On 18 May 1940, Yule took part in No. 145’s first action of the war. On patrol over Brussels, 12 Heinkel He 111's were intercepted in broken cloud and when the German bombers emerged from cover the Hurricanes attacked, Yule shooting one down. Four days later he destroyed a Junkers Ju 87. During the Battle of Britain Yule destroyed a Ju 88 and damaged three more, but on 25 October, he was himself shot down by a Messerschmitt Bf 109 in combat over Kent and was admitted to hospital with leg wounds after making a forced landing which completely wrote off his Hurricane. Yule was confirmed at the rank of pilot officer on 23 October 1940. Yule rejoined No. 145 Squadron in February 1941, but shortly afterwards was posted away to be an instructor. He helped instruct American pilots, very much under secrecy because the United States was still neutral. In early November 1941, he returned to operations with No. 501 Squadron, remaining with the unit for seven months and performing many operational sorties. In April 1942, Yule was promoted to squadron leader and awarded the Distinguished Flying Cross. His citation read: Yule assumed command of No. 66 Squadron in June 1940. While leading a squadron sweep over the Cherbourg area on 15 July 1942, Yule engaged in combat with two Focke-Wulf Fw 190s. He destroyed one, which exploded and crashed into the sea, and the other was last seen flying inland with its engine smoking. In mid November 1942, having completed his first tour, Yule was posted to general office duties and was awarded a Bar to his DFC. His citation read: In August 1943, Yule was promoted to wing commander of Detling Wing and recommenced operational flying. After leading the wing on many operational sorties, he was posted away in early March and awarded the Distinguished Service Order. His citation read:
Later career and death
Yule went on to planning duties, involving fighter wings of the 2nd Tactical Air Force in the coming Normandy invasion. He continued with these duties into 1945 and at war’s end was on a RAF Staff College course. While rehearsing for the Battle of Britain flypast over London on 11 September 1953, Yule collided with another jet aircraft. Faced with a densely populated area, Yule steered his aircraft towards Woolwich Arsenal and crash-landed between rows of buildings. Yule was killed in the crash.
