While returning his Snipe to an aircraft depot, he crossed enemy lines at 21,000  feet above the Forêt de Mormal. He attacked an enemy Rumpler two-seater which broke up, its crew escaping by parachute (the aircraft was of "FAA 227", Observer Lt. Oskar Wattenburg killed). By his own admission, he was careless and was bounced by a formation of Fokker D.VIIs of "Jagdgruppe 12", consisting of "Jasta 24" and "Jasta 44". In a descending battle against 15 or more enemy machines. The dogfight took place immediately above the lines of the Canadian Corps. Severely wounded and bleeding profusely, Barker force-landed inside Allied lines, his life being saved by the men of an RAF Kite Balloon Section who transported him to a field dressing station. The fuselage of his Snipe aircraft was recovered from the battlefield and is preserved at the Canadian War Museum, Ottawa, Ontario.