sentences:  No.55 Squadron was formed at Castle Bromwich on 27 April 1916.It initially operated as a training unit, flying a mixture of types, including the Avro 504, Royal Aircraft Factory B.E.2 and the Armstrong Whitworth F.K.8, but in January 1917 it changed its role to a day-bomber squadron and re-equipped with the Airco DH.4, being the first squadron to receive the new light bomber.