Self Defence

Lon Nordeen and John Quigley conclude their report on the evolution of aircraft self-protection systems over the past three decades.

IN THE second, concluding part of this self-defence system article, the authors review Electronic Attack, Electronic Warfare Support, Suppression and/or Destruction of Enemy Air Defences (SEAD/DEAD) and the application of GPS-guided weapons in those roles.

Electronic Attack

This activity involves jamming or deceiving an adversary’s radar or radio communications. Jamming aircraft such as the US Air Force EB-66, US Navy EA-1F, EKA-3B plus US Marine Corps EF-10 and EA-6A added an electronic ‘punch’ with which to suppress North Vietnamese surveillance and Surface-to-Air Missile (SAM)/Anti-Aircraft Artillery (AAA) tracking radars. These Electronic Warfare (EW) platforms significantly reduced the capability of North Vietnamese air defence systems to track and target US aircraft, thus lowering losses over North Vietnam. Towards the end of the war in Southeast Asia, the US Navy introduced the EA-6B Prowler (170 were eventually built), a dedicated four-seat jamming aircraft equipped with the AN/ALQ-99 tactical jamming system. In the late 1970s, the US Marine Corps transitioned its EA-6A Electric Intruder fleet to Prowlers. In 1981 the US Air Force upgraded the first of 42 F-lllAs into EF-111A Raven, with a modified version of the ALQ-99 system but with a two-man crew, to replace the EB-66 Destroyer. The EF-111A had excellent range and speed, including supersonic dash capability. By comparison, the slower EA-6B can loiter for long periods of time and carries the ACM-88 High-speed Anti-Radiation Missile (HARM) so the Prowler performs both jamming and defence suppression missions. Both these platforms served with distinction in the 1991 Gulf War. Stand-off jamming was required for F-117 missions over heavily-defended targets deep in Iraq and employed for nearly every major strike.

Ravens Retire

In 1998, budget cuts led to the retirement of the US Air Force EF-111A force and the US has since counted on the EA-6B Prowlers from the US Navy and Marine Corps to perform the entire joint mission. Prowlers are a part of each US Navy aircraft carrier battle group deployment.

Intensified operations over Bosnia and Kosovo and ongoing commitments in Afghanistan and Iraq have tasked the ageing Prowler force to the limit. Today over 100 Prowlers are assigned to 14 US Navy and four US Marine Corps squadrons. However, avionics problems, overhaul, upgrades and other challenges on an average day mean than fewer than 60 Prowlers are able to fly and many of these are limited to less than 4g due to fatigue limitations. The EA-6B fleet has been expanded to deal with the heavy tasking: former EF-111 crews were assigned to US Navy Prowler squadrons, and crews now have Night Vision Goggles for improved capability. From the beginning of 2005, a limited number of Prowlers were upgraded with new capabilities via the installation of the Northrop Grumman Improved Capability III configuration, which adds the ALQ-218V(1) receiver suite, greater processing capability and the Link 16 and other data modes.

New Generation Electronic Attack

The US Department of Defense (DoD) conducted an extensive Analysis of Alternatives in 2000-2001 with a view to best fielding Airborne Electronic Attack (AEA) capability beyond the year 2010. In 2002 DoD approved a joint services plan for an AEA System of Systems. The US Navy elected to invest in the development of the EA-18G Growler to replace its carrier-based EA-6B Prowler force. The Navy’s land-based expeditionary squadrons would be deactivated following the introduction of new US Air Force systems — a B-52 Stand-Off Jammer and the Joint Unmanned Combat Air System (JUCAS). The EA-18G would fill the ‘mod escort’ role while the B-52 would provide high-power stand-off jamming and the low observable and unmanned JUCAS suppress the more sophisticated air defence threats from close range.

Boeing and Northrop Grumman began research for an electronic attack version of the F/A-18F Super Hornet in 1993 and most of the major systems, such as the ALQ-99 pods, enhanced rear crew station displays and internal avionics layout, were initially tested before formal development began. A modified version of the two-seat F/A-18F Super Hornet — the EA-18G Growler — carries the ICAP III receiver system in the gun bay, wide band RF antennas on the wingtips and ALQ-99 pods under the wings and centreline. The Growler will retain all the basic capabilities of the Super Hornet, although initial weapons carriage will be limited to self-defence air-to-air missiles and HARM. The first development EA-18G, designated EA-1, began flight tests in August 2006: it is scheduled for Initial Operational Capability (IOC) in late 2009.

In late 2005 the Air Force cancelled both the B-52 SOJ and JUCAS programmes. DoD is currently reviewing its options for recapitalising its AEA force structure. Although the System of Systems concept is still considered valid, several specific platform and system options are being looked at. The earliest any option could be selected and funded is Fiscal Year 2008.

Electronic Warfare Support

To suppress the air defences of an adversary, you first have to know what systems they have and how they operate. This has been developed to a high art during the Cold War, and since the Vietnam War a massive amount has been spent in the US to develop a comprehensive intelligence collection capability. There are dozens of SIGINT (Signals Intelligence) satellites in orbit at any time, and US RC-135, U-2, EP-3, RC-12 aircraft and unmanned systems, such as the Global Hawk and Predator, support these. Britain, France, Germany, Israel and many other nations are known to have transport-type aircraft equipped to perform SIGINT missions. The data collected is used to maintain an electronic order of battle and a list of potential adversaries — a critical element of electronic warfare planning.

Suppression/Destruction of Enemy Air Defences

To suppress and destroy SAM and AAA batteries during the Vietnam conflict, the US Air Force developed Wild Weasel F-IOOFs, F-105Gs, and F-4Cs, while the US Navy fielded Ironhand A-4s, A-6s and A-7s equipped with special receivers that could seek out surveillance, SAM guidance and AAA radars and knock them out with AGM-78 Standard and AGM-45 Shrike anti-radiation missiles, bombs and rockets. These systems fought a long-term battle with North Vietnamese air defences, which resulted in a reduced number of US aircraft losses. In 1982 Israeli forces employed unmanned decoys to stimulate the Syrian air defences to turn on their radars to provide targets for air and ground-launched Standard anti-radiation missiles. Fighters then flew in and bombed missile sites deployed in the Bekaa Valley and along the Lebanese border. This assault was so successful that the Syrian high command was forced to throw its MiG-21 and MiG-23 pilots into action against experienced IDF/AF F-15 and F-16 pilots, resulting in a staggering 86 to 0-loss rate in air combat.

A SEAD campaign involves a mix of tactics and weapons. Decoys such as BQM-74 Chukar drones and ADM-141A TALDs (Tactical Air Launched Decoys), used in the Gulf War, and the Northrop Grumman Miniature Air Launched Decoy (MALD) were employed in Bosnia and Iraq to simulate a major air strike to force the adversary to activate its air defences. US F-4Gs, A-7s, F/A-18s, F-16C)s, EA-6Bs and German Air Force Tornado ECRs (Electronic Combat/Reconnaissance) have fired more than 4,000 AGM-88 HARM missiles during Operation Desert Storm, over Bosnia and Kosovo, and in continuing operations over Iraq and in Afghanistan, to suppress or destroy radars. The UK fields the similar ALARM (Air Launched Anti Radiation Missile) system on its Tornado GR.4s. Russia has fielded many similar systems, such as the Kh-25 (AS-10 Karen) and the Kh-28 (AS-9 Kyle).

In the Gulf War, Operation Allied Force over Kosovo and Serbia and Iraq, US Air Force F-117s (and B-2s in Allied Force) struck command and control centres and other critical air defence nodes with laser-guided and JDAM bombs in the defence suppression role. Tomahawk and Conventional Air Launched Cruise Missiles (CALCMs) were also directed against important elements of the air defence network, such as surveillance radars, missile sites and command bunkers. NATO and US aircrew followed up with laser-guided and TV/Electro Optical-guided bomb and missile strikes against air defence sites and other targets in all of the conflicts since Desert Storm. Although short-range TV-guided and laser-guided bombs and missiles are useful in the SEAD role, they are not without drawbacks. Both free-fall weapons and short-range missiles must be launched within a relatively narrow ballistic path toward the target. Since most laser and TV/IR (Television/ Infra-Red) guided bombs and short-range missiles must be dropped from medium altitude and in good weather, the launch and guidance aircraft are potentially vulnerable to SAMs and heavy AAA.

GPS Guided Munitions

Following the Gulf War, the US DoD awarded study contracts to develop a number of new air-to-ground munitions. One of these was the Joint Direct Attack Munition (JDAM). This is a low cost guidance kit, fitted to free-fall 500, 1,000 and 2,0001b (227, 454 and 907kg) bombs to improve their accuracy to a Circular Area Probable (CEP — a predicted miss distance) of less than 40ft (12.19m). This tail kit includes a guidance unit, Global Positioning System satellite receiver, rear control fins, and strakes to extend bomb range. The JDAM is a free-fall weapon, but from high altitude the bomb has a range of more than 8 miles (13km). Though less precise, a JDAM is accurate to within 40ft (12.2m) compared to a laser-guided bomb (to within 15ft [4.5m]), and can be used in all weather conditions.

During Operation Allied Force, US Air Force B-2 bombers dropped up to 16 JDAMs with impressive accuracy through poor weather and clouds. JDAM is now deployed on US and allied strike aircraft, such as the F/A-18 and F-16. Another new weapon first used in the defence suppression role over Iraq was the AGM-154 Joint Stand Off Weapon (JSOW) which employs GPS guidance and a cluster munitions payload. The first US Air Force F-15E unit, the 48th Fighter Wing based at RAF Lakenheath, Suffolk, UK, dropped the first GBU-39 Small Diameter Bombs (SDBs) over Iraq in September 2006. The SDB is a 2501b (113kg) GPS guided weapon with a wing kit, which allows for stand off attack from more than 20 miles (32km) away with limited collateral damage.

Dozens of air-to-ground guided missiles in service around the world can, and have, been employed in the SEAD role, and these are divided into categories by range and payload. Relatively short-range systems like the French AS-30L, US AGM-65 Maverick and Russian Kh-23 (AS-7 Kerry) and Kh-25 (AS-10 Karen) are classified as stand-off outside point defence (SOPD) weapons. The Maverick and AS-30L rocket-powered missiles allow strikes from outside the range of guns and shoulder-fired SAMs. The 462lb (209kg) Maverick operates with a TV, IR or laser seeker while the AS-30L uses a laser seeker. IDF/AF F-4E crews first used the Maverick missile in action in 1973, towards the end of the Yom Kippur War. Iraqi jets also used both the Russian Kh-23 and AS-30L with a high rate of success in the Iran-Iraq War. US Air Force A-10 pilots fired more than 5,000 Mavericks during the Gulf War.

Longer-range precision-guided weapons carried by aircraft are known as stand-off outside area defence (SOAD) systems, and these can be fired from beyond the reach of area defence SAMs like the SA-2 (Guideline). SOAD used in recent conflicts include the 60-mile (96km)-range US Navy Standoff Land Attack Missile (SLAM) and 150-mile (241 km)-range SLAM-Expanded Response (ER), both a derivative of the AGM-84 Harpoon anti-ship missile, with TV terminal guidance and a data link for precise control and damage assessment. Long-range US Navy Tomahawks and USAF CALCM cruise missiles fired from US Air Force B-52 bombers were also used in the air campaigns over Kosovo/Serbia, Afghanistan and Iraq. The Israeli AGM-142/Popeye, UK Storm Shadow, German KEP350 Taurus, Russian Kh-59M (AS-13 Kingbolt) and US AGM-158 Joint Air to Surface Stand Off Missiles (JASSM) are similar weapons in service or advanced development.

Technology Revolution

A revolution in technology is now dramatically changing the nature of warfare, especially in the air. The rapid scientific and technical advancements in computers, electronics, information processing, sensors, weaponry and aircraft were demonstrated in recent conflicts such as Kosovo/Serbia, Afghanistan, Iraq and Lebanon where electronic warfare played a vital role. Considerable research is going on to develop sensors and command and control systems which will identify potential air defence threats in near real-time and direct weapons to destroy a SAM or fighter before it can escape.

Another trend worth noting is the need to employ electronic warfare technologies and techniques against the asymmetric threat posed by insurgent groups and terrorist organisations. Technologies once reserved for traditional strike and defence suppression operations are being used to counter threats to ground forces. Systems and platforms once solely employed in the SEAD mission are now being used against an ever-expanding variety of threats, which are evolving at a rapid pace due to the proliferation of wireless communications and advanced computing capability. The threats posed by advances in traditional anti-aircraft systems obviously require consistent advances in countering technologies. The asymmetric threat will also demand more attention and resources and will drive a continuing demand for additional electronic warfare capabilities.

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