Ridley went on to drive down a Pfalz D.III on 2 May, destroy a Fokker Dr.I on 6 May, and drive down another on 30 June. His 11th and final victory occurred on 4 July 1918, with the driving down of a Fokker D.VII near Foucaucourt. On 10 July his aircraft suffered an engine failure over enemy lines, forcing him to land, and he was held as a prisoner of war until after the armistice in November 1918.