by Jonathan M. Stern
Tower Controller is a product of Aviation Simulations, Inc., a joint venture of BAO, Ltd., and Wesson International. In September of 1994, I had the opportunity to try a pre-release version of the program, and BAO, Ltd., personnel were kind enough to answer some of my questions about the program. Accordingly, it is possible that some of the functions, features, and operations of Tower Controller will be different than what I describe here.
Tower Controller is a Windows-based program that simulates the jobs of the local (or tower) and ground air traffic controller. The ground controller is responsible for providing information and instructions to get the airplanes from their gates to the runways and vice-versa. The local controller is responsible for sequencing and spacing arriving and departing aircraft. Both of these jobs are performed from the control tower cab, the glass booth that sits atop a control tower.
Tower Controller is not perfect, but it is of sufficient fidelity to give the user a real taste of what it is like to be a tower controller, particularly the local control function. As you might imagine, the tower at a busy airport such as Chicago O'Hare or Washington National, two of the airports simulated in the program, is a hectic — sometimes frenzied — place. Keeping track of the operations of two or three airplanes per minute can make one's hair stand on end. Experienced controllers typically don't think of each airplane as 100 or more human lives; thinking in such terms would make the job unbearable.
Much like a pilot, the tower controller must keep his or her head "on a swivel." The traffic situation is constantly changing, and the tower controller needs to keep track of where all the airplanes are all the time. Tower Controller provides several tools to accomplish this goal. First, there is an out-the-glass display that can be selected in a variety of ways to provide a 360° view. Second, there is a BRITE scope, which is a radar repeater that shows a bird's-eye view of the area surrounding the airport. Arriving and departing aircraft are depicted along with data tags that show aircraft identification, altitude, and speed. Third, Tower Controller provides Airport Surface Detection Equipment, or ASDE for short, a radar display of the airport and the aircraft taxiing on the airport surface.
There are several different ways to scroll the view out of the tower cab. A small compass rose with a pointer appears on screen, and the computer's mouse can be used to select the viewing direction. Alternatively, clockwise and counterclockwise arrows can be pushed with the mouse to rotate the view. The problem with this method of viewing is that it provides less control than a human being actually has when standing in a tower, because it does not provide simultaneous control of up and down panning. While panning is available with the program, it is quite difficult to scroll and pan simultaneously to the point in the sky where an aircraft is flying. For this reason, I found the "track" mode to be the most useful way to control the out-the-glass view.
The track mode automatically sets and changes the out-the-glass view so that the aircraft being tracked is constantly centered on the display (see Figure 20.1). The aircraft being tracked can be changed by clicking on its corresponding display on the BRITE or ASDE scopes or by clicking on the aircraft's flight progress strip. Real controllers keep track of their aircraft in much the same way, scanning from one aircraft under their control to another. Other than for the purpose of scanning a runway or departure path to ensure it is clear prior to authorizing its use, there is little purpose in looking any place other than where your traffic is flying.
Figure 20.1. This aircraft is being viewed in track mode.
Three airports come standard with Tower Controller: Chicago O'Hare, Washington National, and March, Canada. March is animated while National and O'Hare are "photo-realistic." The graphics at March tend to be more fluid, and some features not available at the photo-realistic airports can be activated here. For example, for aircraft just a little bit beyond eye's range, the "binocular view" can be used. One tool available to Tower Controller users that I never had when I was an air traffic controller at Washington National Airport is the "super binocular" view, which provides a tracking close-up of the selected airplane. Finally, to get the pilot's perspective, the Tower Controller user can select the pilot's view at March.
If your computer is equipped with a Sound Blaster-compatible card, you can listen to the pilots over the radio — at least at O'Hare and March. The audio feature was not yet working at Washington National when I tested the program. Instructions to the aircraft are given through a series of keyboard commands. For example, to instruct United 1421 to enter right base for runway 22L, one would type 1421/ERB22L. After several sessions, the commands start to come naturally. "What's that?" The pilot of the Cessna Citation didn't understand your instructions. Believe me, that happens in real life too.
The level of difficulty is controlled by varying the rate of departures and arrivals and selecting a more or less difficult airport. Washington National has three runways (usable in six directions), while O'Hare has seven runways (usable in 14 directions). If the volume of traffic is starting to get to you, either take a deep breath and keep going or push the coffee cup icon and head to the break room.
Tower Controller is unrealistic in a number of respects. First, arrivals come from all directions. In actuality, the TRACON would be radar vectoring the arriving aircraft onto the final approach courses, generally from one direction. For example, at Washington National, the airport operates in either a north or a south operation. In a north operation, arriving aircraft are radar vectored from the south to the north over the Potomac River. The tower then assigns these aircraft to runways 3, 33, and 36. Runways 15, 18, and 21 are generally not used during a north operation. Tower Controller's operation more closely resembles that of a VFR tower, but one would not find the assortment of large and heavy jet aircraft used in Tower Controller at such an airport.
Second, the airplanes in Tower Controller sometimes taxi onto the runway without an appropriate clearance. In real life, when an airplane is instructed to taxi to a runway and no restriction is stated, the aircraft is authorized to cross any runway along its taxi path but is not authorized to taxi onto the assigned runway. With Tower Controller, the airplanes frequently violate this rule, and this leads to serious collision hazards.
Third, airplanes that have taxied to the departure runway and are awaiting takeoff clearance do not call to remind you. Thirty minutes can go by, and the pilot still will not call to tell you that he is waiting for takeoff clearance. I can assure you that this is most unrealistic. Nonetheless, this means you must keep close track of your departures even before they take the runway.
Tower Controller tracks your performance and moves you up the ladder toward the full performance level, which carries with it a higher salary than that of the more junior controllers.
While Tower Controller does not provide quite the same experience as working traffic in a real tower, it goes a long way toward giving a novice a taste of that experience.