 Prior to World War II , the Royal Australian Air Force was small enough for all its elements to be directly controlled by RAAF Headquarters in Melbourne . When war broke out , the RAAF began to decentralise its command structure , commensurate with expected increases in manpower and units . Between March 1940 and May 1941 , Australia and Papua were divided into four geographically based command @-@ and @-@ control zones : Central Area , Southern Area , Western Area , and Northern Area . The roles of the area commands were air defence , protection of adjacent sea lanes , and aerial reconnaissance . Each was led by an Air Officer Commanding ( AOC ) who controlled the administration and operations of all air bases and units within his boundary . 
