The Italian Caproni Ca.4 of 1917 was another successful design and entered service with the Italian air force as a heavy bomber in 1918. Many further variants were produced, both during and after the war. Caproni later re-numbered many of these variants as new types, including the Ca.48 airliner. In Italy's first commercial aviation disaster and one of the earliest – and, at the time, deadliest – airliner accidents, a Ca.48 crashed while flying over Verona, Italy, on August 2, 1919, killing everyone on board (between 14 and 17 people). The unsuccessful Caproni Ca.60 prototype transatlantic seaplane had three sets of triplane wings taken from the Ca.4, making nine wings in all, and is generally classified as a multiplane.