Suppression of Enemy Air Defenses
Suppression of Enemy Air Defenses (SEAD), also known as "Wild Weasel" and "Iron Hand" operations in the United States, are military actions to suppress enemy surface-based air defenses, including not only surface-to-air missiles (SAMs) and anti-aircraft artillery (AAA) but also interrelated systems such as early-warning radar and command, control and communication functions. This suppression can be accomplished both by physically destroying the systems or by disrupting and deceiving them through electronic warfare. In modern warfare SEAD missions can constitute as much as 30% of all sorties launched in the first week of combat and continue at a reduced rate through the rest of a campaign. One quarter of American combat sorties in recent conflicts have been SEAD missions.
World War II
During World War II the German Luftwaffe attempted to destroy the Chain Home radar stations as part of the Battle of Britain in order to degrade Britain's air defense network. However, German High Command failed to realize the efficiency of not only the radar stations themselves but the command and control system directing Britain's air defenses. After initial optimism regarding the radar sites' destruction it was eventually decided to halt these attacks altogether except for exceptional circumstances. As the air war in Europe shifted in favor of the Allies, the Germans relied heavily on their AAA to defend against bombing attacks. This was borne out in Allied aircraft losses between 1943 and 1944, where losses to enemy fighters was cut in half but losses to flak increased tenfold.
Allied response to these developments were several. Understanding the importance of German radar sites the Allies directed attacks against these installations and introduced new technology to counteract the effects of radar-directed AAA including CARPET and WINDOW. A change in tactics saw bomber formations directed to fly higher and more spread out to avoid the effects of flak. Bombing missions were also carried out to accomplish the physical destruction of AAA sites, using imagery intelligence to locate the weapons and employing both heavy bombers like the B-17 Flying Fortress and fighter-bombers to destroy them. The P-47 Thunderbolt in particular was chosen for this task due to its ability to survive enemy fire. The effect of these missions varied, with losses suffered by fighter-bombers much higher—up to 40% in some cases—on account of their low-altitude attacks. Artillery also played a major role in suppressing air defenses, with the British Army the first to develop what became known as counterflak or "Apple Pie" missions. These missions were first employed to limited effect during the Battle of France but matured as the war progressed. The largest SEAD mission in history took place on March 24, 1945, when artillery forces of the British XII Corps attempted to knock out the local German air defense network in support of Operation Varsity. Although twenty-four thousand artillery shells were fired over the course twenty-two minutes at some one hundred targets, the mission was unsuccessful on account of inaccurate targeting data and insufficient firepower.
In the Pacific Theater the Japanese had made only limited progress in developing radar for air defense and what systems they did have were primitive and easy to avoid. Nevertheless as the Americans began the bombing campaign against Japan there was concern over the large number of radar sites located on the home islands. For this purpose B-24 Liberators and B-29 Superfortresses were fitted with radar-homing devices to conduct "ferret" missions to locate and identify radar transmissions. The information brought back from these missions was used to outfit other B-29s with radar jammers and chaff to confuse Japanese air defense radars as they conducted their missions. B-25 Mitchells were also outfitted with radar-homing equipment and used to lead "hunter-killer" teams of other B-25s in locating and destroying Japanese early-warning radar sites.
In the Korean War, SEAD was still an undefined mission, with the neutralization of air defenses based on its relation to specific targets or operations rather than as part of a larger strategy. Thus while technology changed, many of the tactics for dealing with enemy air defenses were very similar to previous war. For aircraft performing missions at low altitudes AAA remained a constant danger; in fact it was less dangerous for a UNC pilot to engage in air-to-air combat than it was to attack ground targets. The terrain and weather of the Korean Peninsula also contributed to the dangers associated with ground-attack missions. However the advent of jet aircraft brought about many changes. Compared to propeller aircraft jets were much faster, could climb more steeply, were more resistant to damage and were quieter in operation. They were thus able to more effectively attack ground targets and escape, and while both jet- and propeller-driven aircraft participated in the Korean War the latter suffered heavier losses and were largely phased out by the end of the conflict.
As the war progressed the Communists developed a highly centralized integrated air defense network, incorporating early-warning radars, ground-controlled interception and AAA. The potency of this network compelled UNC bombers to conduct bombing missions at altitudes beyond the reach of ground-based weapons although this impacted the accuracy of their bombs. The UNC also possessed an effective air defense network, however the NKAF had been largely destroyed early in the war and the PLAAF's almost exclusive mission was air superiority.
The Vietnam War saw the evolution of what would be known as SEAD over the course of the conflict. With the start of Operation Rolling Thunder, North Vietnam's air defenses were only dealt with in a piecemeal fashion in spite of intelligence indicating that the North Vietnam Army was developing an integrated air defense network dedicated to air deniability. This included the construction of sixty SA-2 Guideline SAM sites by the end of 1965 which, though only accomplishing one hit for every thirteen missiles fired, were responsible for shooting down nearly 15% of American aircraft lost that year. Early attempts to counter this system consisted of modified F-100 Super Sabers using crude homing equipment to locate and bomb radar-guided SAM and AAA sites, but these missions incurred heavy losses and the threat to American aircraft continued to grow. In 1966 a task force was put together to analyze the challenges presented by the NVA's air defense network and recommend ways to counter it. One of these was for aircraft to operate at low altitudes (below 500 meters) where the missiles were less effective. Unfortunately this also put the aircraft well within range of AAA, which would account for nearly 85% of all American aircraft losses during Rolling Thunder.
Eventually new SEAD aircraft were developed, the Air Force's EF-105F/F-105G Thunderchief and Navy's A-6B Intruder, which mounted more sophisticated detection equipment and carried the AGM-45 Shrike and AGM-78 Standard ARM anti-radiation missiles. These fighter-bombers became very adept at tracking down and destroying ground-based air defense weapons, such that eventually an overwhelming number of NVA SAM operators would chose to turn off their radars when an F-105G was spotted. While this prevented the SAM's physical destruction it essentially accomplish the same mission of suppressing air defense around the target. Electronic warfare aircraft were also used to suppress air defenses by jamming NVA radars, with first the EB-66 Destroyer joined later by the EA-6B Prowler. By the end of Rolling Thunder these changes had caused a significant degradation in the effectiveness of SAMs: only one SA-2 missile out of every forty-eight fired resulted in a hit. In spite of these developments SEAD would remained a primarily tactical function during Rolling Thunder, with American leadership either unaware or unappreciative of North Vietnam's integrated air defense structure.
Loses suffered by F-105 Wild Weasels spurred on the development of a new variant based on the F-4C Phantom II, the EF-4C Phantom Wild Weasel IV. The first thirty-six of these were delivered to Southeast Asia in 1969 and so missed taking part in Rolling Thunder. While carrying the same electronics as in the F-105G the dense internal structure of the F-4 Phantom prevented the EF-4C from efficiently mounting this equipment and the aircraft was prevented from carrying the superior AGM-78 Standard missile. By the start of Operation Linebacker Wild Weasel missions were both more and less effective. Tactics and technology had evolved which improved the suppression of individual SAM sites however the American military still failed to account for the fact that North Vietnam's air defense network was fully integrated. Not only did the network possess thousands of radar- and optical-guided AAA and SAM sites, it also consisted of early-warning radars, intelligence-gathering efforts, and hundreds of ground-controlled interceptors. Thus while fewer American aircraft were lost to SAMs many more were lost in air-to-air combat during Linebacker.
Operation Linebacker II started off similarly to Linebacker I with regards to SEAD tactics but was remarkable for the introduction of B-52 Stratofortress bombers. However a combination of poor tactical employment and overconfidence on the part of Strategic Air Command resulted in the loss of a number of B-52s to SA-2 missiles, enough to force a rethink in how to counteract the enemy's air defenses. The latter part of Linebacker II finally saw a concerted effort made to suppress the entire North Vietnamese integrated air defense network and significantly reduced the losses suffered. Only one SA-2 missile for every sixty-eight fired resulted in a hit, the lowest ratio of the entire war. The SEAD tactics displayed at the end of Linebacker II, involving the combination of traditional understanding of SEAD with electronic warfare and command, control and communication countermeasures would lay the groundwork for future development.
The weapons most often associated with this mission are anti-radiation missiles (ARMs), which work by homing in on the radio emission sources like radar. These missiles are equipped with relatively small warheads, limiting collateral damage, but can easily destroy radar antenna and thus cripple an enemy's air defense system. Early examples of ARMs like the AGM-45 Shrike could be fooled by turning off the radar system and cease emitting radiation for the missile to track, however more recent ARMs including the American AGM-78 Standard, AGM-88 HARM and British ALARM are fitted with fire-control systems which "remember" where the source was and continue towards that location. Anti-radiation missiles proved particularly effective during the Vietnam War where, despite the small number carried relative to other munitions, they accounted for 46% of all SA-2 batteries destroyed. However, a weapon need not be designed specifically for SEAD missions to be used to damage or destroy a component of an air defense system. A Paveway LGB, for example, is not a SEAD-specific munition but, when used to destroy a radar antenna, it achieves the objective of suppression of enemy air defense. The relatively new American AGM-154 Joint Standoff Weapon is a valuable SEAD weapon due to its fairly long standoff range which allows the launching aircraft to avoid being threatened by all but the longest-range missiles, and its relatively large area of destruction against soft targets.
Possibly the most effective type of unguided ("dumb") weapon used during SEAD strikes are cluster bombs, because many SAM sites are dispersed over a fairly wide area, in order to increase the difficulty of inflicting serious damage on the battery, and the relative "softness" of the targets (missile launchers, exposed radars, etc.). The Mk-20 Rockeye II anti-armor cluster munition and the CBU-87 general-purpose cluster munition are often used against these fixed-location SAM sites, often for "clean-up" of a site whose radar or C&C facilities are first destroyed by a longer-range ARM or AGM.
Artillery is also used to conduct SEAD missions. After World War II the combined arms nature of warfare meant an increased role in ground forces performing SEAD missions in support of air operations. During the Cold War the American military developed a joint definition of SEAD responsibilities, with the Army responsible for all SEAD missions within the range of observable fire and the Air Force for all missions further away. The Soviet Union placed less emphasis on using artillery to conduct SEAD missions, although where possible artillery would be used to clear a path for attack helicopters. Because of their superior range rocket artillery such as MLRS are the ideal weapon for conducting SEAD operations.
Unmanned Aerial Vehicles (UAVs) play an increasingly vital role in conducting SEAD missions. Due to the dangerous nature of attacking air defenses, the use of UAVs can provide a more cost-effective and less risky method of conducting SEAD. This is especially true since the pilot is not directly at risk and so a commander may be more willing to sacrifice UAVs to accomplish the mission. The first UAVs used in the SEAD role occurred during the Vietnam War, when versions of the Lightning Bug were adapted to carry chaff and other electronic countermeasures. Modern examples of SEAD-specific UAVs include the IAI Harpy.
In 1978 a new F-4G 'Wild Weasel V' was developed which, along with the EF-111 Raven and EC-130H Compass Call, became part of the US Air Force's "triad" of electronic combat aircraft. Additional aircraft often part of SEAD missions included the E-3 Sentry, EC-130E Commando Solo and RC/EC-135. On the other hand, the Soviets did not treat SEAD as an independent air operation but as a tactical role to be performed as part of a larger mission, namely an overwhelming air assault against NATO. This role was not carried out by SEAD-specific aircraft but normal bombers and fighter aircraft, and was conducted against preplanned targets which had been identified by signals intelligence and other reconnaissance efforts prior to the attack rather than having aircraft seek out targets of opportunity. The closest the Soviets came to dedicated SEAD platforms were modified stand-off interceptors like the Mikoyan MiG-25BM and attack aircraft like the Sukhoi Su-24M carrying anti-radiation missiles. Other aircraft modified to carry ARMs included bombers such as the Tupolev Tu-16 and Tupolev Tu-22M.
As of 2014[update], the main United States Air Force (USAF) SEAD aircraft is the F-16CJ Fighting Falcon, while the US Navy replaced the EA-6B Prowler with the Boeing EA-18G Growler which fulfills the same role in the USAF following the EF-111A's retirement. The Air Force and Navy in recent decades have emphasized multirole aircraft over dedicated single-role designs with aircraft such as the F/A-18 Super Hornet navy multirole fighter and F-15E Strike Eagle medium strike fighter capable of carrying the AGM-88 HARM and fulfilling the same mission. The use of so-called "dumb planes" which lack the dedicated detection equipment of a true Wild Weasel is supposedly offset by their ability to carry a "smart missile" as well as perform a variety of missions besides SEAD with a lower operating cost. However there is concern that such platforms are less effective for this role because of the lack of specialized equipment, forcing them to employ expensive anti-radiation missiles in a less accurate and cost-effective manner. The advent of 5th-generation fighters has seen somewhat of a return to dedicated role aircraft; while the F-22 Raptor is capable of carrying ground ordinance, the aircraft's primary mission is air superiority unlike the more balanced profile of the F-16 and F/A-18. The upcoming F-35 Lightning II is intended to fulfill the ground strike mission profiles of most current multirole and strike fighter aircraft.
In European NATO air forces, the SEAD mission falls mostly to Royal Air Force Tornado GR4s, German Air Force Tornado Electronic Combat and Reconnaissance variant (ECR), and Aeronautica Militare (AMI) Tornado ECRs. The RAF Tornados rely on the aforementioned ALARM missile and the Italian/German Tornado ECRs employ the AGM-88 HARM missile. The Tornado ECR was designed from the outset as a SEAD platform and is unique in the European NATO air order of battle. Although several European NATO aircraft can carry SEAD weapons, few were designed for, or are specifically tasked with, the dangerous SEAD mission. All modern SEAD aircraft are modified to equip some level of electronic jamming equipment to make the job easier on the pilot.
- Boeing EA-18G Growler
- Lockheed Martin F-16CJ Fighting Falcon
- Northrop Grumman EA-6B Prowler
- Panavia Tornado ECR
- Shenyang J-8G
- Sukhoi Su-24MP
- Xian JH-7A
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- Davies, Peter, USAF McDonnel Douglas F-4 Phantom II, Osprey Publishing, 2013, p. 16
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- Bailey, p.77-78
- Chun, Clayton K. S., Aerospace Power in the Twenty-First Century: A Basic Primer, United States Air Force Academy, Colorado Springs, CO, p. 295-296
- Newcome, Laurence R., Unmanned Aviation: A Brief History of Unmanned Aerial Vehicles, American Institute of Aeronautics and Astornautics 2004, p. 83-86
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- Pace, Phillip E., Detecting and Classifying Low Probability of Intercept Radar, Artech House, 2009, p. 578-584
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- Navy Aviation: F/A-18E/F Will Provide Marginal Operational Improvement at High Cost, DIANE Publishing Company, 1997, pg. 93
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- Vectorsite Sukhoi Su-17 History
|Wikisource has several original texts related to: Audio recordings and transcripts with comments of actual Wild Weasel combat missions over Vietnam.|