No. 1 Squadron joined the 40th (Army) Wing of the RFC's Palestine Brigade on 5 October 1917. On 22 and 24 November, the squadron bombed Bireh village during the Battle of Jerusalem. The first of its 29 confirmed aerial victories, over an Albatros, occurred on 3 January 1918. By month's end, its complement of aircraft included five B.E.2s, five Martinsydes, two R.E.8s, and nine Bristol Fighters. The squadron supported the Capture of Jericho in February 1918. It carried out air raids and reconnoitred prior to the First Transjordan attack on Amman in March and prior to the Second Transjordan attack on Shunet Nimrin and Es Salt a month later; it also flew reconnaissance missions during the advance to and fighting near Es Salt and Jisr ed Damieh. By the end of March, it was equipped with 18 Bristol Fighters, which had replaced all the other types. As well as undertaking offensive operations, the Bristol Fighters served in the photo-reconnaissance role. During the last week of April 1918, the squadron moved its base forward from Mejdel to a new aerodrome outside Ramleh. Williams relinquished command in June to take over 40th Wing.