Technology Explained- Fighter Upgrades Pt I

The political benefits of small numbers of highly skilled defence jobs are clearly seen by Western legislators as less important than the money to be saved and thus any growth in new airframe acquisitions is unlikely in the nearer future. Issues such as casualties in any future conflicts do not appear to enter this equation. The second clearly visible trend is the availability of considerable quantities of used but often very modern airframes, now surplus to the major powers’ needs. Excluding supersonic MiG purchases for under $100,000, the real issue is the availability of teen series and teenski series fighters at prices substantially below those of new airframes. From a commercial perspective, this constitutes market saturation and in effect ruining of the market’s established price structures, as governments eager to unburden themselves dump airframes on to the market. Shrewd players have capitalised on this situation, and the ADF’s recent acquisition of 15 F-111G airframes was a very good move indeed. Regrettably, the number could not be greater.

The trend toward decline in new airframe sales and the growing market in second-hand airframes has thus produced a growing market for overhauls and upgrades, and this could be said to be the third major trend visible in today’s marketplace.

Upgrades – The Technical Issues

Maintaining an older airframe or system in service presents some interesting challenges. Airframe fatigue and mechanical wearout of propulsion, hydraulic and accessory systems are steady consumers of replacement parts; as are wearout and random failures in electronic subsystems such as radar, communications, nav gear, cockpit displays and electronic warfare subsystems.

The major problem which is emerging is a shortage of spare parts. While structural and other mechanical components can be cannibalised readily from graveyard airframes or manufactured to order, due to the relative simplicity of the processes involved, this is not so with electronic components, which have evolved remarkably since the sixties. Whilst aircraft of same model designations but different production blocks may share a large fraction of common mechanical components, this tends not to be the case with electronic subsystems, which although possibly compatible at a subassembly level, are usually quite differently built at a component level.

This has been severely exacerbated by a trend since the 1970s toward manufacturing custom silicon for military equipment, rather than using military versions of commercially used chips, as well as the trend to competitively source such equipment from alternate vendors during longer production runs. Sourcing a specific 1960s power transistor or 1970s custom integrated circuit can be extremely difficult if not quite impossible. The rate at which this technology evolves in the computer and communications industries is such that equipment is often obsoleted and discarded in half a decade, and thus even the manufacturing processes for older components are no longer available.

The US DoD has now opened a facility which will manufacture custom components using current technology, to the electrical specifications of an obsoleted part, but this is relatively expensive and can render the support of a largely obsolete assembly quite expensive, particularly if the numbers involved are modest. The decision to proceed down this track is thus difficult, and turnaround times will by the nature of the process be prolonged.

The situation with Soviet equipment is even more painful, as the Russians had maintained manufacturing facilities for older technology while the aircraft were in service, rather than stockpile components. This reflected the maintenance philosophy of the Warpac, where low reliability was accepted and major overhauls of aircraft conducted quite frequently. The collapse of much of the former Soviet manufacturing base has caused something close to the collapse of the logistical infrastructure used to support the equipment. The prohibitive cost of maintaining older manufacturing processes has led in many instances to the effective disappearance of the plant in question. The Indian air force, as well as Eastern European air forces have suffered badly in terms of availability of components for types such as the MiG-29 Fulcrum.

The alternative is system-level upgrading with new avionics. This process involves typically a depot-level refit of the airframe, gutting part if not all of the original avionics and replacing these with new technology, and if applicable wiring harnesses. Airframe specific idiosyncrasies are then typically resolved in software. As with any such process, the customer can go through various levels of rebuild.

The Most Comprehensive Rebuilds

The most comprehensive rebuilds will see the fitting of new engines, accessory power, electrical system, wiring, avionic subsystems, and the zero timing of the airframe by the replacement of critical structural components and load-bearing skins. Whether the performance and capability of the aircraft are enhanced depends primarily on budgetary constraints. Matching an existing radar or avionic capability with new technology is typically cheaper than the original acquisition. Enhancing capability may cost more.

The payoff will be in vastly reduced maintenance costs, as the latest two generations of military avionics have seen reliability increase considerably, although it is argued by some that seemingly perennial software bugs have compensated for diminished hardware unreliability. The big winners in this process have been the smaller systems integrators, who have traditionally supplied avionic subsystems and software integration services to the prime contractors. Contractors in the UK, France, Israel and the US have quickly moved to exploit this market, and any defence journal today is bristling with advertisements for services and specific upgrades.

Usaf And Usn Upgrades

The United States Navy is facing the prospect of block obsolescence across much of its aircraft fleet, a situation which has been severely exacerbated by a series of what are arguably ill-considered programme cancellations. The Navy’s frontline outer air battle fighter, the F-14A, was to have been partially replaced by digital F-14Ds, with the remainder of the fleet to have been re-engined and partially upgraded to F-14B configuration. A heated debate had developed over the replacement of the F-14 with the NATF, a navalised derivative of the USAF ATF, with contractors proposing various configurations of F-14 upgrade.

The result has been the end of F-14D production, deployment to the fleet of jammer-less airframes, and an aging fleet of TF-30 powered F-14As in fleet squadrons. It is unclear at this time as to what further upgrades the Tomcat will be subjected to, although a role shift to encompass strike as well as air superiority suggests that laser designation and night vision equipment may eventually be fitted.

The A-6E Intruder was to have been upgraded to A-6G standards to fleet squadrons. The A-12 died a messy death at the hands of the Bush Administration, its would-be successor the AX never went beyond the vapourware phase and at this time no successor to the aircraft seems to have been agreed upon. As the A-6G upgrade was cancelled, only a limited rewinging programme remained to keep the aircraft in service until the turn of the decade. Clearly by that time the aircraft will no longer be viable tactically so it is fair to say that the USN will lose its long-range precision strike capability.

The /A-18 appears to have the best prospects for survival on the carrier flight deck, although it is unclear what will happen with earlier model A/B aircraft as the F/A-18E/F phases in at the end of the decade. Whether these will be brought up to the C/D avionic and systems standard has not been publicised.

The United States Air Force has similar pains with a large fleet of seventies-built fighter aircraft. The F-15A/B models have reportedly suffered availability problems due to the increasingly difficult to support APG-63 air intercept radar, state of the art seventies technology built with a large fraction of custom components. It is unclear as to whether any of the fleet will be upgraded. The C/D model fleet was upgraded to MSIP standard in the first half of the eighties, this involving an APG-70 radar, upgraded mission computer and various avionic subsystem upgrades. The C/D model Wings will have their role expanded to encompass SEAD, the traditional Wild Weasel role, and many will be fitted with an emitter locating system and wired for HARM missiles. There is much debate in the EW community as to the wisdom of imposing a high workload two-man mission upon a single pilot, but the US DoD seems to be determined to have its way.

The F-16 Falcon fleet is similarly aging, with many of the older A/B airframes assigned to Air National Guard squadrons. The USAF had originally planned a comprehensive avionics upgrade to the A/B airframes to equip them as replacements for the A-10 Warthog in the CAS role, this including a helmet steered thermal imaging turret projecting on to the pilot’s visor, and comprehensively upgraded communications gear. This did not eventuate.

Two hundred and seventy-nine Block 15 airframes were refitted in the late eighties to ADF standard with provisions to carry AMRAAM, including the AMRAAM datalink, an improved APG-66 radar, GPS navigation and improved communications including the ARC-200 HF/SSB radio. Many older aircraft were retrofitted to F-16A-OCU standard in the late eighties, the upgrade involving primarily RLG INS, software upgrades and support for BVR missiles.

Mid-1991 also saw the beginning of the Mid Life Upgrade programme for 553 airframes. The upgrade involved fitting a Block 50 C/D model style cockpit, wide angle HUD, NVG compatible lighting and displays, a new mission computer, a digital terrain system, provisions for FLIR night vision equipment and a microwave landing system.

The venerable F-111 will soldier on in the USAF, as it appears. The deployment of the F-15E saw the older model F-111E, F-111D and F-111G retired, leaving the F-111F and EW EF-111A in service, operations consolidated in the single overstrength 27th TFW at Cannon AFB in New Mexico. Interestingly, the USAF’s leadership given the choice of retiring either B-52s or F-111Fs, opted to retain the F-111F due to its Pave Tack capability. Media reports in this country of the impending demise of the remainder of the fleet are alas somewhat exaggerated, particularly as the EF-111A jammers are the only assets of their kind and will thus continue in service for at least another decade or longer. Fears of the RAAF losing its spares access are therefore unfounded and one could argue the result of political mischief in this country, compounded by irresponsible mainstream media reporting.

The most bizarre proposal in relation to the F-111 is that recently suggested by a Canberra academic, that the RAAF’s newly acquired F-111G aircraft should be broken up for spares, so as not to upset our neighbours. In the context of mutually supporting regional defence forces, such a move would guarantee a measure of upset, and no doubt convince our neighbours that we are indeed quite irrational!

While the US and NATO countries are carrying out what are generally modest upgrades to their front line inventories, the situation is rather different with operators of second-tier export fighters, be they of US or Soviet origin. Most of these are in Asia, and that will be the subject of Part 2.