Joined the Royal Air Force (RAF) Volunteer Reserve in November 1937. Two years later, with his studies nearly complete, Corbett was visiting family in British Columbia when Britain declared war on Germany on September 3, 1939. He immediately returned to England and the RAF.
After completing his training at No. 9 Advanced Flying Training School, he was posted to No. 7 Operational Training Unit at Hawarden, Cheshire, on July 7, 1940. This unit focused on one thing and one thing only: the training of Spitfire fighter pilots. A combination of personal talent and operational need meant that Corbett’s stay was short; on July 26, the young Canadian found himself reporting to No. 66 Squadron at Coltishall, Norfolk.
The squadron had already engaged the Luftwaffe in the skies above Dunkirk and was ready to “have a go at Jerry” over home turf. Although Corbett participated in a number of combat patrols, his first true combat experience came on September 9, 1940, and it was not a pleasant experience. Dodging often heavy rain showers, Pilot Officer Corbett was part of a group attacking German bombers, escorted by enemy fighters, intent on attacking London. After already damaging a Messerschmitt 109, he was positioning his aircraft for a rear attack on a bomber when he was bounced by three German fighters. With the cockpit filling with smoke and the controls jammed, he found himself in a severely damaged, uncontrolled aircraft plummeting toward the ground in a tight spiral dive. At 12,000 feet (3,658 metres), the pilot bailed out, suffering a slight injury in the process.
Corbett quickly returned to the fray, and on September 27 he and his squadron mates intercepted German bombers attacking London. In the midst of heavy British defensive fire from anti-aircraft guns below, he got a quick burst into one bomber before breaking off the attack and leaving the damaged enemy aircraft to other RAF fighters. He then selected a lone Junkers 88 as his next target, closed to within yards of the German aircraft, and opened fired. The enemy aircraft fell away, its port engine burning fiercely, but the smoke was so thick that Corbett had to break off the attack.
He had little time to enjoy his victory because his Spitfire was damaged by friendly fire when an artillery shell burst nearby, destroying one elevator and riddling the fuselage and starboard wing with shrapnel. He skillfully executed a forced landing in the London district of Orpington, emerging from his damaged but repairable Spitfire with a new-found respect for anti-aircraft gunners and a Junkers 88 claimed as destroyed. Two London bobbies who came to his assistance had witnessed the combat, and confirmed Corbett’s claim.
More combat followed, but this young man who had survived being shot down twice would not be so lucky the third time. On October 8, 1940, Pilot Officer Corbett, wearing a new watch sent by his parents as a 21st birthday gift, was climbing with his squadron to intercept yet another formation of German raiders when they were surprised by a large number of Messerschmitt 109s. In a slashing attack, Corbett and one other 66 Squadron pilot were shot down near Bayford Marches, Upchurch; neither pilot survived.