After being awarded a bar to his MC in July, Barker was wounded in the head by anti-aircraft fire in August 1917. After a short spell in the UK as an instructor, Barker's continual requests for front line service resulted in him being transferred to become a scout pilot, being offered a post with either 56 Squadron or 28 Squadron. He chose command of C Flight in the newly formed 28 Squadron, flying the Sopwith Camel that he preferred over the S.E.5s of 56 Squadron. Although Barker was reportedly not a highly skilled pilot – suffering several flying accidents during his career – he compensated for this deficiency with aggressiveness in action and highly accurate marksmanship.