Over the years, I have visited various air route traffic control centers, approach control radar rooms, and tower cabs. I have come away from each visit having learned something that improved my day-to-day flying.
The most dramatic example was a series of visits to approach control facilities in several major metropolitan areas, including Dallas-Ft. Worth, San Francisco-San Jose, and the Los Angeles basin. I was writing a series of stories for AOPA Pilot magazine about standard arrival and departure routes that controllers have mapped out for IFR aircraft inbound to and outbound from the airports in the regions. The series was called "Metrocomplexity," and for good reason. The centerpiece of each story was a two-page plan-view graphic of the metropolitan area, with all of the standard aircraft arrival and departure routes and altitudes depicted for each airport in the region. In each instance, the graphic showed a formidable tangle of invisible highways in the sky snaking to and from the many airports.
The point of the series was simple: If you fly into and out of these areas, you will be given a clearance to fly one of these routes and altitudes. Which route you are assigned depends on where you are coming from and going to. Even more important, the series showed VFR pilots who fly within each of the metropolitan areas where and at what altitudes they can expect to encounter heavy traffic.
Compiling the information involved spending long hours with controllers who explained their system of using fixes, usually VORs positioned around the perimeter of the metro region, as arrival and departure "gates" to the airports within the region. Inbound traffic is funneled to the perimeter fixes. The route from the arrival fix to the destination airport may then take a number of twists and turns and involve a series of step-down altitudes. Departing aircraft may follow completely different routes and step-up altitudes to the departure gate fixes.
Why is the system so complex? Because controllers have to consider a number of factors when designing arrival and departure routes, including traffic flow from the other airports, and prevailing winds and active runways.
Designing standard routes in busy air traffic areas relieves controllers of having to come up with a custom route for each arriving or departing aircraft. That would be inefficient at best, and unsafe at worst. So, controllers in major metropolitan areas have this tool that they use every day to keep air traffic moving with minimum delays and maximum safety. The interesting thing about it-and the reason AOPA Pilot published the series of "Metrocomplexity" articles and graphics-is that this amazingly complex but remarkably efficient system is largely unknown to VFR pilots.
(Subsequent to the series, the National Oceanic and Atmospheric Administration began publishing VFR flyway routes on the reverse side of VFR terminal area charts. The flyway graphic shows primary IFR arrival and departure routes in the terminal area.)
That's an extreme example of what goes on behind the voice we hear when we talk to an air traffic controller. It's not something we learn from reading Part 91, which covers general operating and flight rules, in the federal aviation regulations or from reading the Aeronautical Information Manual sections on air traffic control and air traffic procedures. It's also a good example of the kind of useful information we can glean from visiting our friendly local ATC facility.
Unless you live and fly in a major metropolitan area, you won't find the level of sophisticated ATC route and altitude coordination exemplified in that "Metrocomplexity" series. But every ATC facility, no matter how small, has adopted rules and procedures that dictate how controllers manage traffic. Knowing what those "local" rules and procedures are can be a big help in your flying.
This fact was brought home to me once again on a recent visit to the control tower at my home field, a Class D airport located just outside and under the Class C airspace surrounding a big airport with an approach control facility. Pilots in the area talk to approach control when transitioning the Class C airspace, when flying VFR and requesting radar traffic advisories, or when flying IFR to my home field.
During my visit, I learned an important fact about coordination between the tower and approach control. Normally, before a controller instructs a pilot to switch frequencies to the next controller, he alerts that controller about the impending traffic. Apparently, our approach control does not give a verbal heads-up to the tower prior to handing off an inbound VFR pilot they are working. The tower controller first learns of the arrival when the pilot makes the initial radio call to the tower.
So what's the big deal? Apparently it's not a safety issue, but it does change the way I communicate with the tower when I make my initial call after being handed off by approach control. Now I know to assume that the tower controller is learning about my arrival for the first time, instead of being prepared for my call.
Instead of an abbreviated initial communication, I now provide the complete slate of information-aircraft type, full call sign, position, altitude, ATIS information code, and intentions-on my initial call to the tower. That way they know immediately where I am and who I am, which means they can do a better job of separating and coordinating traffic. In short, learning how approach control and the tower coordinate has changed the way I communicate.
This is a small example of how a tour of an ATC facility can influence the way you fly. Each time you visit you'll learn something about how and why controllers do what they do. You'll be a better pilot for it.
For the telephone number of your local ATC facility, see p.1-27 of the 1999 edition of AOPA's Airport Directory or the Airport/Facility Directory.
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