It would seem that the largest single patrol loss suffered by the RFC etc on the Western Front was seven Camels of No 70 Sqn RAF lost in an action near Ecaillon, five miles east of Douai on 4 September 1918. The squadron was on temporary attachment from II Brigade and met a force of Fokker DVIIs (estimated to be 30 aeroplanes), over that part of the front before the British First Army. Another Camel was lost about an hour later at the same location.
On 26 September 1918, No 99 Sqn (
Independent Force)lost six DH9s in the course of a raid upon Thionville; two other DH9s were shot up, the observer in one being killed (pilot OK) and the pilot in another wounded (observer OK). They encountered about 30 or 40 aircraft (Fokker DVIIs ?) over Metz. Five were destroyed over Metz or during the return journey and one was destroyed upon landing.
Mannock & Co were supposed to have "slaughtered" half a dozen DFWs of a training flight early in September 1917 but felt so guilty that no claims were made (unlikely given Mannock's hatred of the enemy).