No. 27 Squadron of the Royal Air Force operates the Boeing Chinook from RAF Odiham. History First World War 27 Squadron of the Royal Flying Corps formed at Hounslow Heath Aerodrome on , being split off from 24 Squadron. Initially using aircraft borrowed from 24 Squadron, 27 Squadron moved to Swingate Down outside Dover in late November 1915, and in early February 1916, received its initial operating equipment, the Martinsyde Elephant fighter aircraft, hence the use of an elephant for the squadron badge. It transferred to France on 1 March 1916, serving as part of 9th Wing RFC. Initially the squadron was tasked with using its aircraft as escort fighters, but by the time the Battle of the Somme began, it was clear that the Elephant was unsuitable as a fighter. At the Somme, the squadron was initially tasked with mounting standing fighter patrols to protect British bombers and reconnaissance aircraft and with bomber-reconnaissance duties, taking advantage of the Martinsyde's good range and load carrying capacity, carrying out its first bombing mission on 1 July 1916. It was ordered to concentrate on bombing duties on 9 July. The squadron continued to operate its Martinsydes into 1917, taking part in the Battle of Arras in April–May, the Battle of Messines in June, where the squadron attacked German airfields, and the Battle of Passchendaele (also known as the Third Battle of Ypres), where the squadron attacked railway targets and airfields, from July that year. It re-equipped with Airco DH.4s, which carried twice the bombload of the Martinsyde at greater speed and height, while carrying a gunner to defend against enemy fighters, from between September and December 1917, but was still equipped with a mixture of Martinsydes and DH.4s when it flew in support of the British offensive at Cambrai. In March 1918, the squadron moved to Villers-Bretonneux east of Amiens as part of a concentration of the RFCs resources against the likely route of a suspected German offensive. The morning of 21 March brought the start of Operation Michael, the opening part of the German spring offensive. At first the squadron was deployed against railway junctions, to slow the movement of German reinforcements. On 24 March, the squadron was forced to evacuate from Villers-Bretonneux, threatened by the German advance, to Beauvois-en-Cambrésis. On 25 March, as the Germans threatened to breakthrough near Bapaume, all available squadrons, including 27 Squadron, were ordered to carry