|First flight||11 September 1933|
|Primary users||French Navy
|Developed from||Short S.8 Calcutta|
A biplane of all-metal construction, with three engines mounted in nacelles between the upper and lower wings, the aircraft was a development of the Breguet S.8/2 Calcutta, which itself was a militarised licenced version of the British Short S.8 Calcutta. It was built to meet a French Navy specification for a long-range flying boat issued in 1932, competing against proposals from Latécoère (the 582), Lioré et Olivier (the unbuilt LeO H42) and Loire Aviation (the Loire 70). The first prototype made its maiden flight on 11 September 1933, with it being purchased (and an order placed for two more on 4 January 1934.
A series of small orders for production Bizertes were placed, starting with an order for three in 1934, with the last order, for 12 (nine of which were later cancelled) being placed in September 1939. In total, 37 Bizertes were built, with the last three not being completed until after the French surrender in June 1940.
In 1935 a civil version - the Breguet Br.530 Saigon - was produced.
After the first flight in September 1933, 37 aircraft were produced, which served with five squadrons of the French Navy from 1935 until 1940. Two squadrons remained in service with the Vichy Navy after the armistice, at Berre in Southern France and Karouba in Tunisia, with six aircraft each. The German Luftwaffe purchased a number of Bizertes for its Seenotdienst (Air-Sea Rescue) service in 1940, which (in addition to the three undelivered Bizertes) it used to equip a squadron based at Brest on the French Atlantic coast. When Vichy France was occupied by the Germans following the Allied invasion of North Africa in November 1942, the remaining Vichy Bizertes were taken over by the Luftwaffe, allowing further Seenotdienst units to be established at Biscarrosse and Berre. Following the Allied Invasion of Southern France in August 1944, one of the Luftwaffe Bizertes was discovered by French forces and used for communications duties until spares ran out.
- Breguet 521.01
- Breguet 521 Bizerte
- Long-range flying boat, powered by three Gnome-Rhône 14Kirs 14 cylinder two-row radial engines or three Gnome-Rhône 14N radial engines.
- Breguet 522
- Re-engined version of Breguet 521. Three 900 hp (670 kW) Hispano-Suiza 14AA radial engines. One built.
- Breguet 530 Saigon
- Civil version of the Breguet 521. Three Hispano-Suiza 12Ybr liquid-cooled inlines. Two built.
Data from The Encyclopedia of Military Aircraft
- Crew: 8
- Length: 20.48 m (67 ft 2 in)
- Wingspan: 35.18 m (115 ft 4 in)
- Height: 7.50 m (24 ft 6 in)
- Wing area: 162.6 m²  (1,750 ft²)
- Empty weight: 9,470 kg (20,878 lb)
- Loaded weight: 14,669 kg (32,271 lb )
- Max. takeoff weight: 16,600 kg (36,597 lb)
- Powerplant: 3 × Gnome-Rhone 14Kirs 14-cylinder radial engines, 671 kW (900 hp) each
- Maximum speed: 243 km/h (131 kn, 151 mph)
- Cruise speed: 200 km/h (108 kn, 124 mph )
- Range: 2,100 km (1,134 nmi, 1,305 mi)
- Service ceiling: 6,000 m (19,685 ft)
- Wing loading: 90.2 kg/m² (18.4 lb/ft²)
- Power/mass: 137 W/kg (0.0837 hp/lb)
- Climb to 2,000 m (6,560 ft): 8 min 46 sec
- Guns: 5 × 7.5 mm (.295 in) Darne machine guns
- Bombs: 300 kg (660 lb) of bombs
- Related development
- Related lists
- List of aircraft of World War II
- List of military aircraft of France
- List of seaplanes and flying boats
- Green 1968, p.6.
- Passingham Air Enthusiast March/April 2000, pp. 56–57.
- Green 1968, p.7-8.
- Passingham Air Enthusiast March/April 2000, p. 58.
- Green 1968, p.8.
- Passingham Air Enthusiast March/April 2000, pp. 59–60.
- Passingham Air EnthusiastMarch/April 2000, pp. 60–61.
- Green 1968, p.9.
- Donald 1997, p. 189.
- Jackson 2002
- Donald, David (Editor) (1997). The Encyclopedia of World Aircraft. Aerospace Publishing. p. 189. ISBN 1-85605-375-X.
- Green, William (1968). Warplanes of the Second World War, Volume Five, Flying Boats. London: Macdonald. pp. 6–9. ISBN 978-0-356-01449-4.
- Jackson, Robert, The Encyclopedia of Military Aircraft, Paragon, 2002. ISBN 0-7525-8130-9
- Passingham, Malcolm (March–April 2000). "From Calcutta to Bizerte: The Breguet 521 Flying Boat". Air Enthusiast (86): pp. 56–61. ISSN 0143-5450.
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