Suppression of enemy air defenses (SEAD ), also known in the United States as "Wild Weasel" and (initially) "Iron Hand" operations, are military actions to suppress enemy surface-based air defenses, including surface-to-air missiles (SAMs), anti-aircraft artillery (AAA), and related systems such as early-warning radar and command, control and communication functions.

Suppression can be accomplished by physically destroying the systems or by disrupting and deceiving them through electronic warfare. In modern warfare, SEAD missions can constitute up to 30% of sorties launched in the first week of combat and continue at a reduced rate through the rest of a campaign.Tucker, Spencer C. (Editor), The Encyclopedia of Middle East Wars: The United States in the Persian Gulf, Afghanistan, and Iraq Conflicts, ABC-CLIO, 2010, pp. 61–62. One-quarter of American combat sorties in recent conflicts have been SEAD missions.Bolkcom, Christopher. "Military Suppression of Enemy Air Defenses (SEAD): Assessing Future Needs." CRS Report for Congress, 2005, p. 5. They are generally associated with aircraft, but may be performed using any means, including ground forces.

In some contexts, destruction of enemy air defenses (DEAD) refers to physical destruction of air defense targets, while SEAD applies to sorties which discourage enemy use of air-defense radar assets out of fear of placing the assets in jeopardy.

Primitive operations akin to SEAD emerged during the Second World War: efforts to degrade enemy ground radar stations. The Vietnam War saw the first SEAD missions performed by dedicated aircraft. Other early conflicts with SEAD efforts included the 1982 Falklands War, over Port Stanley, and the 1982 Lebanon War, in the Beqaa Valley. The 1990s saw extensive use of SEAD, particularly during the Gulf War. During the Kosovo War in 1999, air defenses proved less vulnerable and more effective with the downing of an F-117A Nighthawk marking the first combat loss of a stealth aircraft. In the Iraq War of the 2000s, coalition aircraft targeted Iraqi SAMs during the opening phase of the conflict, yet aerial strikes were usually performed from stand-off distances to avoid these defenses, and low-level flight was avoided. In the Russo-Ukrainian War, while many Ukrainian air defense facilities were reportedly destroyed or damaged in the first days of full-scale invasion by Russian air strikes, Russia may not have been able to gain aerial superiority; it has been alleged that Ukrainian mid-range SAM sites have forced planes to fly low, but this makes them vulnerable to shoulder-launched surface-to-air missiles.

History

Pre-Vietnam War Before the Vietnam War, SEAD was an undefined mission: although attempts to destroy enemy air defense sites were undertaken, they were done so by individual aircraft against specific targets or operations, not as part of an overall strategy or doctrine of defense suppression.Brungess, James, Setting the Context – Suppression of Enemy Air Defenses and Joint War Fighting in an Uncertain World, Air University Press, June 1994, p. 7. Near the end of the Second World War, US Navy pilots developed a doctrine that could be considered the first example of SEAD. When attacking enemy warships, US Navy fighters would attack enemy warships with machine guns and rockets to distract and or kill the enemy anti aircraft gunners while the torpedo and dive bombers could move in and more accurately target the ship. While crude, these tactics were frequently effective for their time.Brungess, p. 55.

World War II During the Battle of Britain, the German Luftwaffe attempted to destroy Great Britain's Chain Home radar stations in order to degrade the British 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.Hough, Richard Alexander and Denis Richards, The Battle of Britain: The Greatest Air Battle of World War II, W. W. Norton & Company, Inc., 1989, pp. 138–143, 220. 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 were cut in half but losses to flak increased tenfold.Hewitt, William A., Planting the Seeds of SEAD: The Wild Weasel in Vietnam, School of Advanced Airpower Studies, Air University, May 1992, p. 5.

Understanding the importance of Germany's radar sites, the Allies directed attacks against these installations and introduced new technology to counteract the effects of radar-directed AAA, including CARPET (US) and WINDOW (UK). A change in tactics saw bomber formations flying 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 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.Hewitt, pp. 6–9. 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 of twenty-two minutes at some one hundred targets, the mission was unsuccessful due to inaccurate targeting data and insufficient firepower.Bailey, Johnathan B. A., Field Artillery and Firepower, Naval Institute Press, 2004, p. 76.

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.Norman Polmar, Thomas B. Allen, World War II: the Encyclopedia of the War Years, 1941–1945, Courier Dover Publications, 2012, pp. 274–275 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.Cleaver, Thomas McKelvey, Air Combat Annals, Pacifica Military History, 2011.

Korean War While there were some technological changes between World War II and the Korean War, many of the tactics for dealing with enemy air defenses remained the same. 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.Olsen, John Andreas, A History of Air Warfare, Potomac Books, Inc., 2010, p. 89. The terrain and weather of the Korean Peninsula also contributed to the dangers associated with ground-attack missions. Nevertheless, 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.Olsen, p. 92.

As the war progressed, the Communists developed a highly centralized integrated air defense network, incorporating early-warning radars, ground-controlled interception (GCI) 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, but the North Korean Air Force had been largely destroyed early in the war and the Chinese Air Force was almost exclusively focused on the mission of air superiority rather than attacking UNC ground forces.Olsen, pp. 98–100.

Vietnam War

The Vietnam War saw the evolution of what would become known as SEAD over the course of the conflict. At 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 system (IADS) 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 Sabres 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.Brungess, pp. 4–5 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. This also put the aircraft well within range of AAA, which would account for nearly 85% of all American aircraft losses during Rolling Thunder.Brungess, pp. 6–8.

Eventually new SEAD-dedicated aircraft were introduced, 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 anti-radiation missiles (ARMs). These fighter-bombers became very adept at tracking down and destroying ground-based air defense weapons, such that it became common for a vast majority of NVA SAM operators to turn off their radars whenever an F-105G was spotted. While this prevented the SAM from physically being destroyed, it essentially accomplished the same mission of suppressing air defenses 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.Davies, Peter, F-105 Wild Weasel vs SA-2 'Guideline' SAM, Osprey Publishing, 2011, p. 71. In spite of these changes, SEAD remained a primarily tactical function throughout Rolling Thunder, with American leadership either unaware or unappreciative of North Vietnam's IADS.