Crabb was born in Delhi, Ontario, Canada. He served in 92 Squadron under the command of fellow ace and future Air Marshal Arthur Coningham. Crabb flew a Royal Aircraft Factory SE.5a to score all six of his victories. They took place between 22 July and 29 October 1918. Crabb downed five German Fokker D.VII fighters and a DFW reconnaissance plane; the latter kill was shared with fellow ace Thomas Stanley Horry and another pilot.

Crabb was awarded a Distinguished Flying Cross on 8 February 1919. After World War I, he was an aviation pioneer and bush pilot. . He barnstormed. He flew air mail from Boston and New York to Detroit during the 1920s. In the early 1930s, he was the first pilot hired by the U.S. Forest Service in Maine.

Crabb returned to duty for World War II as a major, joining the U.S. Army Air Corps and serving in Training Command. After his discharge in 1945, he returned to his civilian flying job. He retired as Chief Pilot with the Forest Service at age 65, circa 1964. He continued to fly as a commercial pilot until about 1971.

 

Reference

Above the Trenches: a Complete Record of the Fighter Aces and Units of the British Empire Air Forces 1915-1920. Christopher F. Shores, Norman L. R. Franks, Russell Guest. Grub Street, 1990. ISBN 0-948817-19-4, 9780948817199.