The capability gap emerging as US Air Force F-111s are retired highlights the aircraft's unique abilities.

Graham Warwick/ATLANTA

FAR-FETCHED IT MAY SEEM, but it is feasible that the US Air Force could be flying electronic-warfare versions of the McDonnell Douglas (MDC) F-18 early next century. That is one possible outcome of the USAF decision to retire its Grumman EF-111s and rely instead on Navy Grumman EA-6Bs for tactical-jamming support.

This, in turn, was the result of an earlier decision to retire the General Dynamics F-111 strike aircraft to save money - an example of the tough choices the USAF is having to make in the present budget environment. The F-111F is the service's longest-range precision-strike aircraft and its abilities will not be matched until the conventional-weapons capability of the Rockwell B-1B bomber is fully upgraded.

At Cannon AFB, New Mexico, retirement of the F-111s began in October, and all 74 remaining aircraft are to be withdrawn from service by October 1996. The USAF had planned to retire the 40 surviving EF-111s, also based at Cannon, by October 1997, but their withdrawal has been delayed by two years to give the Navy time to upgrade its EA-6Bs to support joint operations. After 1999, only Australia will still operate the F-111.

The F-111 was marked for retirement because of its high support costs, although Lockheed Martin argues that the figures used to justify the decision failed to take account of the money spent in recent years on upgrading the aircraft. Unfortunately, the avionics and engine upgrades were fielded too late in the aircraft's life to make much of an impact on its 20-year-average support costs.

Australia will benefit, as its F-111s are undergoing similar upgrades and are scheduled to remain in service, past 2015. The Rockwell avionics-update programme (AUP) for 21 Royal Australian Air Force F/RF-111Cs is based on the Pacer Strike upgrade for USAF F-111s, which has reduced operating costs by 8%, Lockheed Martin says, and is similar to the earlier avionics-modernisation programme (AMP) for USAF FB-111s, which increased weapon-system reliability by a factor of five.

In addition, Australia has acquired 15 ex-USAF F-111Gs (formerly FB-111As) to keep its F-111 force viable into the next century. These already have the AMP updates and will receive the digital flight-control system, which is part of the AUP upgrade.

It is hoped that these aircraft, coupled with a USAF offer to sell Australia most of its stock of F-111 spares at 10% of the inventory cost, will reduce the burden of the country being the only operator of the type.


Paradoxically, retirement of the F-111 comes as the USAF is working to improve its interdiction capability with the introduction of advanced precision-guided munitions. The departure of the long-range, precision-strike, F-111 will increase the service's reliance on the MDC F-15E, the Lockheed Martin F-16 and F-117, the Rockwell B-1B and the Northrop Grumman B-2 - supplies of which are finite and, in some cases, dwindling.

The F-117 and B-1B are no longer being produced, while production of the F-15E for the USAF ended in 1994, the last USAF F-16 on order will be delivered in 1997 and B-2 production remains capped at 20 aircraft.

MDC says that production of the F-15E was "arbitrarily" halted at 209 aircraft and that, because of attrition, the USAF is already "a couple of aircraft short" of its requirements. With the resumption of production for Saudi Arabia and Israel, MDC has submitted an unsolicited proposal to build additional F-15Es for the USAF at under $50 million an aircraft.

The USAF has a stated requirement for 18 attrition replacements, and may receive funding for the first aircraft in its 1996 budget - thanks to a Republican-controlled Congress. These will be barely sufficient to cover expected attrition, for which MDC estimates the Air Force needs 20-36 aircraft. The 100 F-15Es, which the manufacturer says are needed to replace the F-111s are nowhere to be seen in Air Force planning.

What the USAF has said it needs are another 120 F-16Cs, to offset a shortfall expected early next century as a result of attrition and obsolescence. Again, funds for an initial batch, may be included by Congress, in the 1996 budget. That would allow USAF deliveries to resume in 1998 after a brief hiatus and before the F-16 line shuts down - which would be in 1999, based on firm orders in hand from foreign customers.

In addition to buying new aircraft, the Air Force plans to begin upgrading existing F-15s and F-16s around the year 2000. Potential upgrades have been identified under USAF Air Combat Command's fighter-configuration plan (FICOP). This plan, which is still being refined to make it affordable, identifies survivability, lethality and operability upgrades needed to allow the aircraft available to perform the missions required to accomplish US military strategy over the next 25 years.

For the multi-role F-16, the FICOP lists a menu of upgrades for those aircraft used in the different mission areas: Block 30 F-16s would be upgraded for the day-interdiction/close-air-support (CAS) mission, Block 40s for night-interdiction/CAS and Block 50s for day-interdiction/air-defence-suppression. The FICOP upgrades, if they materialise, would consist of a fourth multi-stage improvement programme (MSIP) for the F-16.


While Lockheed Martin and MDC are working to price the various upgrade options for their respective aircraft, they are also trying to interest the Air Force in derivatives, which could replace the F-111. Lockheed Martin has flight-tested an extended-range F-16ES configuration rivaling the F-15E and, under the designation F-16X, has proposed a delta-wing derivative with even longer range.

MDC, meanwhile, has offered a "big-wing" F-15E with 36% more internal fuel capacity, a 60% greater combat radius and increased weapon-carriage capability. While the F-15E has a radius of 25% less than that of the F-111, the company calculates, the big-wing aircraft would have a radius 10% greater than the F-111's.

Whether either design materialises will depend on the outcome of two new-aircraft programmes under way for the USAF - the Lockheed Martin/Boeing F-22 and the Joint Advanced Strike Technology (JAST) project, reportedly soon to be renamed the Joint Strike Fighter (JSF).

The tri-service aircraft planned to emerge from the JAST programme is scheduled to begin replacing USAF F-16s in 2010. Although recent reports have suggested that the USAF wants to bring service entry forward to 2007, money will not be available earlier unless the service reduces F-22 procurement from the planned 442 aircraft.

Air Force support for the F-22 has been firm, so far, and the service is already funding Lockheed Martin/Boeing to study potential derivatives for roles such as interdiction, defence-suppression and reconnaissance. MDC argues that the latter roles, at least, could be conducted using F-15Cs displaced from the air-superiority arena by the F-22, and upgraded with multi-mission capability.

While it appears unlikely that the USAF would sacrifice any F-22s to accelerate the JAST/JSF programme, such a move could reduce the near-term requirement for additional F-16Cs. There have been reports that the Air Force is considering upgrading 120 F-16As instead, using the mid-life update under development for European F-16A/Bs, but this option has yet to appear in any published USAF plan.

Officially, the USAF plans to fulfil the F-111's mission with the B-1B, once the bomber is capable of delivering precision-guided munitions. A phased conventional-mission upgrade now under way will lead to full clearance with laser-guided bombs by August 1997, almost a year after the F-111 is withdrawn - and only with off-board laser-designation.

The autonomous Joint Direct Attack Munition (JDAM) is to be available on the B-1B by late 1999, a year or so behind the B-2, with the unpowered Joint Stand-Off Weapon, Joint Air-to-Surface Stand-off Missile and Wind- Corrected Munit- ions Dispenser following by the end of 2002.

Rockwell is proposing an interim precision-guided weapon, which could be available on the B-1B early in 1997, ahead of the JDAM. This consists of a global-positioning-system (GPS) tail-kit for the Mk82 220kg bomb, which increases its accuracy to within 15m (50ft). While the USAF has no formal requirement for the weapon, it has ordered an interim precision-guided munition for the B-2.

The Northrop Grumman GPS-Aided Munition (GAM) is to be operational on the B-2 in July 1996, more than a year ahead of the JDAM. The GAM is a GPS tail-kit for the Mk84 900kg bomb, which provides 6m accuracy when coupled with a GPS-aided targeting system (GATS) in the B-2. The GATS uses synthetic-aperture-radar images to remove errors in the target GPS-position loaded into the weapon before launch.


While the USAF juggles its options to replace the F-111, the decision to hand the EF-111's jamming role over to the Navy has already been taken. The first USAF crews joined an EA-6B unit at NAS Whidbey Island, Washington, in October, although present plans call for EF-111s to be retired beginning in late 1996, with 20 aircraft remaining in service until late 1999.

The delay was necessary because Navy EA-6Bs need upgrading to support the Air Force, possibly with elements of the now-cancelled EF-111 system-improvement programme. In the longer term, Air Force leaders admit that it is possible that the services could develop a common electronic-warfare aircraft to replace the EA-6B.

The most likely candidate, at least from the Navy's viewpoint, is the proposed command and control warfare (C2W) variant of the new two-seat F-18F. MDC and Northrop Grumman have joined forces to pursue development of this aircraft, which would use elements of the cancelled EA-6B ADVCAP advanced-capability upgrade.

The F-111 started out as a joint US Air Force/ Navy aircraft. It is ironic that its retirement may succeed, where the original programme failed, in bringing the services together.

Source: Flight International