First balloon flight fatalities. 19th-century illustration of the 15 June 1785 crash of the new hybrid balloon in which Jean Francois Pilatre de Rozier and Pierre Romain were both killed. They had just departed Boulogne-sur-Mer with the intention of crossing the English Channel when eyewitnesses reported seeing a blue flame before the balloon collapsed and fell to the ground. This balloon, invented by Rozier, and on its first flight, was a hybrid of a hot-air and a gas balloon. Artwork from 'Aerostation - Aviation' (1911) by French civil engineer Max de Nansouty (1854-1913), part of the 'Les merveilles de la science' series of 1867-1891 by Louis Figuier.