Technology Explained — Tankers as Force Multipliers

The payoff in the use ofAAR was evident and by the early sixties both TacticalAir Command (TAC) and the US Navy moved to equip their tactical aircraft with refuelling hardware. TAC retained the now USAF standard boom receptacles, while the USN

adopted the cheaper and smaller probe/drogue technique. The probe/drogue technique involves the tanker trailing a hose with a drogue equipped receptacle, with receiver aircraft manoeuvring their probes into the drogue for a hookup. The advantage of this technique lay in the relatively compact and light hardware to be fitted to thetanker, a prerequisite for the USN who employed carrier based tactical airframes for the role, ie the KA-3 and KA-6D Skywarrior. The limitation of the probe/drogue hardware was in its restricted fuel transfer rate of less than 1,000lb/min although this was hardly a problem with the relatively small single or twin engined tactical jets.

By the late sixties the US had clearly become the Free World’s largest user of AAR, with the UK trailing second. The RAF employed the probe/drogue technique, refitting obsoleteValiant and later Victor bombers for the role. Tactical aircraft were refuelled from wingtip pods, while a much heavier fuselage hose/drogue system was fitted to refuel bombers and transports at much higher transfer rates.

The Vietnam conflict clearly illustrated the benefits in the use of AAR and it is without doubt that SAC and USN tankers played one of the most important yet least publicised roles in the war. The massive air campaigns flown against the North relied heavily upon AAR support and could not have been successful without the tankers. This view was further reinforced by the demands of the massive MAC airlift to Israel during the 1973 Yorn Kippur war.

By the late seventies, operational technique had matured on both sides of the Atlantic and AAR had become firmly embedded in both tactical and strategic air operations. The demand for AAR capacity had grown and a new generation of tankers was sought. In the US, SAC looked toward a strategic heavyweight tanker/ transport to support SAC, MAC and long range deployments by TAC who had by then become committed to the Rapid Deployment Force. A contest between the Boeing 7 4 7 and DC-10-30CF was won by the McDonnell Douglas aircraft,with the USAF eventually acquiring 60 of these capable aircraft. With an MTOW of 590,000lb and fuel capacity of 345,000lb the KC-10 has truly global capability, with its considerable freight capacity it has vastly simplified TAC deployments as most of the support personnel and equipment for the fighter aircraft travel aboard the tankers.

The UK’s tanker force had a much rougher ride. The late seventies saw nine VC10 airframes earmarked for conversion to dual role tanker/transports to support RAF air defence operations in the North Atlantic and North Sea. These aircraft were not operational though in 1982, and thus only two squadrons of Victors formed the backbone of the tanker force when the Argentines invaded the Falkland Islands. Committed to regaining the territory, the UK suddenly found itself with a drastic shortage of tankers given the incredible demands of the campaign. Operations in the South Atlantic saw Nimrods quickly fitted with probes, subsequently C-130s fitted with probes and some C-130s fitted with fuselage hose/drogue hardware in makeshift installations to refuel other C-130s. The RAF tanker force acquitted itself admirably by the end of the campaign, with many complex operations often involving multiple tanker to tanker refuellings to provide transports and Vulcan bombers with the fuel needed to operate over the remote South Atlantic. Success came at a price though, with many Victor aircraft quickly using up much of their remaining airframe life.

The Victors are now due for early retirement, their role to be taken over by mixed force of 13 VC10K. 2 and VC10K. 3 aircraft which are due for conversion over the next two years. In addition to the VC1Os, the RAF acquired six former BA Lockheed L1011-500 Tristars, which have been converted to tanker/transport configuration. Three former PanAm Tristars are also due for conversion.

One of the major reasons for the RAF’s large commitment to AAR is the air defence situation in the North Atlantic, which has seen the Russians build up a large force of Backfire bombers with supporting Flanker long range fighters. Theseaircraft would strike at targets in the UK and interdict shipping and thus the RAF is in the process of expanding its long range air defence capability. This situation has prompted the US Navy, which has a commitment to a forward deployed maritime posture, to investigate land based tankers as a supplement to carrier based tankers. SAC, however, jealously guard their territory and are now in the process of flight testing Mk. 32B pods on a KC-10 and are looking toward retrofitting pods on to a number of KC-135 airframes. The KC-135 force is becoming expensive to run with J57 turbojets and SAC are progressively refitting these aircraft with CFM56 fans and, in some instances, TF33 (JT3D) fans reclaimed from older civil 707 aircraft bought up second hand and held in storage.

While the US and the UK clearly lead the Free World in terms of size and capability of AAR forces, other nations have followed the lead. Spain, Morocco, Canada (2), Brazil (4), Israel (5) and Saudi Arabia (6) have all acquired 707 derivative tankers, with Italy, West Germany and Japan currently considering their options. Of interest are the Israeli aircraft, recently retrofitted with booms by IAI, and the Saudi aircraft, which are new build CFM56 powered KE-3A airframes bought to support the E-3/ F-15 air defence force. These aircraft also carry Beech 1080 pods to refuel the RSAF Tornado IDS strike force.

On the other side of the Iron Curtain, the Russians are currently phasing out older Mya-4 Bison tankers replacing them with new build II-76 Midas tankers to support their strategic force of Bears, Backfires and new Blackjacks. A widebody tanker is also expected, a derivative of the 11-86 Camber airframe.

Clearly all forward looking air forces today accept the necessity of an AAR capability in air operations, the humble tanker is indeed a potent force multiplier.

From the global perspective the RAAF’s tanker force (reported on in depth in the May AA)is modest in size and capability, but it is beyond any doubt a significant step in the right direction. With the currently benign regional environment and financially restrained mood in Canberra it will be difficult for the RAAF to make a strong case for a full size operational force of 8-12 boom, pod and fuel cell equipped tankers, however the increasing tendency toward instability throughout the Pacific and the growing power projection capability of India in the region could see changes further down the track. Much will depend upon our politicians’ perceptions of the situation, which excluding the notable exception of Kim Beazley, have always tended toward underestimating by a significant margin the potential for difficulties.

If future governments remain sincerely committed to helping maintain stability in the South Pacific and to the North of Australia, they will ultimately have no choice than to build up a substantial tanker/transport capability. Not to do so could invite the kind of situation we would all ultimately like to avoid.