No. 3 Fighter Sector (3FS) was a Royal Australian Air Force (RAAF) unit during World War Two. No. 3FS was responsible for fighter aircraft control and coordination for the Townsville region. 3FS would collect all of the intelligence information from the various D/F stations and VAOC posts, decide on the what needed to be done and then tell the fighter or bomber squadrons to respond. 3FS was in telephone and radio contact with all of the anti-aircraft, searchlight, RDF and HF/DF stations in the Townsville area.