No. 4 Squadron, Australian Flying Corps

4 Squadron, the last Australian Flying Corp (AFC) Squadron to be formed during the First World War, was established at Point Cook, Victoria, in late October 1916. Fully mobilised by 10 January 1917, the unit embarked for England on 17 January, arriving at Plymouth on 27 March, and was sent for training to Castle Bromwich, near Birmingham. After familiarisation with a variety of aircraft, the squadron was equipped with Sopwith Camel fighters. In the United Kingdom the squadron was designated 71 (Australian) Squadron, Royal Flying Corps (RFC), and would retain this designation until it reverted to its original title on 19 January 1918.

The squadron arrived in France on 18 December 1917 and established itself at Bruay. It was assigned to the 10th Wing of the Royal Flying Corps, and operated in support of the British 1st Army, undertaking offensive patrols and escorting reconnaissance machines. The unit's first patrol over German lines took place on 9 January 1918, and its first air combat action occurred on 13 January 1918.

Towards the end of February 1918 the squadron was increased from 18 to 24 machines, considerably enhancing its capacity for offensive operations. March 1918 saw an increase in the squadron's ground attacks and offensive patrols, including a notable engagement with elements of Manfred von Richthofen's "Flying Circus" on 21 March, during which five enemy machines were downed in an attack led by Captain Arthur Henry Cobby.

During the German spring offensive, the squadron was heavily involved in strafing and bombing operations in support of the retreating Allied ground forces. Threatened by the German advance the Squadron moved from Bruay to Clairmarais North on 28 April 1918 and joined 11th Wing, part of the British 2nd Army.

Due to repeated enemy bombing attacks on the Clairmarais North airfield, the Squadron moved to Reclinghem on 30 June, where it shared the aerodrome with 2 Squadron AFC. Both squadrons formed part of 80th Wing under the British 5th Army. In July, the squadron was heavily involved in offensive patrols and also provided escorts for bombing and reconnaissance missions. 4 Squadron maintained a high operational tempo throughout the great Allied offensive launched in early August 1918.

At the end September 1918, 4 Squadron moved to Serny and in early October was re-equipped with Sopwith Snipe fighters; it was only the second unit in France to be equipped with these advanced machines. The squadron was relocated several times during the last month of the war, and following the Armistice was assigned to the British Army of Occupation. It moved to Bickendorf, near Cologne on 17 December 1918. In March 1919 the unit returned to the United Kingdom and on 6 May embarked on RMS Kaisar-i-Hind for the return voyage to Australia. 4 Squadron arrived in Melbourne 16 June 1919 and was subsequently disbanded.