1917 began with Germany once more assuming control of the air, epitomized by the exploits of the fighter ace, Manfred von Richtofen, known as the Red Baron. The nadir was ‘bloody April’, when von Richtofen’s squadron alone shot down 80 Allied planes. But then, as often before in the air war, technological innovation produced a rapid reversal of fortunes: the British Sopwith Tripalne, and French Spad S-XIII, each with two forward facing machine guns, proved more effective than the latest German upgrades. The Canadian Black Flight squadron shot down 86 German planes in June and July for the loss of three. The summer of 1917 saw the adoption of ground attack – strafing enemy targets from low-flying planes. Introduced by the Allies, but quickly emulated by the Germans, it was a highly effective tactic, but loss rates of ground attack aircraft were extremely high.