Two jets collide in mid-air over Zagreb, Yugoslavia, killing 176 people on this day in 1976. Errors by an air-traffic controller led to this deadly collision.
During the Cold War, flights between Europe and the Far East were routed around the nations of the Soviet bloc. This made the Zagreb air-traffic control region, in non-aligned Yugoslavia, one of the busiest in the world. Still, it had a staff of only 30 people. Because it lacked sophisticated technology, Zagreb air-traffic control relied on pilots transmitting their positions to controllers so that they could chart planes’ progress. Ideally, the controllers would have been able to track planes themselves using radar.
British Airways Flight 476 left Heathrow Airport in London for Istanbul, Turkey, at 9:30 a.m. The Trident 3B was carrying 54 passengers and eight crew members. As the flight reached German air space, an Inex charter airline flight took off from Split on the Yugoslavian coast carrying 108 West German passengers returning to Cologne from a holiday. Both planes were on course to go through the Zagreb region.
Meanwhile, Zagreb’s air-traffic control staff was working shorthanded because one of the controllers was late for work. Gradimir Tasic was in charge of getting the planes through the area. Tasic, the youngest controller on duty, was working his third straight 12-hour day and his assistant was not present. Two other factors were critical in this disaster: The British Trident jet was flying into the sunlight and thus had no opportunity to see the DC-9 directly and Tasic was speaking Croatian to the Inex flight, leaving the English-speaking British pilot in the dark as to what was being said.
The left wing of the Inex DC-9 struck the cockpit of the Trident, killing the British Airways pilots instantly. When the DC-9’s wing broke off, both planes were sent spiraling to the ground. They landed about 4 miles apart, near the town of Vrbovec, 16 miles northeast of Zagreb. All 176 people on the two planes died.
After the ensuing investigation, five air-traffic controllers and two supervisors were charged with criminal negligence. Tasic, however, was the only one ultimately brought to trial. He received a seven-year prison sentence but was later released after an international outcry by air-traffic controllers.