A USAF Boeing B-52G Stratofortress (58-0256) began its mission from Goldsboro-Seymour Johnson AFB, NC (GSB), carrying four Type B28RI hydrogen bombs on a Cold War airborne alert mission named Operation Chrome Dome. The flight plan took the aircraft east across the Atlantic Ocean and Mediterranean Sea towards the European borders of the Soviet Union before returning home. The lengthy flight required two mid-air refuellings over Spain. At about 10:30 am on 17 January 1966, while flying at 31,000 feet, the bomber commenced its second aerial refuelling with a USAF Boeing KC-135A Stratotanker (61-0273) out of Mor¢n Air Base in southern Spain. The planes collided, with the nozzle of the refueling boom striking the top of the B-52 fuselage, breaking a longeron and snapping off the left wing, which resulted in an explosion. All four men on the KC-135 and three of the seven men on the bomber were killed.