The acquisition of the RAAF's fifteen F-111G aircraft was without doubt one of the best value for money defence purchases of the last decade. These capable aircraft are aerodynamically superior to the RAAF's F/RF-111C fleet, with better climb performance, range and a more robust inlet design.

    While the purchase of these aircraft was by all means a sensible decision, budgetary constraints set by the former government meant that no additional expenditure was authorised to provide type specific support. It was expected that resources required to support the aircraft would be found elsewhere in the existing defence budget, including Air Force programs. The initial funds for purchasing the aircraft amounted to A$70M, and an additional A$74M was reallocated in the existing budget to provide logistical support. Per airframe this amounts to just under A$10M, which compares very favourably with the cca A$70M one would pay for a new fighter bomber, excluding logistical support costs.

    Reacting to these circumstances, the RAAF quietly conducted the customary study on the logistical supportability of the aircraft, while concurrently evaluating the type operationally to decide how best to integrate the aircraft into service with 82 Wing. An unusual aspect of the former government's directive to the ADF was that the aircraft was not to be subjected to a weapon system upgrade to improve supportability, as is being done to the F/RF-111C under the AUP program.

    The F-111G project was initially managed by the DoD's Department of the Secretary of Acquisition and Logistics, who retain responsibility for managing the DFCS upgrade, G-02 software upgrade, G-WSSF and provision of ATE (see below). In service logistical management responsibility was transferred to the RAAF's 501 Wing in late 1995.

    A number of upgrades for the F-111G are currently in the pipeline, scheduled for implementation, and a number of upgrades are under serious consideration. The intention is to provide a degree of commonality with the post AUP F/RF-111C aircraft to minimise support costs, and maximise operational availability.

    All F-111G aircraft will be fitted with the Digital Flight Control System (DFCS) used in the F/RF-111C AUP aircraft (see AA Aug/Sept 95). At this time, component kits have been acquired for all fifteen aircraft. The six aircraft currently on the flightline will be refitted first with a target IOC for the DFCS upgrade by 1998. Remaining aircraft will be refitted during scheduled deep maintenance work in the latter years of the decade.

    Concurrently, the RAAF is proceeding toward a domestic software support capability for the aircraft's mission computers. The RAAF intend to field the G.02 software (OFP) upgrade by the end of 1997, which will see the RAAF acquiring the source code for the computers. Because of the aircraft's SAC origins, this source code had to be purged of all modules which related to the aircraft's former SIOP mission and weapon types.

    The acquisition of source code will be paralleled by the provision of the G-WSSF software support and development environment. At this time it is unclear how much effort would be required to adapt the existing F/RF-111C AUP software maintenance environment to support the G-model. Because the G-model uses the AYK-18 mission computer, and has a number of avionic differences from the AUP system (no Pave Tack, different INS, no GPS, Doppler Nav), the software developed for the AUP cannot be used without a large number of modifications, and qualification testing. As well numerous hardware and software changes would be required to the AUP WSSF. The issue of software support is complicated by the fact that the AUP upgrade employs newer and more powerful AP-102A computers, which although using the same 1750A architecture binary code as the AYK-18, do differ sufficiently to make the software non-portable across the machines.



    The USAF had originally sought a progressive computer upgrade for the F-111A/E/G and upon the retirement of the F-111G, the F-111E/F. With the impending retirement of the USAF F-111 fleet, this upgrade was cancelled. The upgrade would have involved shrinking the two mission computer black boxes down to a pair of boards, shrinking an avionic interface box and stores management box down to a pair of boards and repackaging the whole set in to an existing black box chassis. This upgrade had progressed to the point of flight testing on an FB-111A airframe, using bare bones software, but was cancelled in early 1995 due the budgetary decision to retire the whole fleet. This decision also led the USAF to cancel a planned upgrade of the F-111F Pave Tack with a new Texas Instruments Focal Plane Array thermal imager, which would have significantly improved the reliability and picture quality of the Pave Tack.

    The RAAF is therefore faced with two options in this area, should they wish to maintain a substantially unique F-111G avionic suite. The first is to acquire boneyard spare (obsoleted) AYK-18s to provide for hardware support, and maintain highly specific software for the F-111G, with dedicated programmers and development systems. The second option, involving higher short term expenditure, but lower long term costs, is to refit the aircraft with the better AP-102A computer, common to the AUP aircraft. The latter alternative yields the benefit of shared computer hardware logistics between the G and C aircraft, and the ability to use a lot of common source code. The common components of source code would then be compiled with options either for the C or the G model, to accommodate avionic and aerodynamic differences between the aircraft. The RAAF is yet to decide which strategy to follow in this area, although it is fair to say that a refit with AP-102s is a technically and logistically much cleaner solution. It is intended that the G-WSSF, in whatever form it takes, be operational by 1999.