to the shops, and sitting back with your coffee, is asking for some trouble. You need to be aware of everything that is still happening around you. Not to mention, it takes you, the driver, the understanding and knowledge to program the GPS with the correct routing in the first place!

Here's another reason its bad that the FAA wants the AP engaged at all times. In airline flying, there is something called, "a deferral." This happens quite a lot, actually. Way more often than you would ever think. Why is this? Well, honestly, its based on money. There is a large amount of items and systems on an aircraft that have been deemed not 100% necessary. The FAA allows the company to still operate this aircraft, carrying paying passengers, with these systems inoperative. Some of these deferrals have certain procedures for the company and crew to follow when operating the aircraft with these systems being broken, others restrict the aircraft to daytime operations only, etc, etc. It really varies based on what system or systems are inoperative, as you would expect.

Now, there is a scenario called an "RA." This stands for resolution advisory, and basically, this is when two aircraft are on a collision or near-collision course. The aircraft themselves have proximity monitoring systems which will detect this, regardless what the weather and viability is. The FAA mandates that the AP be disconnected, and the evasive maneuver be hand flown. Why? Because the auto pilot will not react in time. Well, it is perfectly legal for an aircraft to be dispatched for a flight with a full load of paying passengers, into crap weather, with the auto pilot deferred. Now, if all pilots are following the FAA's recommendation to only fly with the AP on, we might not quite be as good at handflying as we should be. After all, we are "pilots," right?

Of course, none of this is even touching on just how often a pilot has to override the automation in an aircraft because its doing something unexpected. It could be for a million different reasons why the aircraft doesn't do what it should do, but regardless of the reason, the pilot needs to be vigilant of the plane at all times and not let the airplane do anything unexpected. I have seen aircraft automation do weird things countless times. Sometimes, its because I set something up wrong. (computers are famous for the whole "garbage in, garbage out.") Other times, its a error or failure in the AP itself. Other times, something totally weird happens. No idea why, but the plane just does something totally strange and unexpected. Just like Microsoft Windows does things, usually on a daily basis, that you don't expect.

Either way you slice it, the number of times that I had to "take back" the plane from the AP, and put it back on track, is nearly countless. For someone to make the argument that aircraft accidents are caused by pilot error, and taking the pilot out of the plane will drastically improve air safety, is to reveal their true ignorance and completely ignore the actual underlying causes of these accidents. Don't forget, if the AP does something unexpected and turns the aircraft into a mountain, it's still put down to pilot error, since the pilots (yes, plural!) didn't catch the error and do something about it.

An AP is really just another tool for pilots to use. When used properly, just like electronic engine controls, weather radar, etc, it will help pilots manage tasks and contribute to a safer operation. People who really think an AP removes the need for a human pilot, truly have no idea what they are talking about and are just making noise trying to get attention. Do you think the plane full of survivors on Sully's Airbus that landed in the Hudson would rather be on a plane that was flown solely by a computer? How about Al Haynes' DC-10 that crashed in Sioux City?

Above image from toonpool.com