 The first, A8-126, received these modifications in the United States between October 1979 and April 1979; the other three were converted in Australia between July and September 1980.The RAAF purchased four ex-United States Air Force (USAF) F-111As in 1981 as attrition replacements.These aircraft were delivered to the service in 1982 and were subsequently converted to F-111C standard.