Next Generation Counter-air
By John Conway
History matters. While doctrine, tactics and plans tell us how to fight in the future, history teaches us what went wrong in the past.
In Vietnam, air power was used in a gradual approach to apply pressure against the political leadership of North Vietnam. It failed. US Air Force historian Richard Hallion wrote after the Gulf War that, ‘…air power was misused in Vietnam, with that misuse often clouding results attributed to the limits of air power when they really stemmed from limits on air power.’
But history can also teach us how to succeed by reminding us how we failed and what we did right, and some things did go right in Vietnam. According to Hallion, the December 1972 Linebacker II offensive shattered North Vietnam’s air defence network and compelled the North Vietnamese government to the negotiating table. It also showed how the integration of combat power and the synchronisation of intelligence and tactics could lead to battlefield success. While almost 50 years have passed since Linebacker II, the lessons from the air war over North Vietnam are still relevant
At the peak of Operation Rolling Thunder in 1967, the US lost 366 fixed-wing combat aircraft. North Vietnam seized the initiative in the air war by exploiting weaknesses in the way the US had conceived, organised, and prepared for the campaign. The US was not prepared to fight a limited conventional war from the outset – the driving force design of Cold War politics had caught the USAF and US Navy wrong-footed.
In the quest for air superiority the US applied a Cold War defensive counter-air (DCA) mindset to Vietnam. But instead of the Soviet bomber stream, US aviators faced intense air-to-air combat against small, agile fighters. Meanwhile the US offensive strike capability was dominated by aircraft and tactics that had been optimised for nuclear weapons delivery over the vast open spaces of the Soviet Union, not against tightly integrated air defences in mountainous jungle terrain.
Back in the continental US national intelligence systems were compartmentalised, controlled, and highly adversarial. Intelligence sharing was hamstrung by administrative and technological issues and cultural factors.
The ‘Green Door Syndrome’ referred to the practice of hiding valuable intelligence feeds behind partitions. While this was intended to prevent exposing sensitive Cold War signals intelligence (SIGINT) capabilities and the extent to which the US was conducting its wider collection operations in South-East Asia (SEA), it also meant actionable intelligence took far too long to reach key decision-makers, including aircrew fighting for their survival.
Despite pockets of tactical brilliance, there was a lack of operational synchronisation between the physical and information domains, and it was left to innovators at the tactical level to solve problems like the suppression of enemy air defence (SEAD). For example, ‘Project Wild Weasel’ – the development of a dedicated surface-to-air missile (SAM) detection and suppression aircraft – and the Iron Hand missions during Rolling Thunder relied on the bravery and ingenuity of US aviators.
What can the history of the Vietnam Air War teach us today? The integration of intelligence into counter-air operations provides an advantage in air combat. The US and North Vietnam both turned this into a decision-making advantage, providing an opportunity to get into the mind of an adversary command structure to understand intent, shape behaviour, and avoid strategic surprise.
Declassified Central Intelligence Agency (CIA) Directorate of Intelligence memoranda from 1968 and National Security Agency (NSA) Cryptologic Quarterly publications from 1975 provide an alternative insight into the Vietnam War. These documents look beyond the platform-vs-platform engagements and bombing missions, and allow us to explore how to gain an information advantage.
Air Superiority Meets Air Deniability
Military and political decision-makers back in the US imposed complex, highly restrictive rules of engagement on the USAF and US Navy. The intent was to bring North Vietnam to the negotiating table through a managed escalation, while avoiding wider confrontation with the Soviet Union and People’s Republic of China (PRC).
But the lack of a clear US strategy – the use of military force to achieve political goals – gave the North Vietnamese government enough time to mobilise the nation. It also gave away time and space for North Vietnam to build an integrated air defence system (IADS). The North Vietnamese understood strategy, and the IADS provided a link between strategy and task. It would provide air deniability and so draw out the war – a strategy of exhaustion applied to the US.
This meant the US was forced into a defensive mindset from which it was almost impossible to recover. The US was reactive in planning and vulnerable to operational surprise, even though the intelligence enterprise was aware of increasing North Vietnamese air activity. The Pentagon was under-prepared for events like the Gulf of Tonkin incident in 1964, the Tet Offensive in 1968 (which led to the siege at Khe Sanh), and the Easter Offensive in 1972.
Complicating the tactical task for the US was a self-imposed 30-mile buffer zone along the Chinese border and around Hanoi, and a 10-mile buffer around the port of Haiphong. While intended to minimise the risk of escalation and contain Soviet and Chinese involvement, it also allowed the unencumbered supply of war materiel, including the Soviet-delivered components of the IADS.
At the start of Rolling Thunder, policy, process and technology were fragmented to the point where the US faced the real possibility of losing the air war. It was only towards the end of the air campaign and the Linebacker raids that the combined weight of US air power was integrated and synchronised enough to destroy the North Vietnamese IADS. US air power eventually caught up with North Vietnamese decision-making, but it came at an extraordinary cost in lives and aircraft, measured in the thousands.
North Vietnam was quicker to understand the air deniability mission. The target was not US air power, it was the command and decision-making apparatus of the US military. North Vietnam also integrated its counter-air operations much faster than the US, which started the campaign with deep divides organisationally, doctrinally and culturally between Strategic Air Command (SAC) and Tactical Air Command (TAC).
While Washington directed the strategy, the weak link between military action and political outcomes meant USAF and USN air operations lacked a unified command arrangement, didn’t share intelligence or target lists, and integrated (joint) training before deployment didn’t exist.
The Vietnam air campaign can be divided into three phases between 1965 and 1975 – Operations Rolling Thunder, Linebacker I, and Linebacker II. Each demonstrated the growing influence of technology, characterised by the integration of intelligence and electronic warfare into US command and control systems and the use of precision-guided weapons.
This period also witnessed the rapid expansion of the North Vietnamese air defence capability from insignificant – no fighter aircraft, a small number of aging anti-aircraft artillery (AAA) systems and four fire control radars – to become the world’s most dense and lethal IADS.
This IADS was organised around four functions – active and passive early warning, air surveillance, air defence which included aircraft and surface-to-air-missile systems, and the capability to control fighter aircraft, often termed ground controlled intercept (GCI). It had an information layer, a sensor layer, an effects layer, and a command layer.
By the end of Rolling Thunder in 1968 the IADS was a tightly-coupled system with 400 radars, 8,000 AAA pieces, 35 S-75 Dvina (NATO codename SA-2 Guideline) SAM batteries, 32 Soviet-built MiG-21 and 15 MiG-15/17 fighters, plus another 108 fighters based in the PRC.
When the US re-commenced bombing in the North in 1972 during Linebacker I, proficiency and technology had increased on both sides. But the US still lagged behind North Vietnamese command situational awareness and decision-making capability, due to limitations in radar coverage, airspace denial, and integration of intelligence.
North Vietnamese air defence represented everything the US was not. The air defence headquarters in Hanoi worked with North Vietnamese land forces using high frequency communications between all command elements. It employed a common signals operating and planning process fed by extensive radar coverage, which allowed commanders to see the entire air battlespace on plotting boards and radar screens.
Radar coverage was augmented by over 5,000 signals intelligence (SIGINT) operators skilled in interpreting the increased air, logistics, weather checks, air traffic and other activities that preceded US bombing raids. Consequently, North Vietnamese air defences often had 30-40 minutes warning of an air attack, which was more than enough time to prepare for the disruption and denial of US aircraft.
North Vietnam also employed sophisticated deception measures that exploited weaknesses in US tactics, radar coverage, unencrypted voice communications, and the geographical constraints imposed by Washington.
The North Vietnamese were integrated and synchronised. Meanwhile, the US was integrated but a long way from being synchronised. Most crucially US commanders lacked the shared situational awareness necessary for a decision-making advantage.
US airborne radars had poor range and look-down capability, and ground-based air surveillance radars provided only limited coverage for deep strikes into North Vietnam. There was no coordinated effort to degrade and destroy the North Vietnamese IADS, and the US continued to view air superiority as a defensive task, preventing bombers from attacking US targets.
Unity of command and intelligence integration, essential for successful counter-air operations, was divided between USAF 7th Air Force and USN Task Force 77 (CTF-77) stationed in the Gulf of Tonkin, so that within a few months the planned strategic bombing campaign quickly decomposed to a limited tactical interdiction effort. This was further evidenced by the need to procedurally split theatre airspace into ‘route packages’ to aid coordination and deconfliction of strike formations.
Meanwhile the North Vietnamese IADS continued to grow and US aircraft losses mounted to extraordinary levels by today’s standards. Local commanders tried to make sense of the situation while Washington continued to impose constraints and metrics, such as sortie rates. This led to a scientific approach to the measurement of air campaign success, encouraging the wrong operational behaviours, poor decisions, and insufficient emphasis on operational art.
However, there were significant events to come which changed leadership behaviour and decision-making in Washington, and accelerated the integration of intelligence into air operations. This would move US air power slowly towards the required level of synchronisation.
Opening the Green Doors
US intelligence had been aware of the build-up of the North Vietnamese IADS as early as 1964, yet the dissemination of intelligence was constrained by policy, administration and technology barriers across NSA, CIA and the single service intelligence organisations. This was especially true for SIGINT.
SIGINT is intelligence derived from electronic signals and systems such as communications, radars, and weapons systems. It can provide an essential insight into adversary capabilities, actions, and intentions. However, the default is to constrain SIGINT in policy, process and organisational bureaucracy. This stems from the need for operational security in collection and force application.
The decision to release SIGINT is therefore subject to gain/loss decisions involving the benefits of providing intelligence to the operator, weighed against the potential downside of revealing sources and collection capabilities.
In Vietnam, three events involving the loss of life, materiel, and reputation progressively eased these restrictions and accelerated the release of intelligence to those who needed it most.
On April 4 1965 a flight of USAF F-105Ds was attacking a rail and road bridge complex 75 miles south of Hanoi. Despite US technical supremacy, a pair of MiG-17 Frescos shot down two ‘Thuds’ before the supporting USAF F-100 fighters could react. This was the first air-to-air victory by either side during the Vietnam air war, and it left the USAF reeling.
Three months later, following a raid by four USAF F-4C Phantoms on munitions facilities west of Hanoi, they were targeted by an SA-2 battery – one F-4C was shot down, and three aircraft were damaged. Two days later, 48 F-105Ds took part in raids known as Operation Spring High, but the North Vietnamese had an information and decision advantage, and had set a trap – the raid turned out to be against SA-2 decoys made from bamboo. The USAF lost six Thuds and five pilots to AAA in the raid and, once again, were outmanoeuvred by a more sophisticated and integrated counter-air system.
The third event was an international incident on May 8 1966 when four EB-66 EW aircraft and four F-4Cs inadvertently strayed into Chinese airspace. Four MIG-17s were scrambled to intercept the US aircraft, and the ensuing dogfight resulted in the loss of a Chinese MIG-17. Beijing threatened escalation, while the USAF claimed it had not crossed the border.
But imagery of jettisoned Phantom fuel tanks in the PRC provided evidence which infuriated Washington. The Pentagon demanded an investigation into why the aircraft had not been warned of the airspace violation. It became clear the problem lay not with SIGINT collection, but with the reliability and speed of dissemination of intelligence to aircrew via the US’s Hammock warning system.
Project Hammock had been in existence since November 1965 and was the result of an operational need for better tracking data on air activity to support raids deep into North Vietnam and provide early warning of low-level MiG attacks.
Hammock involved the collection of North Vietnamese air defence communications at an intercept site in Danang, and the establishment of an encrypted network between the USAF control and reporting post (CRP) at Monkey Mountain near Da Nang, and the US 7th Fleet in the Gulf of Tonkin to the US Navy controller called Red Crown.
The 7th AF Tactical Air Control Centre (TACC) at Tan Son Nhut Air Base was added to the network, but the system incurred duplication and it was slow. The manual conversion of tracks and the transmission to the CRP and TACC could take anything from 12 to 30 minutes to reach aircrew via the busy guard communications channel, and there was no assurance warning messages were received.
The USAF investigation into the PRC border incursion resulted in airborne communications relay platforms being integrated into the Hammock architecture. The TACC at Tan Son Nhut was shut down and a new one established at Monkey Mountain called TACC-North Sector (TACC-NS), with embedded staff cleared to handle SIGINT.
To further build situational awareness the SAC Lockheed EC-121K Rivet Top was introduced into air operations in 1967 and integrated into Hammock. The Rivet Top provided an airborne extension to the TACC-NS capability. Key technologies included the QRC-248 set which could display Soviet identification friend or foe (IFF) returns from the North Vietnamese MiGs, and display data from the SA-2’s Fan Song radar.
There was further integration of the NSA Ironhorse system which generated a visual display of SIGINT derived from North Vietnamese morse and non-morse air defence communications. The Ironhorse system provided a level of computer-enabled automation which accelerated the manual plotting systems at the heart of Hammock.
But the problem now was the sheer volume of data as air defence traffic rose exponentially during Rolling Thunder, and the Hammock system became overwhelmed. This required increasing levels of automation and improvements in latency.
Air combat activity peaked in 1967, and in early 1968 events on the ground diverted the USAF and USN air operations away from Rolling Thunder in the north to support the siege at Khe Sanh in the south. The Tet Offensive at the end of January further diverted attention, and poor weather prevented attacks on the north. President Johnson finally ordered a halt to the bombing campaign in April 1968.
Between the end of Rolling Thunder in 1968 and the start of Linebacker I in 1972, the US made significant improvements in its technology and TTPs. Yet the latter stages of the air war were again impacted by the ongoing integration of intelligence into counter-air operations, and it was the creation of a new weapons control facility – called Teaball – which finally allowed the US to achieve its goal of air superiority and bring North Vietnam to the negotiating table.
Linebacker I lasted seven months, and was in response to the surprise North Vietnamese crossing of the Demilitarised Zone (DMZ) in March 1972, known as the Easter Offensive. Linebacker II was an 11-day operation in December 1972 and would become the final bombing campaign before the signing of the peace accords in Paris.
President Nixon had turned to air power because he wanted the withdrawal of 70,000 ground forces to go ahead regardless of the invasion so, in preparation, the number of F-4s in South-East Asia was increased by 185 to 374 and the number of B-52s increased from 86 to 210.
In the first three months of Linebacker I the US lost 48 aircraft, 21 to MiGs and 27 to ground-based air defences. When the US lost another 13 aircraft the Commander 7th AF, General John Vogt, reported to the USAF Chief of Staff they were losing the air war.
Poor situational awareness for raids to the north and west of Hanoi remained a major problem, so Vogt initiated a project which would synchronise strike and counter-air missions to a level necessary to overwhelm the North Vietnamese IADS.
Teaball utilised a previously unexploited source of communications intelligence (COMINT) that included azimuth and range positions from North Vietnamese radars. These were passed by line of sight communications to the intercepting MiGs by GCI. The communications were intercepted by U-2 aircraft and downlinked to USAF operators in Thailand. This GCI link had in fact been identified as early as 1965 by US Army intercept operators, but had not been recognised for its significance due to a lack of air domain expertise.
The range and azimuth data were fused in real time with other North Vietnamese tactical air communications, and 7th AF and CTF-77 multi-sensor information was combined into Teaball, creating an unimagined level of understanding of the battlespace. So despite the heavy losses in the early stages of the operation, by the end of Linebacker II the US had finally penetrated the North Vietnamese command layer, gained decision-making advantage, and air superiority.
The tables had been turned on the MiGs which by this stage were grounded. The IADS was rendered ineffective by a broader bombing campaign which denied the resupply of SAMs. The North Vietnamese eventually ran out of missiles, having fired 1,240 during Linebacker II alone.
Integration was an important factor in the outcome of the Vietnam air campaign, but a higher-order function was synchronisation. Once the US had synchronised the political, operational, tactical, physical and information domains, it was a match for the North Vietnamese. But before then, the US was reactive and defensive, and was losing.
Force Multiplier – Early Warning and Control
In a modern context, viewing future multi-domain operations simply as a function of tactical integration is unlikely to achieve the required decision-making tempo, advantage, and operational outcomes. A focus on synchronisation will encourage new thinking, and avoid framing our operational challenges exclusively in terms of platforms and legacy counter-air doctrine.
Synchronisation has a relationship with time, whereas integration does not. While our competitors chase systems integration, we should raise the bar and build the narrative around synchronisation.
The legacy of Hammock, Ironhorse, Teaball, and Rivet Top lives on in a single platform concept, articulated fifty years ago by the 13th AF Technical Research Detachment at Udorn in Thailand. ‘The Teaball concept should be integrated into the Airborne Warning and Control System (AWACS). The concept of an air mobile weapons control centre which could be co-located with a ground COMINT source, in any theatre, should be developed.
‘The AWACS aircraft would receive COMINT plots, via secure satellite data link, either as a computer-generated track or voice tells. If space and payloads permit, COMINT collection stations should be incorporated into AWACS. The improved air picture that will be available with the advent of AWACS, when integrated with the information available in COMINT, will provide a degree of command and control never before achieved.’
John Conway is the Managing Director and senior analyst at Felix Defence. He has extensive operational experience as a fast jet operator and senior commander across the South Atlantic, Cold War Europe, Balkans and Middle East theatres of operation. He is a board member at the Sir Richard Williams Foundation and spent over a decade working in the Australian Defence industry.