Took off from Debden on a training flight. Aircraft crashed in a flying accident near Almondesbury, Gloucestershire, England.
Previous to joining the RCAF, Sergeant Cotnam had been employed by the Royal Bank of Canada. He joined the bank in 1937 in his hometown of Pembroke, Ontario and also served at the Brockville, Ontario branch before moving to the Mount Royal, Quebec branch until his enlistment in December 1940
Sergeant Cotnam was cousin to Flying Officer Royden Leslie Cotnam (RCAF), killed 1945-04-08 over Italy in Spitfire MK 951.