The Latécoère 521 was a French six-engined double deck flying boat designed and manufactured by Pierre-Georges Latécoère. At the time of its completion, it held the distinction of being the largest aircraft to be built in France as well as one of the first large passenger aircraft capable of flying trans-Atlantic routes. First flown on 10 January 1935, the Laté 521 achieved several world records relating to payload and endurance. It was introduced to passenger service by national operator Air France, who was able to launch several previously-unattainable long distance passenger routes. As a civilian aircraft, the Laté 521 was outfitted as a luxurious airliner, providing a high level of comfort for up to 72 passengers. Shortly after the outbreak of the Second World War, the Laté 521 were taken over by the French Navy, who typically operated the type as a long distance maritime patrol aircraft. None survived the conflict due to intentional sabotage by the retreating German forces. The Laté 521 was the basis of the single Laté 522 "Ville de Saint Pierre" civil airliner, and the three Laté 523 navalized variants. During the early 1930s, French aircraft manufacturer Groupe Latécoère set about designing a new large flying boat, which was intended to perform long range flights, carrying both passengers and air mail. Around this era, France, Germany, the United Kingdom, the Soviet Union, and the United States, were endeavouring to launch ever-larger aircraft that would exceed the scale and payload capabilities of preceding aircraft and ultimately displace the ocean liner as the principal means of passenger travel. The development of such aircraft was a matter of national prestige and Latécoère quickly found support for their endeavour. The design, designated the Laté 520, was a large sesquiplane, comprising a central double-decked hull and a pair of stub wings, somewhat resembling the smaller Latécoère 300. Weighing roughly 37 tonnes when loaded and 17 tonnes empty, it was the largest aircraft to be manufactured by French industry at that time. It offered a maximum range of 2,800 miles between refuelling stops. The four inboard water cooled engines, which were mounted as tandem push-pull pairs and intended to be capable of generating up to 1,000 hp, enabled the aircraft to attain a maximum design speed of 160 mph. It was named Lieutenant de vaisseau Paris, after a highly accomplished French naval officer and record-breaking pilot of the era. In its civilian service configuration, the Laté 521 would transport a maximum of 72 passengers in luxurious conditions. However, typical trans-Atlantic services would normally only carry around 26 passengers, all of which would be upon the lower deck. Larger passenger complements could be carried on the shorter trans-Mediterranean routes for which the design had originally been envisioned to serve. On the lower level, there was a salon occupied by 20 armchairs and tables, along with six deluxe double cabins, each with its own bathroom, and seating for a further 22 passengers, a kitchen, a bar, a lavatory, and a baggage hold. Separate compartments for the wireless operator and navigator are also present on the lower deck. The more compact and narrower upper level of the hull featured seating for 18 passengers, along with a storage compartment, a second kitchen and bar, and another lavatory. For more details of development, design, operational history and variants, click here.
