Gran was commissioned into the Royal Flying Corps under his own name as a probationary temporary second lieutenant on 1 January 1917,[REF] confirmed in the rank and appointed a flying officer on 1 March 1917,[REF] and was posted to No. 70 Squadron, flying the Sopwith Camel on the Western Front.
He was promoted to acting-major on 10 September 1918 [REF].