On 1 September 1939 Crowe relinquished his reserve commission[REF] and joined the Royal Air Force Volunteer Reserve as a flight lieutenant, with seniority from 13 March [REF].
On 24 September 1947 he returned to the Reserve of Air Force Officers with the rank of flight lieutenant,[REF] until finally relinquishing his commission on 27 May 1954 [REF].