sentences:  The aircraft strayed into Bulgarian airspace, refused to land, and was shot down by two Bulgarian Air Force MiG-15 jet fighters several kilometers away from the Greek border near Petrich, Bulgaria.All seven crew and 51 passengers on board the airliner died.A United Nations plane carrying UN Secretary-General Dag Hammarskjöld and 15 others was shot down in Northern Rhodesia, now Zambia, as Hammarskjöld was traveling to negotiate a cease-fire during the Congo Crisis.