On October 24, 1963, the government of Australia agreed to purchase 24 F-111As as a replacement for the English Electric Canberra.
Initially, the Australian F-111 was to be virtually identical to the USAF F-111A, but by April of 1966 the configuration had changed to that of a hybrid between the F-111A and the FB-111A, to be designated F-111C. The F-111C was equipped with eight underwing pylons mounted on an F-111B-type larger span wing (span of 70 feet when fully extended). It was equipped with with an FB-111 type of reinforced undercarriage. The twenty-four F-111Cs were given the USAF serial numbers 67-125/148. Their RAAF serials were A8-125/148.
The first F-111C was officially handed over on September 6, 1968. However, the problems with the F-111A's wing carry-through box slipped delivery of the remaining 23 F-111Cs to late 1969. To make matters worse, the whole F-111 fleet had to be grounded pending verification of their overall structural integrity. The remaining F-111Cs awaiting delivery to Australia were stored at Fort Worth until the structural integrity of the F-111 could be confirmed.
In April of 1970, a joint agreement between General Dynamics and Australia deferred the RAAF's acceptance of the F-111C pending the verification of their structural integrity. The RAAF was to lease F-4E Phantoms as an interim aircraft while new wing carry-through boxes were installed on all F-111Cs before being delivered to the RAAF. This refurbishment program began on April 1, 1972.
In 1973 the F-111C was finally ready for delivery to the RAAF. The first F-111C was formally accepted on March 15, 1973. Australian crews came to the USA, and, one-by-one, these crews flew their new mounts from Fort Worth to McClellan AFB. Once at McClellan, the Australian crews flew several training missions before leaving for Australia. The first F-111C reached Australia on June 1, 1973, followed shortly thereafter by the rest of the fleet. The last F-111C was delivered to Australia on December 4, 1973.
The F-111Cs were operated by Nos. 1 and 6 Squadrons based at Amberley, Queensland. The F-111Cs replaced the RAAF's fleet of English Electric Canberra bombers that has been in use since the 1950s.
The F-111C carries the APQ-113 forward-looking attack radar, which is used for navigation, for air-to-ground ranging and for weapons delivery. In theory, this radar can also be used in the air-to-air mode in conjunction with the internal 20-mm cannon or Sidewinder missiles carried underwing, although this is not the primary mission of the F-111C.
A8-133 was lost in 1977 when it struck three pelicans. This demonstrated the vulnerability of the aircraft to birdstrikes during low-altitude high-speed operations, and laminated ADBRIT windshields were fitted to the entire fleet.
The RAAF had originally also ordered six reconnaissance versions known as the RF-111C. However, the USAF cancelled the entire RF-111A/RF-111D program in 1968, leaving the RAAF without the reconnaissance version it had ordered. In order to meet this need, a contract was signed with General Dynamics on December 31, 1974 for four of the original F-111Cs to be converted to the RF-111C reconnaissance role and delivered to Australia. The first of these (A8-126) was flown on April 17, 1979 and was redelivered in August of 1979. The remaining three aircraft were converted at Amberley using General Dynamics-supplied kits during 1980. The reconnaissance suite is mounted on a pack that fits inside the weapons bay. The reconnaissance "kit" comprises two CAI KS-87C split vertical framing cameras, a Fairchild KA-56E low-altitude and KA-93A4 high altitude panoramic camera, and a Honeywell AN/AAD-5 Infrared Linescanner. There is a TV viewfinder which assists with line up for the photo run. The aircraft is also equipped to allow photography of the AN/APQ-113 attack radar display. The RF-111C retains full conventional attack capability. The four RF-111Cs bear the serials A8-126, -134, -143, and -146, and they serve with No. 6 Squadron.
The F-111C can also carry the AN/AVQ-16 Pave Tack laser designation pod, fitted inside the weapons bay. A rotating cradle allows the pod to be carried entirely internally, rotating down only when actually in use. The first Pave Tack-capable F-111C (A8-138) was modified at Fort Worth in December 1983, ith the rest of the surviving fleet being modified at Amberley beginning in 1985.
The F-111C can carry the AGM-084A Harpoon anti-ship missile. The AGM-88 HARM anti-radiation missile was also tested on the F-111C, but has not been procured.
In 1982, four F-111As surplus to USAF requirements were transferred to the RAAF as attrition replacements. Before being delivered, they were modified to F-111C standards with longer span wings and strengthened undercarriages. Their RAAF serial numbers were A8-109, -112, -113, and -114.
Under Project AIR 5225, the RAAF planned to carry out an Avionics Upgrade Program (AUP) of the F-111C's largely analog avionics suite to fully digital standards. In August of 1990, Rockwell was given a contract to update 18 F-111Cs and four RF-111Cs at its Palmdale plant. Fully 90 percent of the electronics in the F-111C were replaced by more capable units. The upgraded aircraft has an improved digital Stores Management System which provides compatibility with a wider ranging group of weapons. The avionics is based on the MIL_STD-1553B digital databus. There is a new digital computer complex with two IBM AP-102 mission computers. The computer has a pre-programmable data cartridge which allows a fully-planned mission to be loaded into the aircraft before flight. There is a new navigation system built up around the Honeywell 423 (AN/ASN-41) ring laser gyro, augmented by a Rockwell-Collins GPS. The analog flight control system is replaced by a digital fly-by-wire system. The terrain-following radar is replaced by a Texas Instruments AN/APQ-171 system, and the beam mapping attack radar is upgraded to AN/APQ-169 standards. The first upgraded F-111C was A8-132. The last AUP-modified F-111C was returned to the RAAF at Amberley in November 1999. This upgrade should keep the RAAF F-111Cs flying until the year 2020.
In October 1992 it was announced that Australia planned to buy 18 surplus F-111Gs from the USAF to augment the 22 surviving F-111Cs in the RAAF fleet. The price was described as "bargain basement", about $AUD60-80M; plus $AUD10-15M per plane for upgrades. ($AUD 1 =~ $USD 0.72). Delivery began in 1994. One aircraft (68-272) was taken from AMARC storage, but the remainder were taken directly from Cannon AFB when the 27th Fighter Wing exchanged them for F-111Es.
There were some differences between the F-111Gs and the existing F-111Cs. The F-111G had a longer range and better ECM capabilities than the original F-111C. The F-111Gs had the more powerful TF30-P-107 turbofan rather than the P-103 of the F-111C and had different (Triple Plow II) intakes. The F-111G was not compatible with the Pave Tack laser designation pod and had an AYK-18 mission computer. Before their retirement, the F-111Gs were fitted with the ASN-41 ring laser gyro inertial navigation system and were fitted with an APN-218 Doppler. After delivery to Australia, these planes were fitted with the same digital flight control system as was fitted to the F-111Cs under AUP. There was some thought given to having the F-111Gs also go through the AUP upgrade
Initially, it was planned to use the F-111Gs primarily as spares, but also perhaps as a possible attrition reserve. However, by the time that the first two F-111Gs had arrived at Amberley on September 28, 1992, it had been decided that some of them would be used as an "in-use" reserve, and No 6 Squadron was given a flight of 6 F-111Gs.
Since 1994, the F-111Cs and RF-111Cs have been re-engined with TF30-P-109RA 20,840 lb.s.t. turbofans taken from retired F-111Ds and EF-111As.
There are plans to fit the F-111Cs with indigenous ALR-2002 radar warning receivers replacing the existing ALR-62. There are also plans to fit a radar jammer to replace the Sanders ALQ-91 and ALQ-137 defensive electronic countermeasures package. The ALR-2002 began flight trials during late 1999. AN/ALE-40 chaff/flare dispensers are replacing the AN/ALE-20. A request has been issued for a podded electronic countermeasures jammer, the AN/ALQ-131 and AN/ALQ-184 being possible contenders.
In 1998, the RAAF announced that it planned to keep its F-111 fleet flying until at least 2020. In order to support this plan, it was decided that the remaining F-111Gs would be reactivated and that ten redundant ex-USAF airframes would be acquired for cannibalization to form an attrition reserve. The RAAF will have the option to purchace the attrition reserve airframes directly at a later time should the need arise.
A8-125/A8-148 USAAF serials 67-125/148 A8-106 ex USAF F-111A 67-106 held in reserve in USA for RAAF spares A8-109 Ex USAF F-111A 67-109 purchased by RAAF in 1982 and upgraded to F-111C A8-112 Ex USAF F-111A 67-112 purchased by RAAF in 1982 and upgraded to F-111C A8-113 Ex USAF F-111A 67-113 purchased by RAAF in 1982 and upgraded to F-111C A8-114 Ex USAF F-111A 67-114 purchased by RAAF in 1982 and upgraded to F-111C A8-259 Ex USAF F-111G 68-259 A8-264 Ex USAF F-111G 68-264 A8-265 Ex USAF F-111G 68-265 A8-270 EX USAF F-111G 68-270 A8-271 ex USAF F-111G 68-271 A8-272 ex USAF F-111G 68-272 A8-274 ex USAF F-111G 68-274 A8-277 ex USAF F-111G 68-277 A8-278 ex USAF F-111G 68-278 A8-281 ex USAF F-111G 68-281 A8-282 ex USAF F-111G 68-282 A8-291 ex USAF F-111G 68-291