He claimed his first aerial victory over a Vickers Wellington bomber, among the 12 shot down in the aerial battles of the Heligoland Bight on 18 December 1939. His successful co-ordination of a range of different units and aircraft was effective and forced a fundamental change in air strategy for the Royal Air Force (RAF) in the first year of the war, as they abandoned unescorted bomber missions. He claimed his only other victory, a Bristol Blenheim, over the North Sea on 27 December 1939.