Air Traffic Controllers have been working with moving maps since the 1940s. The map, of course, doesn't actually move; instead, the radar targets cross the radarscope, presenting a close-to-real-time display of the overall air-traffic picture.
Controllers used to non-radar en route or terminal facilities drooled when radar first came into the outlying neighborhoods in the 1960s. They soon discovered, however -- as every radar student discovers -- that having the picture right in front of your nose can be blinding.
Radar instructors get a secret glee from watching the hotshot student who breezed through the non-radar portion of the training lock up in terror the first time the scope gets saturated with users. More information leads to information overload. Sometimes only a little knowlegde is, indeed, a good thing.
The trick in ATC radar is to learn to filter out the garbage that clouds the true picture. And that begins with setting up the scope itself. When a controller is ready to take a break, another controller plugs into the position and monitors the operation. When she thinks she has the "flick" (technical term for picture; coined by the late Jean Shepherd in 1963), she says, "Whaddya got?" The controller in the hot seat then stands as the relieving controllers drops in. The outgoing controller briefs the relief, lingers for a minute to review the checklist (now a voice-recorded procedure to verify that no one's cheating), then bolts for the break room to watch the last half of Oprah.
Each controller sets up the scope according to taste. It's like taking the controls of an airplane. When your buddy says, "You want to take it?" you slide your seat forward, adjust the panel lights to your liking, and motor on. Different strokes for different yokes. Depending on the type of scope (D-BRITE in the tower), the radar controller adjusts a variety of items to set the scope to a familiar comfort level. The scope must be set so its alignment matches predetermined radar reflectors or fixed beacon transponders (parrots -- ever wonder why they say "squawk"?) It's like checking your VORs to make sure they're within tolerance before launching IFR.
Sometimes you remember, and sometimes you run a VOT check after the last approach broke out four miles west of the airport. Controllers are required to check scope alignment. It doesn't always get accomplished but it's usually not a problem.
About the worst I ever saw was a radar map distorting, but I'd always worked with good radar technicians who kept the old scopes (real old) tuned. Other tuning items are a matter of taste.
One controller might like a slightly darker gain than another might choose. Some controllers prefer to expand the range of the scope out further than others do. Let's say an approach control facility owns airspace out to 40 miles. Facility directives may require the controller to look out 50 miles in order to spot arrivals. Some controllers want to look as far as the scope will reach to spot the incoming flow and prepare. Personally, when I was controlling, I kept the picture as tight as possible; all that inbound stuff just added unnecessary items. I figured the arrivals were coming no matter what, so why get all sweaty watching the targets approach? I wasn't much of a preplanner; mostly I reacted and corrected.
Range mark adjustment is a matter of hotly disputed taste on approach radarscopes. Controllers select how many range marks they want to see or how intense they should appear (the rings, not the controllers). Concentric rings encircle the main bang. The main bang is the site of the radar antenna on the scope, usually located in the center of the scope, but not always. Main bangs should disappear with digital technology. Center scopes don't have them because they operate off several antenna sites. One controller might select 10-mile range marks, while the next guy wants a tighter picture with five-mile rings. Two-mile range marks are also available but it's like vectoring through a spider web. Mostly the two-mile rings are reserved for the ancient (and almost-lost) art of ASR approaches. Range marks can be ignored completely.
Like pilots, radar controllers will all agree to disagree on personal preferences when it comes to setting up the screens. Both, however, learn that the screen might be the center of the big picture, but both also must maintain a scan on the peripherals. For the controller, it's the changing weather reports, altimeter trends, winds, traffic flow messages, flight plan amendments, and break rotations. For the pilot, the scan must leave the pretty TV screen and take in the engine gauges, warning lights, and the passing scenery.
If you ever have a chance to visit a busy radar facility, watch a controller work for a while. Notice posture. When traffic complexity increases, many will hunch over, drilling their focus into a tighter and tighter beam until the unskilled controller loses the big flick. At that point, a good instructor or supervisor will say, "Lean back, take a deep breath and get the picture back."
Guess what happens when a GPS-oriented pilot gets too focused in a tight IFR environment? Tunnel vision.
So, if you find your nose on the scope, lean back, and take a deep breath. It only takes a few seconds, but it unlocks the brain allowing you to swim easily through the clag.
Godfrey mixes his love of flying with a love of music. He is an instrument-rated private pilot who flies a 1974 Bellanca Viking based at Palomar airport just north of San Diego, Calif. He composes music for commercials, films, broadcast and corporate media and has composed and produced thousands of music tracks for America's largest advertisers. He'll be playing bass with Eugene Levy and Catherine O'Hara in "A Mighty Wind" -- Chris Guest's spoof of folk music due out in the spring of '03. Find out more at Joe's website. In addition to writing for AVweb, Joe has written for AOPA Pilot, The Aviation Consumer, Twin and Turbine and IFR
magazines. He is a pilot and ex-director of Angel
Flight West, a nonprofit organization that uses private airplanes to fly
indigent medical patients. He is married and lives in Leucadia, Calif. So far,
Joe is the only AVweb staff member who has logged time with Ella Fitzgerald and
conducted the London Symphony.