Proper navigation is the key to a successful flight.

Lots of travelers wonder how pilots navigate on the ground, as well as in the air. Next time you’re taxiing around an airport, try to notice the different types of markings. There are lights, signs and painted symbols, letters and numbers right on the paved surfaces.

It would take several pages to even attempt to explain it all, but here are a couple for you: When you see a black sign with a yellow letter on it, you’re on the taxiway designated with that letter. However, if you see a yellow sign with a black letter on it, that sign will usually have an arrow pointing toward a specific taxiway.

And how do we know how the taxiways are designated? We carry information for hundreds of airports around the world, and each airport has an airport diagram that pilots can read like a street map. The diagram is usually sufficient, but if we need assistance while taxiing, we can also simply ask the ground controller for help. (Being a woman certainly helps, as I have no problem asking for directions when I need them!)

Wingtip clearance is sometimes marginal while taxiing, especially when two jumbos are passing each other, but we’ll have clearance if both jets adhere strictly to the taxiway centerline. There is also a little-known tool we pilots use called “cockpit geometry.” We can’t actually see our wingtips in many planes, but we can tell whether our wingtips will clear a certain path by using other specific reference points on the plane.

Regarding airborne navigation, these days we program our entire course before we ever leave the gate. Some routes are even loaded for us automatically, especially if we’re headed overseas. This minimizes the chance that a pilot will load an incorrect coordinate. Whether a route is loaded manually or automatically, the pilots always cross-check the route against the actual clearance received by air traffic control. Routes can easily be changed once loaded, and we have minor changes—and sometimes not-so-minor changes—on virtually every flight.

Many passengers also wonder how often we use autopilot, and when a pilot would choose to hand-fly. The autopilot may be used on every single phase of flight but one, and that’s the actual takeoff. Although we can use auto-throttles on takeoff, pilots still have to steer the airplane down the runway and rotate the plane (pull back slightly on the yoke or stick) manually to become airborne.

Generally, most pilots prefer to hand-fly the first part of the flight. Some pilots will put the autopilot on for the first time at a few thousand feet, some a little higher up, and some like to fly the plane all the way up to cruise altitude. Why? Because flying the plane is more fun than watching the autopilot fly the plane. Once we’re at cruise altitude, though, I don’t know of any pilots who prefer to maintain a constant altitude and course, and the autopilot invariably comes on then if it wasn’t on already.

On descent, some pilots prefer to hand-fly, while others prefer autoflight. Most pilots want to hand-fly their approaches, but for practice or if visibility is really low, we’ll sometimes fly an autoland approach and the airplane will land itself. In order for this to happen, the plane, the pilot and the airport all have to be certified. The pilot still extends the flaps and gear and controls the speed while the autopilot flies the airplane. Pilots must demonstrate during annual checkrides their proficiency in programming autolands, which must be used with very low visibility.

With all the sophisticated navigation equipment we now have, how can a pilot land at the wrong airport? (It does happen, although rarely.) It goes without saying that it should never happen, but pilots are human, and if they rely entirely on visual references, it’s not that difficult to mistake one airport for another. At the carriers I’ve flown for, it’s absolutely mandatory to back up everything electronically that we can see visually. If this isn’t done faithfully, landing at the wrong airport is possible—and that pilot may soon be out of a job.

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captain meryl getline(www.fromthecockpit.com) is a B777 pilot for a major U.S. airline and flies both internationally and domestically. She also writes a weekly travel column for www.usatoday.com (“Ask The Captain”) and is the author of The World at My Feet. Email Captain Meryl at editor@executivetravelmag.com..