Technology Explained- US Tactical Aviation Pt 11

The design concept of the ATA dates back to the early eighties, when John Lehmann was Ronald Reagan’s Secretary of the Navy. John Lehmann, a naval reservist A-6E Bombardier/Navigator, was a strong supporter of carrier aviation and one of the co-architects of the US Navy’s then new MaritimeStrategy. A key aspect of the strategy was a very aggressive naval posture toward the Soviet Union. In the event of a major war with the USSR, the US Navy would sail its CVBGs (CarrierBattle Groups) North into the bear’s lair and engage the Soviets in their declared naval bastions, the areas immediately surrounding the Kola Peninsula in the Atlantic and the Kamchatka/Sakhalin area of the Far East. A two phase battle was envisaged: initially the USN would engage the AV-MF (Soviet Naval Aviation) and heavily attrite if not annihilate its force of Backfires, Badgers and Bears. Once this had taken place, the carriers would move to within 400nm of the coast and subject Soviet coastal installations and naval forces to sustained air attack.

The strategic plan envisaged ultimately the destruction of the Soviet surface fleet, followed by the sinking of its large SS/SSN/ SSGN (submarine/nuclear attack submarine/cruise missile firing submarine) fleets and the hunting down of its SLBM (submarine launched ballistic missile) firing SSBN (strategic ballistic missile firing submarine) fleet. The absence of serious Soviet air capability in the latter phase of the battle would allow the USN’s SSNs and surface fleet to effectively annihilate the Soviet submarine force, while also destroying its vital support infrastructure and resupply system. As a result, the V-MF (Soviet Navy) would be clearly on the defensive and unable to pursue its principal role, the cutting of Allied shipping lanes. In addition, the Soviets’ second echelon nuclear deterrent, the SSBN fleet, would be largely sunken or at least operationally crippled.

However, for the Maritime Strategy to succeed, the US Navy would have to initially defeat the AV-MF without suffering substantial losses in carriers or aircraft. The AV-MF’s principal maritime strike aircraft is the Tu-22M Backfire B/C, a supersonic swing wing bomber equipped with Mach 3 AS-4 Kitchen or AS-6 Kingfish anti-shipping cruise missiles (A A July, 1988 in detail). The Backfire has a combat radius of 2,500nm, much more than the 1,500nm of the obsolete Badgers and Blinders which it is replacing. Therefore, unlike its predecessors, it can attack a CVBG at substantial radii. The 1,500nm radius of the Badger and Blinder was a serious operational constraint. The Soviet view of defeating a CVBG on the high seas is one of massed saturation ASM attacks from several axes, to disperse the defending fighters and thus prevent them from destroying the inbound bombers and ASMs once launched. With a 1,500nm Badger/ Blinder radius the CVBG must be within 500nm of the coast for these bombers to have freedom of choice in axis of ingress to target; at greater radii the bombers have increasingly less choice and thus are subject to increasing concentrations of defensive SAM and AAM fire. The Backfire extends this kill zone out to about 1,000nm. However, another aspect of the Soviet response to the Maritime Strategy has been the deployment of the long legged Su-27 Flanker to the Kola and Kamchatka Peninsula, supported by Mainstay AWACS. With a combat radius of the order of 750nm, the Flanker could disrupt a substantial portion of the USN’s F-14 force, preventing them from engaging inbound bombers and ASMs and thus substantially reducing the concentration of defensive fire.

Clearly, if confronted by a CVBG, the V-MF could choose not to engage until the fleet had closed to a radius where the V-MF could apply its strike assets to best advantage. This would almost certainly be within the 500-700nm kill zone radius where the older bombers could be used, and fighter/AWACS support was available. Under these conditions, any contest would be a closely fought win, as the Soviets could apply their assets in the best possible way, while the CVBG would be very limited in its offensive options. The losses on both sides would be horrendous.

The ATA was conceived to swing the balance in this scenario in favour of the USN. Clearly it would be necessary for the USN to force an engagement with the V-MF for the Russians to engage on less than favourable terms. Forcing the commitment of major assets to a high risk engagement would require a major incentive, and the USN saw this in sustained air strikes against high value assets, including the Backfire, Mainstay and Flanker forces on the ground, and key air defence and naval facilities. The capability to apply such pressure from outside the V-MF’s best striking radius is not available with existing aircraft. Only the A-6E with inflight refuelling has the radius for such a mission, but its survivability in the face of AWACS directed Flankers, Fulcrums and SA-10 SAMs is not worth contemplating. A stealthy strike aircraft could however bypass such defences, as was repeatedly demonstrated by the F-117A over Baghdad earlier this year.

This scenario therefore determined two key aspects of the ATA’s design, a combat radius of the order of 1,000nm and all aspect stealth in the face of fighter and SAM defences. Another capability embedded in the ATA specification was the ability to carry the full complement of AAMs, as this would allow the ATA force to be ‘swung’ into the air defence role to supplement the F-14s and F/A-18s engaging inbound ASM firing bombers.

The GD/MDC A-12A Avenger 2 Advanced Tactical Aircraft

The General Dynamics/McDonnell Douglas A-12A Avenger 2 was to be a unique trendsetter, being the first ever naval aircraft designed from the outset for stealthiness. The program was shrouded in secrecy from the outset, being a fully ‘black’ project from its conception. Given the strategic importance of the ATA in

The implementation of the Maritime Strategy, this is hardly surprising. The US Navy had originally sought 858 A-12s, to replace the existing A-6 fleet and to bring the long range strike complement of the standard CVW to 20 aircraft, consistent with the new generic wing structure of 20 x F-14, 20 x F/A-18 and 20 x A-6 or ATA. This was cut late last year to 620, the Navy settling for 16 ATAs per CVW in the interim.

The ATA was to be built by a Genera/ Dynamics/McDonnell Douglas contractor team, structurally unusual in that the two largest defence contractors in the country were teamed with equal contributions rather than competitive. This arrangement was subsequently proven to be less than suitable, as MDC and GD have always maintained a very competitive mutual relationship.

Almost nothing was stated publicly about the program until September last year, when the Navy released the first artists’ renderings of the aircraft and limited technical data. This occurred primarily due to budgetary pressure, as the USN did its best to demonstrate the case for the aircraft. Nicknamed the Dorito, the ATA design was a very clean delta flying wing, with a two place tandem cockpit and its two 14,000lb class non-afterburning GE F412s embedded in the lower fuselage. A three lobed stealth design with no tail surfaces, the ATA relied upon the differential drag produced by split wingtip speedbrakes to provide yaw control. As a flying wing, the aircraft would have had limited AoA capability, without a tail to provide the nose up pitching download, and therefore required much greater wing area to provide acceptable approach speeds for recovering on a carrier deck. The total wing area of 1,300 square feet (120. 9m2) is twice that of similarly sized current naval aircraft, which also translates into far greater aerodynamic efficiency in cruise.

The low wing loading also provides superb turning performance, with both instantaneous and sustained turn rates estimated to be comparable to an F/A-18. The wing has outboard leading edge devices, and substantial outboard trailing edge flaps, but it is unclear how effective these would be given the need to reconcile the pitching moment associated with flapswit, h the tailless design. The central beavertail surface may have been employed for such pitch trimming. The trapezoidal inlets are recessed into the lower leading edge of the wing, feeding the F412 fans via long and hence stealthy inlet ducts. No pictures were released of the exhaust geometry, but it is reasonable to assume these are implemented as horizontal slits, using a similar technique to that in the F-117. The F412-GE400 was derived from the F404 of the F/A-18, but employs a much bigger fan with a lower pressure ratio,increased air flow and improved resistance to FOO. The compressor employs a new blade design and delivers more airflow than its predecessor. The high pressure turbine was redesigned aerodynamically and uses improved materials, while the low pressure turbine was derived from the design used in the F110, from which the F412 also borrowed a digital electronic control unit.

The aerodynamic design, large internal fuel fraction and modern powerplants would have provided the A-12 with excellent payload radius performance. In comparison with the A-6E it was to replace, the A-12 offered a better than 70% increase in payload radius performance and a 40% greater payload capacity. Similarly, acceleration performance was better, the USN claiming a loaded A-12 could accelerate 30% faster than a clean A-6E, this being no doubt due to the low wing loading and low drag of

The blendea airframe. The offensive avionic suite planned for the A-12 was no less impressive. A Westinghouse AN/APO-183 multimode radar with phased array antennas, visible on the outboard leading edge, would provide a wide range of high resolution ground mapping and sur face search modes, while also suppblting the AIM-9, AIM-120 and later advanced air-to-air missiles. The offensive avionic suite also included an electro-optical sensor package in the nose of the aircraft, this including a Flir device for navigation and targeting. The geometry of the aircraft suggests that a turret like that of the F-117A was mounted ventrally to track and illuminate targets attacked with semi-active laser homing munitions. The defensive suite was to be built around a highly sensitive combined Radar Warning Receiver/Electronic Suppor t Mea sures (RWR/ESM) system, a first of its kind. Conventional RWRs are optimised for the short range detection of terminal threats and therefore are designed with low sensitivity to preclude spurious false alarms. ESM systems are more sensitive than RWRs as they are employed to sniff for hostile emissions at longer ranges, this optimisation usually results in poor response time and severe limits on the number of concurrent tracks. The A-12’s RWR/ESM was to have integrated both capabilities thus providing the aircraft not only with a long range threat warning system, but also with a potent electronic recce sensor. It is very likely that the USN planned to integrate this system into the datalinked fleet wide BGPHES network (Battle Group Passive Horizon Extension System- a scheme whereby long range electronic recce platforms such as the EA-3 and EA-6B can datalink passive target tracks to other aircraft and surface ships).

The ATA program developed visible problems late last year, as the design was 8,000lb over its target weight. In an aircraft with an empty weight of the order of 35,000lb, this was a serious problem and would require either a major structural redesign or the installation of bigger powerplants, in turn also requiring substantial structural redesign.

The development contract which was signed in January 1988 for the building of 8 development airframes was a fixed price contract worth $US4,800 million and the DoD subsequently estimated that design changes would inflate this cost to $US7,500m. Pressure mounted on the USN late last year, after reports that the Navy had repeatedly underestimated cost overruns and schedule delays. This was very damaging politically, as only weeks prior to these statements a Major Aircraft Review was carried out and the DoD were advised that all was well. The USN subsequently dismissed the head of Naval Air Systems Command, responsible for the project, and reassigned the project manager. Reports from the US indicate that the DoD reviewers had in fact paid more attention to project objectives than the actual state of the development work done to date.

This was apparently compounded by the “black” classification. status of the program, which meant that many DoD mechanisms for checking project progress were inoperative due to the potential for security leaks. The compartmentalised nature of any ‘black’ program would itself have caused difficulties in assessing progress in many areas, as few individuals would have been cleared for access to the range of information required to pass a reasonable judgement.

Pressure mounted and on 7 January this year the DoD announced the termination of the program, after meetings between the DoD and contractors where Defence Secretary Cheney was advised that additional funds would be required to complete the program. Cheney, at the time deciding under intense budgetary pressure from the Gulf campaign, stated the following: “This program cannot be sustained unless I ask Congress for more money and bail the contractors out. . . and I do not belleve a bailout is in the national interest. . . if we cannot spend the tax- payers money wisely, we will not spend it”, while acknowledging the Navy’s pressing need for a stealth technology strike aircraft. By the time of cancellation, over $US3 billion had already been invested in the ill fated project.

At the time of writing GD and MDC were considering legal action against the US government to recover $US1. 6 billion in costs incurred and losses, while the US government was considering similar action to recover $US1. 9 billion which it believed the contractors owe the government due to overpayment.

The A-12 had fallen victim to the ambitious design objectives which much like the USAF’s SOR-183/ TFX (F-111) in the 1 960s, stretched the technology of the day to the limit. The contractors have correctly pointed out since, that high risk is inevitable if the technology of the day is to be pushed, and that the DoD must accept the implications of this. A GD press release stated: ” . . . A-12 development problems have been the direct result of government insistence on a fixed price contract for a program that is on the cutting edge of technology”. Estimates at the time suggested the loss of up to 10,000 defence industry jobs as a result of the cancellation.

The combination of ‘black’ security status, non-competitive development via a fixed price contract, and lack of oversight created a situation where any high risk development project is likely to have foundered. The argument that the contractors should have drawn attention to problems at an earlier date is quite naive, as it overlooks the sensitive political relationship which exists between a defence contractor and the contracting service. While the Navy must accept much of the responsibility for the project going off the rails, it was forced into this situation in the first place by funding shortages which prevented it from pursuing a fully competitive dual airframe flyoff such as that conducted for the USAF Advanced Tactical Fighter {ATF). Given the importance of the ATA to the USN and planned USAF ATA derivative airframe production to replace the F-111 fleet, it is therefore disappointing that US legislators had given so little forethought to the matter. The replacement for the A-12 is to be the AX, for which no funding has yet been allocated. The AX is planned to enter service in 2003, a full 40 years after the A-6 entered operational service, and early indications are that the design requirements have been substantially relaxed against that of the ATA. The AX may carry external payload, compromisirg stealth performance, and will have a mission radius requirement in excess of 700nm. This clearly indicates a major fear of incurring any technical risks, something which is already evident in the USAF ATF decision. The ATA cancellation sent political shockwaves through the US services, as contrary to some earlier expectations the very much conventional and hence low risk Lockheed and Pratt & Whitney ATF designs were selected in spite of acknowledged lower performance in a number of key areas, when compared to their technologically innovative Northrop and General Electric competitors.

In the interim, additional F/A-18s will be purchased and much of the serving A-6 force will be rewinged to keep them flyable. These very modest measures reflect the painful situation the USN has found itself in, as the acquisition of the AX rather than ATA will fall into the same timescale as the planned acquisition of the Naval AT F (NATF). This will result in a demand for substantial additional funding at that time to avoid the stretching of deliveries with associated losses in economies of scale, and to avoid the by then developing shortage of flyable tactical aircraft. The short term saving in expenditure achieved by the Bush administration in killing the ATA rather than fixing its design problems has only postponed the inevitable to a timescale where it is likely to be less affordable and hence even more painful. The first decade of the next century will see block obsolescence across much of the USN’s tactical aircraft fleet. It is worth noting that the A-12, much like the f-111/ TFX, ran into late development problems primarily due to the combination of advanced technology and very ambitious performance objectives. While the US had the economic strength in the sixties to follow through with the TFX project and ultimately produce one of the most capable strike aircraft ever built, a top performer in a front line engagement 27 years after its first flight, the current budgetary situation in the US combined with the political background to the project prevented the A-12 from following a similar path.

Part III reviews the F-140 and the proposed F/A-18E/F and their respective weapon systems.