F-111 Avionics Upgrade Approved

With the RFT being issued prior to Christmas, it was hoped a winning contender would be announced before the end of 1989 which would then allow the first aircraft to be in service around 1992/93. It is planned that between 3 and 4 aircraft would be upgraded annually while the first aircraft to be converted would be the colourfully painted test aircraft presently in use with Edinburgh’s Aircraft Research & Development Unit (ARDU).

This of course is not the first significant update that 82 Strike Wing’s F-111 force have had. Dating back nearly a decade the RMF decided to equip our aircraft with the very potent Pave Tack precision strike targeting system, a $167m decision that led to the first of type entering RAAF service in the mid eighties.

Australia acquired 24 F-111C aircraft during the early sixties as a Canberra bomber replacement during the heady days of Confrontation with Sukarno’s Indonesia. Problems initially led to the aircraft being technically mothballed in the US from 1968 through till 1973 when they finally entered RMF service. The primary problem at that time was with the complex wing folding mechanism, a situation that was fully rectified prior to entry to RAAF service. Australia later acquired 4 additional ex-USAF F-111A aircraft which were then converted to C standards.

Ironically the RAAF had all along required a long-range, all weather, reconnaissance capability and was looking to use the F-111 in this role. The most cost effective solution would have been to have acquired 4 F-111A aircraft from US reserves of the time and convert them without bringing them up to C standards. However, funds were constantly denied this logical acquisition and so the RAAF was eventually forced to modify 4 existing C aircraft to RF-111 C standards. With attrition came a requirement to obtain rare aircraft and so finally DoD was forced to purchase, at a much higher unit price, the 4 F-111As that it rejected several years earlier.

Today the RMF operates 18 F-111Cs in the strike role and 4 RF-111C in the recce role. While A series aircraft are presently scarce, the RAAF still hopes that some additional A models might be procurable during the early nineties to bring both squadrons back up to their full complement. No82 Wing comprises No1 and No6 squadrons, 1 being the primary strike squadron while 6 is used as the hybrid strike and training/ conversion squadron and also is home to tM recce birds.

Pave Tack has given the RAAF an entirely new strike capability far superior to that of any other resident air arm in South East Asia. The F-111C is indeed a difficult aircraft to replace. Fully loaded it has a conservative tactical radius, without tanking, of over 1,000nm. Nothing can come near that and still approach the target at minimum height using its Terrain FollowingRadar at 500kts plus. The use of minimal weight Precision Guided Munitions (PGM), tanker support and an advanced nav/attack system allows the aircraft to operate over ranges restricted only by crew fatigue, as was ably demonstrated by the 1986 USAF F-111 raid on Libya.

The Pave Tack system is housed in the aircraft’s bomb bay and is lowered on approach to the target area. Target acquisition can be accomplished using any one of several manual or computer search modes. The field of view and scene magnification can be selected to enhance target recognition. The target, once located by the Weapon Systems Operator(still quaintly referred to as a Navigator in RAAF parlance), can be locked up and designated everi if the aircraft is performing severe evasive manoeuvres. Once target tracking is established, the laser can be fired continuously to determine exact target range until weapons release. If laser guided weapons are being deployed, the laser is again continuously fired after weapons release, while maintaining target tracking, until weapon impact. During target egress the target area is still tracked for damage assessment. Thus the entire mission can be performed at high speeds at minimum altitudes during adverse weather conditions at any time day or night.

With the GBU-15 the swivelling seeker head slaves on to the image of the target while the navigator locks up the target visually in preparation for launch of the TV guided 2,000Ib GBU-15 glide bomb. A 4G pull up is then initiated and the bomb is tossed into a trajectory that will maximise its range profile thereby keeping the launch aircraft well away from the potent area defence systems likely to be encountered around any priority one target. Once stabilised in flight the operator can then guide the bomb directly onto its target with unerring accuracy. By the time the bomb has impacted its target the 111 is well away, in the weeds and heading for home at high speed. The radar image the aircraft displays on its initial pull up would be, in most cases, the first evidence of an attack.

And the results of such an attack is indeed impressive. According to the RAAF, the Circular Error Probable(CEP, a measure of the bombing accuracy of different air to ground weapons) of using standard unguided bombs is 131ft. Using Pave Tack and with GBU-15 the CEP comes down to a devastatingly accurate 3ft, with the laser guided Paveway series 2,000Ib GBU-10 and