Portugal ordered its first IIIDs in 1921. Its first aircraft, modified as the F.400 and named "Lusitânia", was used for an attempt to fly across the South Atlantic and demonstrate the new aerial navigation system devised by Gago Coutinho, the navigator. The voyage started on 30 March 1922 (Flyers Day in Portugal), stopping at Las Palmas, São Vicente, Cape Verde and achieving the main navigation goal of Saint Peter and Paul Rocks, where it was lost during refuelling.[14] The journey was finished using another two standard aircraft (the second of which was immediately lost in the sea), completing the first aerial crossing of the South Atlantic, 72 days after their departure from Lisbon.