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THE AIR CONTROLLERS. From the moment he asks permission to nose his jet away from the ramp, the pilot—however silvery his hair and steady his hand—must work in close partnership with an individual who is usually a decade or two his junior and may be as outwardly nervous as the pilot is calm. As a group, air controllers are intense and self-confident men (their ranks include few women) who are polished professionals. Day after day, unheard by the passengers riding in the sky, controllers spot pilots who have strayed into trouble and direct them to safety. A disaster could occur during even the most mundane procedure—beginning with taxiing out to the end of the runway, as Tenerife grimly demonstrated.
Precise communication becomes vitally important. To reduce the risk of misunderstanding between tower and cockpit, a controller is forbidden to tell a pilot to "hold for takeoff." The mere mention of "takeoff" could trigger a response in the mind of the pilot and cause him to throw the throttles open prematurely. The correct command: "Taxi into position and hold."
To help the pilot get the plane to the end of the runway, controllers at ten major airports around the country are equipped with special ground-sweeping radar designed to penetrate the kind of haze that obscured the vision of the KLM and Pan Am pilots last week. During the next five years, 30 more American airports are due to receive the new radar, which still needs to be made more reliable.
When the controller in the tower is sure that the runway is safe, he gives the command to go: "Eastern 158, cleared for takeoff." Soon after the jet leaves the ground, another technician in the station, known as departure control, picks up the jet on radar and guides it out of the general area of the airport. Next, a controller in one of the 20 air-route traffic control centers that blanket the country takes over responsibility, monitors the jet through his section of the sky, and then hands it on to the adjoining control center.
As pilot and controllers, talking by radio, guide the jet to its destination, they are helped by some highly sophisticated warning and navigational devices that in recent years have greatly helped to improve the record of flight safety. Every commercial jet—and every private aircraft that operates at altitudes over 18,000 ft.—is equipped with a "transponder," in effect a miniature radio station that sends out the flight number and altitude. These data appear, neatly boxed, on the greenish radar screen of the controller. As the plane moves through the air, the tiny box proceeds by tiny hops across the screen. A pilot can attract the attention of a controller by making his flight data brighten, as though a tiny supernova had flared on the radar.
In some better-equipped centers (e.g., Fort Worth, Denver, Kansas City), a computer is also keeping its unblinking eye on the action. If two of the little boxes come within two minutes of each other on a collision course, the computer, keeping track of the heading and speed, makes both data blocks start blinking to alert the controller.