special-rules zone

special-rules zone (SRZ)

An area of protected airspace surrounding an airfield and extending from the surface upward to a specific level that affords safety to air traffic movements in the vicinity of airfields whose traffic level does not warrant the establishment of a control zone. Also, a special-rules area, or an SRA, extending vertically and horizontally from a level above the surface but not necessarily terminating at the same upper level as the SRZ.