Avro 521

The Avro 521 was a British two-seat fighter first flown in late 1915 and based on the Avro 504, of which only a prototype was built. It was powered by a 110 hp Clerget engine, with provision for a .303 in Lewis gun in the rear cockpit. The prototype underwent trials with the Royal Flying Corps in early 1916 and 25 aircraft were ordered, but the contract was cancelled and there is no evidence that any other Avro 521 was built. The prototype crashed at the Central Flying School at Upavon on 21 September 1916, killing its pilot, Lieutenant W.H.S. Garnett.