RAF Mona is a Royal Air Force station near Bodffordd on the island of Anglesey, Wales. It is primarily used as a relief landing ground for RAF Valley. RAF Mona is also the home of Mona Flying Club who operate some evenings and most weekends. History First World War This location was first used for aviation during the First World War when the Royal Naval Air Service opened an airship base here named Royal Naval Air Station (RNAS) Anglesey (also known as RNAS Bodffordd, RNAS Gwalchmai and RNAS Llangefni). RNAS Anglesey was commissioned on 26 September 1915, when it was operated by 14 Group RNAS, operating SS18, an SS class airship, which was later joined by airships SS22, SS24 and SS25. The station had in a large airship hangar, long, workshops, hydrogen gas production sheds and accommodation huts. The airships, which could drop bombs, escorted ships and patrolled for enemy submarines in the central section of the Irish Sea between Bardsey Island, Dublin, the Isle of Man and Morecambe Bay. This area includes the approaches to the Port of Liverpool, then one of the busiest ports in the world. In June 1917 three SSP class airships, SSP1, SSP5 and SSP6, replaced two of the original SS class airships, the other two old airships continued in use. The airships were later replaced by eight SSZ class airships, which had greater speed, endurance and bomb load. The airships communicated by radio with a relay station at Llaneilian on the north coast of Anglesey, whose operators contacted the airship station by telephone. In November 1917 an unsuccessful attempt was made to base Airco DH.4 light bomber biplanes at RNAS Anglesey. From August to November 1918, eight Airco DH.6 biplanes of No. 255 Squadron RAF were based at RNAS Anglesey, but the poorly-drained land caused difficulty, and the aircraft were transferred to the newly opened Bangor Aerodrome on the mainland. In July 1918 a mooring-out site was established in the grounds of Malahide Castle, north of Dublin. There were plans to base airships at Malahide from 1919, but the plans were abandoned at the end of the war. Experimental work conducted at RNAS Anglesey during the First World War included the use of hydrophones suspended under airships to detect submarines, the use of phosphorus to create smoke screens at sea, and the use of hydrogen from the airship envelope to fuel the engine. At