riding the beam

There are several ways you can navigate while flying an airplane. The first and simplest is called pilotage. That's how things used to be done in the olden days. Pilots made their way by picking out familiar landmarks on the ground, visually. That was one method I used when I flew my first cross-country to General Fox Airport in Lancaster. I took off and turned west; spotted Southern California Logistics Airport in Victorville, ten miles away; flew over that; espied the dry lake at El Mirage a few miles farther on; overflew that; descried the water tank on the hillside a few miles beyond that; and once I'd passed it, General Fox was in sight. The second way, and the most modern, is by GPS. "GPS," as even the most technologically dumbfounded of you should know, stands for "Global Positioning System." They're basically devices which gather data from orbiting satellites and use it to triangulate your position on the Earth's surface. The nice thing about the aviation GPS system is that the manufacturers have thoughtfully included all relevant data on the virtual map that you might need to know: airspace boundaries, obstacles, prohibited areas, whatever. Moreover, navigation is absurdly simple with a GPS. You can enter an airport or a waypoint and a purple line will appear on the screen, going straight from your airplane to that destination. You need merely follow that purple line and you'll get there. Fast going out of style, but far more reliable than pilotage (and essential for instrument work), is the VOR. "VOR" stands for "VHF Omnidirectional Range." VORs take the form of white, pointy buildings. Harold says they look like upside-down ice cream cones. They are located at airports and out in the middle of nowhere, and emit a constant signal in the VHF range. Special antennae on the tail of an airplane pick up this signal, and an indicator in the cockpit tells the pilot where the signal's coming from. (If you're equipped with DME, or distance-measuring equipment, your indicator also computes the straight-line distance to the VOR station). VORs shoot these signals in all directions, through all 360 degrees of the compass. That means, if you're within range of the signal (generally 50 miles or less, depending on how high you are) you can tune your instruments to that particular VOR's frequency. Then you can do whatever the heck you want with it: verify your distance away from it, use it to triangulate your exact position, or even navigate by it. The latter is known as "riding the beam." Thursday, Harold and I took off from Apple Valley Airport with the express idea of getting a little VOR navigation practice in. We were in luck. There are VORs scattered throughout the lower 48 states, but this being Southern California, there are VORs all over the friggin' place. There was one at Southern California Logistics Airport in Victorville, ten miles west; another one at Palmdale, about 50 miles west or so; and a third at Barstow-Daggett, about 26 miles or so northeast. So, we flew up to 6,000 feet MSL (about four thousand feet off the ground, the highest I've ever flown) and began fiddling with dials and knobs. This is the instrument that we used, the VOR indicator: This isn't quite what the VOR indicator in the cockpit of our 1974 Cessna looks like, but it'll do. It's got all the basic elements. The rotating course card (A) is set up with compass points: north, south, east, west, and everything in between. In terms of VOR navigation, these are called radials. North (360 degrees) is a radial; south (180°) is a radial, as is west (270°), east (090°), and all the other points. You rotate the course card with (B) the omni-bearing selector. The to-from indicator (C) indicates whether the radial you're on (as indicated by the little arrow at the top of the indicator) is the heading TO the VOR installation, or FROM the VOR installation. And of course, the all-important course deviation indicator (D), or CDI, tells you whether you're actually on course or not. If you are, the needle is centered. If you're not, it swerves to the left or right. Each one of those little dots in the middle of the VOR indicator means a course deviation or two degrees. If you're following a radial directly to the VOR station (flying the same path as the signal), and the CDI is two dots to the left of center, that means you're four degrees off course and should bear left. If you're feeling confused by this, don't be alarmed. You're in the same boat with 100% of the human race. NOBODY understands VOR navigation when they first hear about it. VORs are depicted on aerial charts like this: The Avenal VORTAC ("TAC" being short for "TACAN" a military-grade navigation system sometimes paired with a VOR) is right in the middle of that big circle with all the compass points on it. Its frequency is 117.1 (says so in that little rectangular box near the center). Let's say you're within range of the VORTAC and want to make use of it. First, you tune your navigation equipment to 117.1. Also tune your communications equipment in, and listen for the identification code. You do this to make sure that the VOR is working and transmitting properly, and that you're actually tuning into the right one. Once you've verified the VOR's identity, then you can rotate your rotating course card using the OBS knob until your CDI homes in on the signal and centers itself. Once it's done that, take a close look at your VOR indicator. If it says "TO" and the number up at the top is 345 degrees (as indicated in the picture above) then, if you were to turn to a heading of 345°, then you'd be heading straight toward the VOR. You are picking up the station's outgoing 165° radial. (You see, 345 minus 180 is 165. You have to keep a heading of 345° to go to the station; and the signal from the station is following a heading of 165° to go in the opposite direction, to reach you.) I'm going to stop explaining here because I have a feeling that you're as confused as an ostrich in a diamond mine. I will merely add that VOR indicators tell you what direction a VOR signal is coming from—not what heading you're on. Therefore, you want to be very careful not to confuse the heading TO the VOR with the heading AWAY from it, or else you'll try to correct your course and inadvertently get further off it (known as "reverse sensing"). Quick recap:

• WHAT - VOR, or VHF omnidirectional range, a station that emits a constant VHF signal to all points of the compass.
• WHERE - All over the continental United States.
• WHY - They are handy, if slightly outdated, navigational tools.
• WHO - Pilots use them when they get tired of GPS systems or can't see the ground.
• HOW - Find out the frequency of a particular VOR you want to use. Tune your navigation equipment in the cockpit to that frequency. Twiddle the knob until the needle on the indicator centers itself. Then read the heading on the course card at the top of the indicator window. If the to-from indicator says "TO," then you would follow that heading to get to the VOR. If the indicator says "FROM" then you are going the same direction as the outbound VHF signal; the heading back to the VOR is the reciprocal of that heading (the heading number minus 180 degrees).
• REMEMBER - The VOR indicator (when the needle is centered) does not tell you what course you're on. It tells you which direction the beam from the VOR station is coming from/going to.

Needless to say, it took a while for me to get all this down. The concept is still a mite fuzzy in my mind. I've likely made a few glaring mistakes in explaining it. If I have, I crave your indulgence. I'm still learning, after all. Anyway, Harold and I wandered about the sky, picking up various VOR signals, intercepting them in mid-air, and following them for short distances. We even rode on a "Victor airway," a sort of highway in the sky formed by VOR signals between airports. It ran from Palmdale to Palm Springs, about a hundred miles away. Harold and I detected the signal, moved the airplane onto an intercept course, and then N42126 smoothly merged onto the airway as though on an invisible on-ramp. Cool. To me, this is one of the neatest things about flying. The military may have its radar and high-tech wizardry, but general aviation pilots have VORs. Sure, they're antediluvian. Yeah, they make you think in order to use them properly. But to me, those are both pluses. I like old stuff, as you probably know by now. (Vintage warplanes and Hanna-Barbera cartoons spring to mind.) I don't like fancy electronics. I hate camera phones and Blackberries, iPhones and intuitive user interfaces. I like it when a device doesn't do all the work for you. I like it when the thinking is ultimately left up to the operator. The VHF omnidirectional range is just such a device. It'll give you information, but deciphering and using that information is your job. If you mess up, it's your own fault. The human race has forgotten that. GA pilots haven't. As a boy, I loved visiting museums where they had old airplane control panels set up for me to fiddle with. Pulling levers, pushing buttons, flipping switches...I couldn't get enough. I'd pretend I was warming the old bird up for launch, activating each system one by one, rattling off imaginary jargon to my invisible copilot. Using VOR equipment brings out that kid in me once again. Today, during a solo practice session, I switched on the nav equipment, punched a few buttons, then started twiddling the OBS knob until I homed in on the Barstow-Daggett VOR. I centered the needle, then turned until I was following a heading of 40 degrees, paralleling the station's outgoing 220° radial. I was riding the beam.