 A consortium of Israel Aerospace Industries and Hawker de Havilland converted four of No. 33 Squadron 's six serviceable aircraft to in @-@ flight refuelling tankers between December 1988 and May 1992 . Their probe @-@ and @-@ drogue configuration allowed them to refuel the RAAF 's F / A @-@ 18 Hornets and the Royal New Zealand Air Force 's Douglas A @-@ 4K Skyhawks , but not the RAAF 's General Dynamics F @-@ 111 bombers , which required a boom system ; the other two 707s continued to be used purely for long @-@ range transport . The RAAF had argued for an air @-@ to @-@ air refuelling capability for both the F / A @-@ 18s and the F @-@ 111s , but the Australian government refused to fund the latter , considering the F @-@ 111 's existing range sufficient for deterrent purposes . Observers such as journalist Frank Cranston speculated that aside from any cost issues , the government was concerned that extending the bombers ' range would signal to the region that Australia was adopting a more aggressive defence posture . 
