The Garda Air Support Unit (or GASU) is a unit of the Garda Síochána which was formed in 1997. The GASU is part of the Operational Support Unit which provides specialist support to Gardaí nationwide. The Operational Support Unit also includes the Water Support, Dog Support and Mounted Support Units.The GASU's aircraft are maintained and flown by the Irish Air Corps, and based at Casement Aerodrome near Dublin.