Military Suppression of Enemy Air Defenses (SEAD): Assessing Future Needs
CRS Report for Congress
Military Suppression of Enemy Air Defenses
(SEAD): Assessing Future Needs
Specialist in National Defense
Foreign Affairs, Defense, and Trade Division
Suppressing enemy air defenses (SEAD) has been a central element of projecting
military air power for over 50 years. However, several developments suggest that this
mission is of growing importance to the Department of Defense (DOD). Some say that
the emergence of new technologies and air defenses will increasingly challenge U.S.
SEAD efforts. Making budgetary judgments on SEAD programs and processes requires
the assessment of complex factors. This report will be updated.
Suppression of enemy air defenses (SEAD) is defined by the Department of Defense
(DOD) as “That activity that neutralizes, destroys, or temporarily degrades surface-based
enemy air defenses by destructive and/or disruptive means.”1 By this definition, many
military platforms, munitions, and processes contribute to SEAD, including
reconnaissance and surveillance, stand-off jamming, employment of air-to-surface
munitions, and electronic and infrared (IR) countermeasures.2
A variety of weapons platforms and munitions can and have been used to attack
enemy air defenses, including long range bombers, helicopters, surface-to-surface
missiles, precision guided munitions (PGMs), rockets, and “dumb bombs.” However,
some combat aircraft have been designed or modified to increase their effectiveness
against enemy air defenses and are typically thought of as SEAD assets. These include
the F-16, EA-6B, F/A-18, F-15E, and recently F-22A. These aircraft carry a number of
munitions useful against surface-to-air missiles (SAMs). Some carry the AGM-88 High
Speed Anti Radiation Missile (HARM) which is designed to lock-on to and destroy the
ground-based radars used by some SAMs and anti-aircraft artillery (AAA). Also, the
HARM Targeting System (HTS) and the Tactical Electronic Reconnaissance Processing
1 Joint Publication 1-02. DoD Dictionary of Military and Associated Terms, Apr. 12, 2001.
2 For discussion of stand-off jamming and electronic warfare, see CRS Report RL30639.
Congressional Research Service ˜ The Library of Congress
and Evaluation System (TERPES), improve the ability of the F-16CJ and Marine Corps
EA-6B Prowlers to target enemy air defense radars.
Suppressing enemy air defenses has always been an important means of protecting
U.S. aircraft, and enabling effective air operations. However, SEAD may be of growing
importance to DOD and Congress for at least three reasons.
!While combat aircraft have played an important role in most U.S.
conflicts since World War I, the last several conflicts (Bosnia in 1995,
Kosovo in 1999, Iraq 1996-present, and Afghanistan in 2001) have
emphasized the use of airpower.
!There appear to be very few countries capable of seriously challenging
U.S. air forces in air-to-air combat. Since Operation Desert Storm, 100
percent of all U.S. combat aircraft losses have been due to enemy air
defenses. No U.S. aircraft has been lost to an enemy aircraft since 1991.
Most countries will challenge U.S. airpower primarily with surface-based
!DOD finds some air defenses difficult to suppress or destroy. Many
analysts say that emerging air defense technologies and tactics will prove
more threatening and more difficult to counter than current systems.
Issues of Concern
The Pentagon frequently expresses concern over several interrelated developments
in enemy air defenses: the emergence and proliferation of a new generation of Russian
SAMs, and the application of new technologies, either in conjunction with these or with
other air defense elements. Shoulder-fired missiles continue to pose a problem for today’s
SEAD forces. Observers are also concerned about the effect of strict rules of engagement
on SEAD effectiveness.
Russian SA-10 and SA-12 SAMs have been operational since the 1980s, but
currently are in the inventory or possession of only a handful of countries (e.g., Russia,
China, Cyprus, The Czech Republic, and Germany).4 These “double digit” SAMs are a
concern for military planners due to their mobility, long range, high altitude, advanced
missile guidance, and sensitive radars. The Russian SA-20, still under development, has
been likened to the U.S. Patriot PAC-2 missile, but with an even longer range and a radar
capable of detecting stealthy aircraft. Military planners are concerned that a country with
only a handful of these SAMs could effectively challenge U.S. military air operations by
threatening aircraft and disrupting operations from great distances.
3 Historically, the percentage of U.S. combat losses due to aerial combat has steadily declined and
the percentage of losses due to enemy air defenses has steadily risen. In World War II, U.S. air
combat losses were split almost evenly between aerial combat (46%) and air defenses (54%). By
the Korean and Vietnam wars however, combat losses due to enemy air defenses had risen to
approximately 90% and aerial combat losses had dropped to approximately 10 percent.
4 World Missiles Briefing, Teal Group, Inc., Feb. 2005. India, Iran, Syria and Vietnam are known
to have negotiated with Russia for these systems, but acquisition has not been confirmed.
A variety of new technologies and military systems could exacerbate the “double
digit” SAM challenge. First, commercial information and communications technologies
are enabling adversaries to better network the elements of their air defense systems. This
allows them to disperse radars, SAM launchers and other associated platforms throughout
the battlespace, and to share targeting information between launchers. This, in turn,
suggests that radars may be used less frequently and for shorter periods of time,
complicating U.S. SEAD efforts. Second, terminal defenses are being marketed by a
number of international defense companies. These radar-guided Gatling guns are
designed to protect “double digit” SAMs or other high value air defense assets by
shooting 3,000 to 4,500 rounds per minute into the sky. These systems could prove quite
effective in shooting down HARM or other missiles aimed at enemy air defenses. Third,
Russia and other countries have developed and are selling GPS jammers. Over varying
distances, these low-watt jammers degrade or totally disrupt the GPS guidance signals
used by many U.S. PGMs to augment inertial guidance systems, reducing their accuracy.
U.S. military planners must also grapple with today’s pernicious air defense threats,
such as shoulder-fired missiles. Unlike “double digit” SAMs, MANPADs (eg. the U.S.
Stinger, Russian SA-7, and French Mistral) are widely proliferated, and found in the
inventories of scores of countries. These missiles are difficult to suppress due to their
small size, high mobility and IR guidance. Unlike radar guidance, IR guidance — which
MANPADs tend to use — does not emit energy that U.S. self-defense systems can detect.
Thus, the launch of an IR-guided missile often comes as a surprise to the targeted aircraft,
reducing the time for evasive maneuvers or deployment of self protection
countermeasures. This increases MANPADs effectiveness. IR guided SAMs were the
primary source of air combat losses in Operation Desert Storm,5 and since 1973, nearly
half of all air losses in combat have been attributed to IR-guided SAMs, many of them
launched from MANPADs. Others estimate that MANPADs caused 90% of worldwide
combat aircraft losses from 1984-2001.6
Shoulder-fired missiles also pose a terrorist threat to civilian aircraft. RAND
estimates that at least 20 and as many as 40 civilian airliners were shot down by terrorists
using MANPADs between 1975 and 1992.7 (CRS estimates six of these aircraft were
actually airliners, the others were smaller than most commercial aircraft.)8 The threat to
civilian airliners posed by terrorists with shoulder-fired missiles appears to be an issue of
increasing congressional concern. At least three bills introduced during the FY2005
budget cycle addressed methods for mitigating the threat of shoulder-fired missiles to
Rules of engagement (ROE) are designed by military planners to reduce the
likelihood of fratricide (shooting down friendly aircraft), to minimize unintended civilian
casualties, and in some cases, for political feasibility (e.g., operating in ways palatable to
5 Steven Zaloga, “The Evolving SAM Threat: Kosovo and Beyond,” Journal of Electronic
Defense, May 2000.
6 Michael Puttre, “Facing the Shoulder-Fired Threat,” Journal of Electronic Defense, Apr. 2001.
7 Marvin B. Shaffer, Concerns about Terrorists with Manportable SAMs (RAND, 1993), p. 3.
8 CRS Report RL31741, Homeland Security: Protecting Airliners from Terrorist Missiles.
9 Ibid., p 20.
coalition partners). Some have asserted that ROE in recent conflicts have been
“draconian” and tied the hands of SEAD pilots; reducing their effectiveness.10 DOD may
seek congressional support for more lenient ROE in future wars.
Assessing Future SEAD Needs
There are many factors that can be weighed, when attempting to measure the success
of DOD SEAD efforts, and determining what future needs (e.g., new aircraft, upgrades
to self-protection capabilities, better munitions) may be. DOD has had considerable
experience suppressing enemy air defenses over the last 50 years. A survey of this
experience provides some insight into SEAD success and challenges, and helps provide
a context in which Congressional oversight decisions can be made. The following section
describes three “measures of effectiveness” (MOEs) that can be used to focus
Congressional inquiry into future SEAD needs.
MOE 1: Combat Attrition. The first area that merits examination is combat
attrition. How many U.S. combat aircraft have been shot down in recent conflicts? How
many have been shot down by ground-based air defenses? Because SEAD missions are
designed ultimately to protect U.S. aircraft, combat attrition provides some insight into
the effectiveness of SEAD efforts. As indicated in Table 1 below, from World War II to
the present, the loss of U.S. combat aircraft has steadily declined, both in absolute terms,
and relative to the number of combat sorties flown. While these numbers do not prove
that SEAD is solely responsible for this very favorable trend, it is clear that SEAD is an
important contributor to aircraft survivability.
Table 1. Estimates of Combat Aircraft Losses
ConflictCombat SortiesTotal CombatLossesaAttrition Rate
World War IIb2,498,28319,0300.76%
Koreac 591,693 1,253 0.2%
Vietnamd (AF data only)219,4071,4370.65%
Desert Storm (Iraq)e68,150330.04%
Bos n i a f 30,000 3 0.01%
Kosovog 21,111 2 0.009%
Other losses, either due to pilot error, accident, or unknown enemy action not included.b
Army Air Force Statistical Digest: World War II. Prepared by the Office of Statistical Control. December
1945. p220, Table IIB. Naval Aviation Combat Statistics: World War II. Air Branch. Office of Naval
Intelligence, Office of the Chief of Naval Operations. Washington, DC. 17 June 1946. p. 51-59.
10 Benjamin Lambeth, NATO’s Air War for Kosovo (RAND, 2001), p. 142.
Greene, Terrell. “Surviving Modern Air Defenses.” Aerospace America. American Institute of
Aeronautics and Astronautics. August 1986. p.14.c
Robert Futrell, The United States Air Force In Korea. Office of Air Force History, US Air Force.
Washington, 1983, pp. 689-692.d
Wayne Thompson, To Hanoi and Back: The USAF and North Vietnam, 1966-1973, Air Force History and
Museums Program, USAF, 2000, pp. 304, 311.e
Gulf War Air Power Survey, vol. v.: Statistical Compendium and Chronology. Washington, 1993, pp. 232,
641. US and coalition partners.f
John Tirpak, The NATO Way of War. Air Force Magazine. December 1999. p. 24. Figures represent
coalition combat sorties and losses.g
Correspondence from Lt.Gen. C.W. Fulford, (USMC) Director, Joint Staff to Mr. Daniel Mulhollan,
Director, Congressional Research Service. October 19, 1999.h
Gen Walter Buchanan, Air Force Current Operations. Briefing to Congressional Air Power Caucus.
Bolling AFB. Mar. 12, 2001. According to USCENTCOM Press Release (8/10/01) Iraq has
conducted over 1,000 attacks against U.S. and Allied aircraft since December 1998.I
Operation Iraqi Freedom — By the Numbers. Assessment and Analysis Division. USCENTAF Lt. Gen.
Michael Moseley, Commander, Apr. 30, 2003.
MOE 2: Effort Expended. Another factor that can be considered when assessing
U.S. SEAD capabilities is the amount of effort that is expended to protect U.S. aircraft.
How onerous a mission is SEAD? As Table 2 below suggests, twenty-to-thirty percent of
all combat sorties in recent conflicts were devoted to SEAD, while historically, this ratio
is much lower. While this increase in SEAD sorties could be attributable to a number of
factors, it appears that SEAD is a growing mission area.
Table 2. Estimates of SEAD sorties and Total Combat Sorties
ConflictCombat SortiesSEAD Sorties%
V i etnama 219,407 11,389 5.2
Desert Storm (Iraq)b68,1504,3266.3
Bos n i a c 2,451 785 32.0
Kosovod 21,111 4,538 21.5
Notes : a
Conversation with Dr. Wayne Thompson, Center for Air Force History, Bolling AFB, Aug. 9, 2001.
Figure includes 8,669 F-105 Wild Weasel sorties, and 2,720 “Flack Suppression sorties. Figures
include USAF sorties only. Does not include 24,278 EB-66 or 11,732 misc. EW sorties.b
Gulf War Air Power Survey. vol. v: Statistical Compendium and Chronology (Washington, 1993), p. 232-
233. Figures include coalition partners. Does not include 2,918 EW sorties.c
Deliberate Force: A Case Study in Effective Air Campaigning. Final Report of the Air University Balkans
Air Campaign Study. Edited by Col. Robert C. Owen, USAF, Air University Press, Maxwell Air
Force Base, Alabama, Jan. 2000, p. 334.d
Fulford, Mulhollan correspondence, op. cit.e
Maj. Gen. Walter Buchanan, Air Force Current Operations, Briefing to Congressional Air Power Caucus,
Bolling AFB, Mar. 12, 2001.
MOE 3: Efficiency. By some measures, U.S. SEAD efforts have been effective.
However, other observations suggest that efficiency could be improved. For example, one
MOE pertains to the destruction of enemy air defenses (DEAD). While suppressing
enemy air defenses through electronic warfare (EW) or intimidation can effectively
protect U.S. aircraft, the effect is ephemeral. Destroying enemy air defenses is generally
preferred to suppressing them, because of the enduring effect that destruction has on
military capabilities. As Table 3 suggests, U.S. air forces have had mixed results in recent
conflicts destroying enemy air defenses. In some cases, such as in Iraq, U.S. destructive
SEAD efforts have been somewhat successful. In other cases, such as Kosovo — where
the Serbs employed a variety of challenging tactics — efforts were less successful.
Table 3. Destructive SEAD: Some Estimated Results
Desert Storma35 of 120 fixed SAM batteries destroyed
Bosniab52 of 70 air defense targets destroyed
Kosovoc3 of 25 SA-6 batteries destroyed, 10 of 41 SAM radars destroyed
N./S. Watchd33 of 35 air defense targets damaged, but many rebuilt and improved
Gulf War Air Power Survey, vol. v., op. cit. , p. 19.b
Deliberate Force Case Study, op. cit., p. 342. c
Benjamin Lambeth, “Kosovo and the Continuing SEAD Challenge,” Aerospace Power Journal, Summer
2002, and interview with personnel involved in Operation Allied Force.d
Iraq Improves in Face of Bombs, New York Times on the Web, Aug. 30, 2001.
Another measure of efficiency pertains to tactics. One SEAD tactic to fire numerous
HARM missiles preemptively — that is, in the direction of a SAM that is suspected to
exist, but which hasn’t turned on its radar. Thirty three of 56 HARMs used in Operation
Deliberate Force were fired preemptively.11 Over 1,000 HARMs in Operation Allied
Force were fired at only a handful of SAMs, suggesting many preemptive shots.12 While
using HARMs in this way may effectively deter adversaries from shooting at U.S. aircraft,
it also poses two problem areas. First, preemptive HARM use can be expensive since
HARMs cost approximately $250,000 per missile. Second, preemptively fired HARMs
present a fratricide risk. If there are no enemy radar emissions for the HARM to guide on,
the missile could lock-on to friendly emissions and destroy the wrong target. At least six
HARMs shot during Kosovo ended up by accident in Bulgaria.13 While launching
HARMs preemptively may be effective and necessary, it not efficient. The Navy’s
Advanced Anti-Radiation Guided Missile (AARGM) program, may reduce the need for
or the potentially negative effects of preemptive missile launches ($75M requested in
FY2006). The AARGM program is pursuing a number of improvements to HARM,
including adding a radar that can detect enemy radars after they have turned off, and
hardware and software improvements that limit the areas in which the missile can fly
when searching for a target.
11 Deliberate Force Case Study, op. cit., p. 315.
12 Rep. Randy “Duke” Cunningham, Suppression of Enemy Air Defenses: Improvements Needed,
EW Working Group Issue Brief #7.
13 Gert Kromhout, “From SEAD to DEAD,” Military Technology, Apr. 2001.