Events in the year 1973 in Bulgaria. Incumbents General Secretaries of the Bulgarian Communist Party: Todor Zhivkov Chairmen of the Council of Ministers: Stanko Todorov Events 3 March – Balkan Bulgarian Airlines Flight 307, a scheduled international passenger flight from Sofia to Moscow, crashed on its final approach to Moscow's Sheremetyevo Airport killing all 25 passengers and crew on board. Sports References 1970s in Bulgaria Years of the 20th century in Bulgaria Bulgaria