For the last 5 days since the launch of the German offensive, British forces have gradually been forced back. In an effort to maintain the line, the air forces have increasingly been diverted into ground attack missions against German troops.
Reinforcements have been drafted in from every part of the front as losses have been high and many Squadrons have had to abandon their aerodromes and aircraft to the advance. In all 27 squadrons engaged in ground attack including reinforcements from 1 Brigade (all squadrons), II Brigade (1, 19, 20 and 57), and V Brigade (5 Naval, 54 and 84), This was the largest concentration of squadrons in the war to date, though not necessarily the largest number of aircraft as many were under strength. H
Aircraft also played a significant role in the defence of Roye in the 5th Army sector as squadrons carried out ground attacks. Curiously, despite the significant nature of the fighting, there was little in the way of German air activity in this sector. The Germans remained reticent about committing their aircraft over the lines as they were difficult to replace. The Germans too had suffered high casualties and were also suffering from supply problems as their aerodrome were now well behind the front and the liaison between squadrons and ground units began to break down.
This was not so true in the 3rd Army sector and the reinforcements in particular suffered, possibly due to unfamiliarity. 1 Squadron suffered three casualties and 19 Squadron two in the afternoon when they were attacked by Jasta 26:
1 Squadron’s 2nd Lieutenant Allan MacNab Denovan in SE5a B511, 2nd Lieutenant William Mudie Ronald Gray in SE5a B641, and Lieutenant Arthur Hollis in SE5a B643 were all shot down. Denovan was killed and the others taken prisoner. 2nd Lieutenant Fernley Winter Hainsby in Sopwith Dolphin C3790 and 2nd Lieutenant Edward John Blyth in Sopwith Dolphin C3793 both from 19 Squadron were also shot down and killed.
Captain Herbert James Hamilton in SE5a B32 and Lieutenant Douglas Maitland Bissett in SE5a B8265 were both badly shot up but escaped back over the lines.
In the evening 58, 83, 101 and 102 Squadrons carried out the heaviest night bombing of the war so far dropping 24 tons of bombs on Baupame in an effort to disrupt enemy reinforcements.