The German Spring Offensive began just over a month later, and he flew intensively, many operational flights consisting of highly dangerous ground strafing and bombing. Yeates was posted to 80 Sqn on 9 August from 46 Sqn and joined B Flight, and left the Squadron on 31 August after the move to a new airfield at Allonville. He was invalided back to England suffering from Flying Sickness D (for Debility), brought about by the strain and conditions of constant flying. He was given one month's sick leave, further extended to 7 November 1918, when he was transferred to TDS Fairlop as an assistant flying instructor, being finally discharged on 23 May 1919.