An analysis of NATO electronic warfare operations over the Balkans

It is more than 20 years since NATO did battle in Balkan skies. Operations Deliberate Force and Allied Force witnessed the largest air defence suppression efforts Europe had seen since World War 2. 

The international community’s patience with the Republika Srpska finally snapped on 30 August 1995. Civil war had raged in the disintegrating Yugoslavia since April 1992, and news bulletins regularly reported atrocities Europeans believed were consigned to the horrors of World War 2. 

Bosnia and Herzegovina became bywords for ethnic cleansing and genocide, and ‘the straw that broke the camel’s back’ was the second bloody attack by Bosnian Serb forces on a marketplace in the Bosnian capital Sarajevo on 28 August 1995, killing 43 civilians and wounding 75. To stop further attacks, NATO launched Operation Deliberate Force (ODF) against the Bosnian Serb army.

NATO’s air armada faced the Ground-Based Air Defence (GBAD) units of the Republika Srpska Air Force and Air Defence Force (RSAFADF). The US Central Intelligence Agency (CIA) had made a preliminary assessment of Yugoslav military capabilities in June 1993. The CIA concluded that the RSAFADF possessed between 38 to 40 Surface-to-Air Missile (SAM) launchers. 

These included S-75 Dvina (NATO reporting name SA-2 Guideline) high-altitude SAM systems, S-125 Neva/Pechora (SA-3 Goa) medium-altitude systems, and short-range, medium-altitude systems including the 2K12 Kub (SA-6 Gainful) and 9K31 (SA-9 Gaskin). Lower altitudes were protected by 9K35 Strela-10 (SA-13 Gopher) Short-Range Air Defence (SHORAD) launchers, in addition to an unknown number of Man-Portable Air Defence Systems (MANPADS). 

The CIA assessment posited that the RSAFADF GBAD assets were probably tied into the wider Yugoslav Integrated Air Defence System (IADS). The report concluded that the break-up of Yugoslavia had a profound impact on the ability of Serbia and Montenegro to field adequate GBADs, noting “The break-up of the former Yugoslavia…resulted in the loss of facilities and up to 50 per cent of the technically trained personnel”.  

OPERATION DELIBERATE FORCE 
ODF saw the deployment of 600 NATO aircraft to support an air operation of 41 days and, of those, 54 platforms were dedicated Suppression of Enemy Air Defence (SEAD) and Signals Intelligence (SIGINT) assets. Similar platforms were deployed to those of Operation Desert Storm waged four years earlier. 

The USAF deployed Lockheed EC-130H Compass Call and General Dynamics EF-111A Raven aircraft for electronic attack, and these engaged hostile radio communications and ground-based radar respectively. Radar kinetic attack was performed by USAF General Dynamics F-16CJ Viper Weasels and McDonnell F-4G Wild Weasels, and these were supported by German Luftwaffe Tornado-ECRs. All these aircraft deployed Raytheon AGM-88B/C HARM (High Speed Anti-Radiation Missiles). 

AGM-88s were also employed by US Navy and Marine Corps Grumman EA-6B Prowlers which could also perform electronic attack. SIGINT platforms comprised French Armée de l’Air DC-8 Sarigue, Luftwaffe Breguet ATL-2 Atlantique, and Royal Air Force Nimrod-R1s. The USAF, meanwhile, deployed USAF RC-135U Combat Sent Electronic Intelligence (ELINT) aircraft to gather strategic and operational-level ELINT on Bosnian-Serb radars.

The SEAD dimension to ODF began several months prior. NATO aircraft had repeatedly been targeted by the Bosnian Serb IADS before the operation began, resulting in United Nations and North Atlantic Council approval for the drafting of a SEAD plan covering the engagement of IADS sites within Bosnia-Herzegovina, the majority of which were in Bosnian-Serb territory. 

The SEAD plan was codenamed Operation Deadeye and was to provide NATO aircraft freedom of movement in enforcing the no-fly zone above Bosnia-Herzegovina which was enacted via Operation Deny Flight commencing on 12 April 1993. The SEAD effort was geographically subdivided into two zones of action, Deadeye Southeast, and Deadeye Northwest. 

Initially SEAD efforts would focus on Bosnian-Serb early warning and ground-based air surveillance radar, and SAM targets in the southwest, but would expand to include the northwest as and when required.  

By late August 1995, NATO estimated it would face Bosnian-Serb GBAD which included seven S-75, six 2K12 and 12 9K31 batteries, and operations commenced on 30 August including SEAD missions from the outset. A total of 35 aimpoints associated with the Bosnian-Serb IADS located in the Southeast sector were struck. 

By 7 September, the SEAD effort had been deemed successful, but continued suppression was required due to redundancy built into the IADS giving a measure of survivability. Furthermore, unlike the Iraqis four years before, the Bosnian-Serbs had understood the tactical bonus in conserving their IADS resources. 

For example, an awareness of US and NATO SEAD capabilities encouraged air defenders to keep their target acquisition radars switched off, thus hampering the ability of the AGM-88B/Cs to engage them. On the one hand this denied the Bosnian-Serbs the ability to employ their IADS to its greatest operational effect. On the other, it ensured NATO was never able to attrit the IADS to such a point where it could no longer influence the wider air battle as had been done in Iraq. 

Therefore, the IADS required continued attacks and suppression efforts to ensure it remained bowed, if not out. This same tactic was employed by Serbia with aplomb four years later during Operation Allied Force. 

SEAD efforts were confined to the southeast zone into early September 1995, but on 9 September operations were widened to include Bosnian-Serb IADS targets in the northwest zone. Despite conserving their IADS resources, NATO’s SEAD efforts during ODF did have a positive effect, helping keep alliance losses to a minimum. 

During ODF NATO suffered just one combat loss, a French Dassault Mirage-2000K2 fighter. The crew were captured but released in December 1995. 

OPERATION ALLIED FORCE 
Four years after ODF, NATO was once again embroiled in an air war over the Balkans, with Operation Allied Force (OAF) opening on 26 March 1999. Its goal was to end the ethnic cleansing of the Kosovar Albanian population in the province of Kosovo. 

Despite Yugoslav air defences being badly degraded following the break-up of the country, they could still challenge NATO’s mastery of the skies. The final report to the US Congress examining OAF spoke of aircrews witnessing higher SAM launch-rates than that witnessed during Desert Storm. That said, the success rate per-launch was notably less than that seen over Iraq. 

Serbian GBAD operated in a disconnected and fleeting fashion, seemingly counter-intuitive to the philosophy underpinning the IADS principles which emphasise such defences operating in a closely connected and coordinated manner. Serbian GBAD attempted to engage NATO aircraft as and when possible, exploiting targets of opportunity. Moreover, Serbian air defenders were adept at using SHORAD, MANPADS, and anti-aircraft artillery (AAA) to challenge NATO airpower and, as a result, NATO flew at altitudes eclipsing the reach of such weapons.  

OAF-deployed SEAD assets included US Navy and US Marine Corps EA-6Bs, and USAF F-16CJs and EC-130Hs.  Other aircraft supporting the air defence suppression effort included USAF RC-135W Rivet Joint and US Navy EP-3E SIGINT gatherers. Allied SEAD capabilities included 18 Italian Aeronautica Militaire Panavia Tornado-ECRs and eight similar aircraft from the Luftwaffe. Allied SIGINT gathering aircraft included a single Luftwaffe ATL-2 and a French C-160G. 

The concept of operations for the SEAD element of OAF included kinetic attack, principally using AGM-88B/C missiles, and electronic attack, principally executed by the EA-6B. Air defence suppression was unable to render the Serbian IADS incapable of resistance, and the loss of two aircraft – one USAF Lockheed F-117A Nighthawk and an F-16C – was testament to this. 

That said, the IADS was unable to meaningfully challenge NATO airpower. As the official report noted, “NATO succeeded because we maintained pressure on (the Serbian) defences, forcing the Serbs to keep their systems hidden under most circumstances and to use defensive tactics that limited their systems’ effectiveness”.  However, as the NATO report concedes, forcing the Serbians to hide elements of their IADS was a double-edged sword, as the alliance, “had difficulty targeting the Serb defensive systems”. 

Dispersion of the Serbian IADS began before OAF commenced, but Serbian air defenders were quick to exploit targets of opportunity. This was dramatically illustrated on 27 March when Serbian air defenders shot down the F-117A. 

Much had been made of the supposed invulnerability of this aircraft to radar, but the Nighthawk’s low Radar Cross Section (RCS) was not optimised for the relatively low frequency ground-based air surveillance radars used by the Serbians. Combined with the use of predictable medium altitude ingress and egress routes, this led to the F-117A’s demise.

The loss of the jet handed the Serbian armed forces a major propaganda victory, while Both Russian and Chinese aeronautical engineers are thought to have enjoyed access to the wreckage. This would have been an advantage to both countries’ RCS research. 

One remarkable aspect of OAF is that, despite Serbian tactics, NATO aircraft faced more danger from radar-guided SAMs than US and coalition combat aircraft over Iraq. The official report notes that 21,000 combat sorties were flown during OAF versus 69,000 flown during Desert Storm. But Iraqi and Serbian air defenders launched similar numbers of radar-guided SAMs during these respective conflicts. 

OAF aircrews thus faced a SAM launch rate three times that encountered by their counterparts over Iraq. But OAF aircrews were six times more likely to survive than during Desert Storm. 

Why was this? Quite simply, Serbian tactics were ineffective, with SAMs often fired with little or no guidance. This avoided air defenders having to use their radars which may have earned them an AGM-88 visit for their trouble. Moreover, as the report noted, “by conserving their systems and attempting to down NATO aircraft as targets of opportunity, they gave up many of the advantages of a connected and continuously operating system in order to achieve tactical surprise”. 

In effect, the Serb military had an IADS in name only. Its fragmentation and concealment meant it could no longer operate in a coordinated manner, thus handing a significant advantage to NATO. 

CONCLUSIONS
Operations Deliberate and Allied Force were the largest air defence suppression efforts Europe had seen since World War 2. 

Half a century earlier, RAF Bomber Command had led a similarly impressive effort against the Luftwaffe’s IADS but, unlike NATO, this largely eschewed a kinetic effort. Instead, Bomber Command relied on electronic attack to jam Luftwaffe radar, radio communications, and radio navigation systems. 

Like Desert Storm, ODF and OAF reaffirmed the importance of a coordinated and intense air defence suppression effort. SEAD was and is an indispensable part of an air campaign’s Offensive Counter Air (OCA) component. Targeting hostile air forces in the air and on the ground to win air superiority and air supremacy was vital from the outset. 

Since ODF and OAF, there are understandable concerns in some quarters of the NATO airpower community that SEAD lessons and capabilities may have atrophied during the alliance’s long engagement in Afghanistan. The Afghan theatre had largely uncontested airspace, and the main threat existed from small arms fire and MANPADS at low altitude. There was no IADS with which the alliance had to contend. 

NATO’s Operation Unified Protector commenced in March 2011 to help protect Libyan civilians from Colonel Muammar Gaddafi’s forces during the Libyan civil war. The Libyan armed forces possessed an IADS, but this was engaged and degraded to the point of ineffectiveness by NATO air defence suppression assets, thus helping to dispel concerns that NATO air defence suppression skills were rusty. 

In Iraq, the Balkans, and over Libya, US, allied, and NATO forces encountered and defeated ageing Soviet-vintage GBAD systems. But matters may be different the next time Western powers battle an IADS. 

Russia has learned the correct lessons and has reasoned that ensuring the cost for any aggressor attacking her territory must be as high as possible. This has resulted in the development of new state-of-the-art and highly capable SAM systems such as the Almaz-Antey S-400 (SA-21 Growler) which is yet to be encountered in combat by US and allied air forces. 

For all intents and purposes, the S-400 remains a largely unknown quantity. Sources have told the author that the ELINT gleaned from S-400s deployed by Russia to Syria is minimal at best. But one can reliably suppose that it is a significant leap forward in capability compared to those systems encountered over Serbia, Iraq, and Libya. 

NATO’s air defence suppression efforts in the Balkans were successful. While it is useful to learn lessons from history, one must not become its slave. The next time NATO goes to war, there is every chance that its opponent might possess an IADS far superior to those the alliance has encountered before. It must be ready. 

This article appeared in the July-August 2021 issue of ADBR.