out low level attacks against the German troops. The squadron continued to fly a mixture of low level attack against troop concentrations and high level attacks over the next few days, and on 29 March was forced to move airfields again, this time to Ruisseauville. On 1 April 1918, the RFC merged with the Royal Naval Air Service to form the Royal Air Force, but this had little effect on the squadrons at the front, with 27 Squadron continuing to operate against the German offensive. On 9 April, the Germans launched the second stage of its offensive, an attack near the River Lys at the junction between the British First and Second Armies. 27 Squadron was again deployed against the offensive attacking railway targets from 12 April. It started to receive DH.9 bombers in July 1918, but as these proved to be inferior to the DH.4, managed to keep some of its DH.4s until the end of the war. The squadron was disbanded on 22 January 1920. Inter-war period On 1 April 1920, No. 27 was reformed by re-numbering No. 99 Squadron RAF then in India, flying Airco DH.9A light bombers from Risalpur over the North-West Frontier. Operations included Pink's War, an aerial bombardment campaign against militant Mahsud tribesmen in South Waziristan in March and April 1925, the first colonial policing action carried out solely by the RAF, without the participation of the British Army. The squadron's DH.9As were eventually replaced by Westland Wapitis in 1928, when the squadron moved to Kohat. In December 1928, Flying Officer Tusk and Leading Aircraftman Donaldson (both of 27 Squadron), flew the first mission of the Kabul Airlift. Strictly a reconnaissance flight to ascertain the situation of the British Legation in Kabul during a civil war, they were shot at by local tribesmen and forced to land at a nearby airstrip. After this they managed to dash across no-man's land and arrived at the legation to set up communications with their home base of Risalpur. War in the East The outbreak of the Second World War in Europe in September 1939 saw part of the squadron deployed on coastal anti-submarine and anti-shipping patrols from Madras, before on 1 October 1939, the squadron became a flying training school training pilots for the Indian Air Force, operating de Havilland Tiger Moth and Hawker Hart biplanes as well as Wapitis, and based at Risalpur. Many of the