11/30/2007. Pierre George Latécoère started the design of the 521 in 1931 and construction was started at the new seaplane base at Biscarrosse, Landes, France, (43 mls, 70 km, south-west of Bordeaux) in 1933 and the construction was completed in July 1934. Powered by six 860 hp Hispano-Suiza 12Ybrs-2 water-cooled twelve-cylinders V-engines, the first flight was made by Jean Gonnord on January 10, 1935, while on November 30, 1935 the aircraft was registered as F-NORD.

On December 8, 1935, the aircraft left Biscarrosse for survey flight that brought the aircraft to Dakar and Brazil, arriving at the French Antilles on December 22. On January 13, 1936 it flew to Pensacola, Florida, USA, the following night it was flipped it on its back in a heavy storm. Disassembled the aircraft returned to France aboard the Norwegian tanker 'President Herrenschmidt'.

After rebuilt and re-engined with six 960 hp Hispano-Suiza 17Y-37 engines, the aircraft flew again on 2 August 1936 and from 1937 it was operated by Air France Transatlantique (a new subsidiary of Air France). It made at least twelve atlantic crossings before outbreak of the war in Europe. It was briefly used by Escadrille E12 of the French Navy in 1940, flying patrols over the North Atlantic. Thereafter it was stored for nearly four years, to be destroyed in 1944 by retreating German troops. View also photo 4546.