Aircraft of the ADF-A8 General Dynamics F-111

Conceived in the early sixties as the TFX (Tactical Fighter Experimental), the F-111 was to provide a strike capability to the USAir Force Tactical Air Command (TAC) with the F-111A and later models, and to the Strategic Air Command (SAC) with the FB-111 series. Additionally, an air superiority capability for the US Navy was to be provided by the F-111B variant which was later discontinued in favour of the F-14.

For the Canberra replacement in 1963, the Government took the unusual step of ordering 24 TFX aircraft while still in the design phase. This led to much criticism over subsequent years as development problems and escalating costs plagued the F-111 production program. Perhaps this could have been expected of such a radical design utilising variable geometry (sweeping wings), and terrain following radar – TFR- which allowed automatic blind low level flight.

The first prototype F-111, numbered 63-9766, flew on December 21 1964, and was followed by 16 preproduction deve opment aircraft, and then 142 F-111As for TAC and 76FB-111As for SAC. The 24 RAAF aircraft, designated as F-111Cs and serialled A8-125 to A8-148 (which had been allocated USAF serials 67-125 to 67-148), were the F-111A version, but with the longer wingspan and heavier undercarriage of the FB-111A. The Royal Air Force ordered 50 similar models, the F-111K, but this order was cancelled.

Later USAF models included 96 F-111D, 94 F-111E, and 106 F-111F, the ultimate F-111 in performance and advanced avionic systems. Subsequently, 42 F-111As were modified by Grumman to EF-111A Raven electronic warfare jamming aircraft, but the programme to modify SAC FB-111s to F-111G standard for TAC was subsequently curtailed after 36 had been modified to the tactical bomber standard. A total of over 560 F-111s were finally built.

The first F-111C was handed over to the RAAF on September 4, 1968, but problems with the wing carry-through box (the advanced wing sweep mechanism) delayed delivery to Australia. After further development and testing, and after much negotiation regarding aircraft fatigue life, the aircraft re-mained stored at General Dynamics until final acceptance in 1973. For part of this period, 24 F-4E Phantoms were leased to provide an interim attack capability, until finally aircrew and maintenance personnel deployed to the US to convert and ferry the F-111s back to Australia. The first of four delivery flights, led by GpCpt J W Newham (later CAS) and WgCdr (later AirCdre) TC Owen in A8-125, finally arrived at Amberley on June 1 1973. The last of the delivery flights arrived on December 4.

The F-111 equips Nos 1 and 6 Squadrons of 82 Wing in the Strike Reconnaissance Group (SRG) for maritime and land strike. Four have been modified as RF-111C reconnaissance aircraft, used by 6 Sqn, which is also tasked with crew conversion to the F-111. In 1981, four USAF F-111As were purchased to make good attrition. These were serialled 67-0109, -0112, -0113 and -0114, and on delivery in 1982 became A8-109 to A8-114. They were subsequently modified to full F-111C stan- dard.

The F-111 is a remarkable aircraft. With its long range and weapons carrying capability, its avionics fit which allows all-weather strike, and by virtue of the TFR allowing low level penetration to the target, the F-111 is unique, and to date no viable replacement has emerged.

To add to its attack capability, the RAAF has modified the F-111C to carry the Pave Tack forward looking infrared (FLIR) and laser target designation pod. The Pave Tack FLIR pas- sively enhances target identification in weather and at night, and the laser designator enables homing oflaserguided bombs, the effects of which were graphically demonstrated by allied forces during the Gulf War.

The F-111 is still the world’s leading long range strike aircraft, but to improve both its capability and maintainability the RAAF has embarked on the Avionic Update Program (AUP) with advanced systems to keep the F-111 in the front line through to the year 2010. Aircraft A8-132 is now in the USA as the AUP prototype, and subsequent aircraft will be modified in Australia. AUP aircraft will enter service in 1994 and the upgrade is due to be completed by 1997. To ensure 22 aircraft complete the AUP, an additional two airframes are held in- reserve in the US for the RAAF. These are 67-0095 and 67-0106. In October 1992 the Minister for Defence announced the proposed acquisition of up to 18 surplus USAF F-111s to extend the type’s service life. Ultimately 15 F-111G models were selected as the most suitable for introduction to RAAF service, and this acquisition is now due for Government approval. These aircraft are serialled in the batches 68-0259 to 68-0291, and 69-6506 to 69-6514. If this programme does go ahead, it is anticipated these aircraft will be amalgamated with the F-111C fleet at SRG as an in-use reserve, without the formation of a further F-111 squadron.

The F-111G does share commonality with the F-111C with the longer wingspan and heavy undercarriage. The G also shares some of the avionics fit that will be fitted during the F-111CAUP, notably the same TFR and attack radar, and the same multi function displays for the aircrew. However, other aspects of the F-111G are different. The avionics will not be fully compatible with the AUP, and also the G is powered by Pratt & Whitney P-107 turbofans. These cannot be standardised with the F-111C’s P-103s due to the different intake and fuselage shape. The extent of these differences is not considered to be insurmountable.

Assuming Government endorsement for the F-111G project (which was imminent at presstime), deliveries could commence as early as July this year. The USAF plan to retire the last F-111G this October, and the RAAF aircraft would be ferried from California by Australian crews.

F-111C aircraft were produced in 1968 and remain unsurpassed in capability. If still in service in 2010, these aircraft will be over 40 years old. For an attack warplane, this is unprecedented and is a truly remarkable feat.