All status information, on every known flight in progress and every commercial plane on the ground, is transmitted from the 22 ARTCC's, (Air Route Traffic Control Centers) to an FAA Technical Center in Atlantic City and then sent by land and satellite to a DoT Systems Center. There, an array of DEC VAX super mini com- puters process the constant influx of raw data and send back an updated map across the ETMS every five minutes. Chad zoomed in on the picture of the country into the DFW ap- proach area and confirmed that the airplanes in question were not appearing on the National Airspace System data fields or dis- plays. Something was drastically wrong. "Chad, take a look here!" Another controller urgently called out. His radar monitor had more bogies than Paul's. "I lost a Delta, too, 1258." "What is it?" "37." "Shit," said Chad. "We gotta get these guys wide, they have to know what's happening." He called over to another controller. "Get on the wire, divert all traffic. Call the boss. We're closing it down." The controllers had the power to close the airport, and direct all flight operations from the tower. Air- port management wasn't always fond of their autonomy, but the tower's concern was safety at all costs. "Another one's gone," said Paul. "That's three 37's gone. Have they had a recall lately?" The ETMS operator asked the computer for a status on 737's else- where. "Chad, we're not the only ones," she said. "O'Hare and LAX have problems, too." "OK, everybody, listen up," Chad said. "Stack 'em, pack 'em and rack 'em. Use those outer markers, people. Tell them to believe their eyes. Find the 37's. Let 'em know their transponders are going. Then, bring 'em down one by one." The emergency speaker suddenly rang out. "Shit! Dive!" The captain of American 1137 ordered his plane to accelerate ground- ward for 10 seconds, descending 2500 feet, to avoid hitting an oncoming, and lost, DC-9. "Dallas, Mayday, Mayday. What the fuck's going on down there? This is worse than the freeway . . ." The emergency procedure was one they had practiced over and over, but rarely was it necessary for a full scale test. The FAA was going to be all over DFW and a dozen other airports within hours, and Chad wanted to be prepared. He ordered a formal notification to Boeing that they had identified a potentially serious malfunc- tion. Please make your emergency technical support crews avail- able immediately. Of the 100 plus flights under DFW control all 17 of the Boeing 737's disappeared from the radar screen, replaced by dozens of bogies with meaningless signatures. "Dallas, American 1137 requests emergency landing . . .we have several injured passengers who require immediate medical assist- ance." "Roger, 1137," Gatwick blurted back. "Copy, EP. Radar status?" "Nominal," said the shaken American pilot. "Good. Runway 21B. We'll be waiting."