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Happened as dated, per en.wikipedia.org: "Construction of six prototypes began in February 1965, with the first flight from Toulouse on 2 March 1969."
The Smithsonian’s Concorde record confirms that Concorde 001, assembled at Toulouse, took to the air on 2 March 1969 with French test pilot André Turcat at the controls.[1]
The museum on Concorde’s British assembly site at Filton, giving the programme’s Anglo-French history alongside the French prototype’s first flight.[1]
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