[1] After working in the Post Office between the wars, he was recalled to the Royal Air Force in early 1940.

He originally joined the 2/24th Battalion, London Regiment, of the Territorial Force and became a sergeant, the rank he held when he first entered a theatre of war on 25 June 1916.

[2][3] He was then commissioned as a second lieutenant in the 17th Battalion, London Regiment,[3] and was attached to the Royal Flying Corps from 1917.

The two-seater "Brisfit" had a maximum speed of 123 mph, which made it as fast as or faster than most enemy fighters, and was manoeuvrable to boot.

Gass and Atkey destroyed five of the attackers, sending two of them down in burning meteors of falling wreckage.

[1] In August, Gass was teamed with Lieutenant John Everard Gurdon, who had been the pilot of the other Brisfit on 7 May.

[8] Gass ceased to be actively employed by the RAF on 11 April 1919,[9] and relinquished his Territorial commission in 17th Battalion, London Regiment on 30 September 1921.

[10] He lived in South London after the war, the address given for despatch of his campaign medals was 95 Flood Street, Chelsea.

[18] With the Second World War escalating, Gass was recommissioned as a pilot officer in the Administrative and Special Duties Branch, RAF Volunteer Reserve (RAFVR), on 8 January 1940.

[19] He was promoted war substantive flying officer on 7 September,[20] and confirmed in that rank on 8 January 1941.