By Major E. Aaron Brady
Boar 81, we’ve got approval to strike the convoy you found. This will be Type 2 control, single GBU-38s, 30-second spacing, attack from the north. Your target is a column of vehicles near coordinates 123 456. Nearest friendlies are 40 kilometres east. Expect weapons clearance on final…
The situation described above is becoming increasingly common in US and NATO air operations. Aircrew found a legitimate target in an area in which risk of fratricide is nil, yet the strike is being closely controlled by ground personnel hundreds of kilometres away via satellite radio and using Close Air Support (CAS) procedures. The trouble with this example – based on an actual occurrence during Operation INHERENT RESOLVE – Is that it illustrates the US military’s misapplication of CAS procedures to situations for which those procedures were not designed. This issue largely stems from two factors: a continued inability to resolve tensions inherent in operational frameworks (how we divide battlespaces up for command and control purposes) and weaknesses within United States and European doctrine that cleaves all air-to-surface operations against enemy military capabilities into either Air Interdiction (AI) or Close Air Support (CAS) categories.
The framework issue is discussed often, and therefore largely ignored in this article. However, the doctrine issue remains mostly unaddressed. The main notable exception is a 2005 RAND study entitled Beyond Close Air Support. More importantly, the flaws in the doctrinal models reflect deeper issues with the theoretical foundation western militaries use to understand air-to-surface operations. This article attempts to resolve this issue by presenting a more nuanced theory of counterland operations by examining the differences between the CAS mission and CAS procedures as well as addressing why this difference matters.
Understanding the purpose of CAS and the intent of CAS tactics, techniques, and procedures (TTPs) as codified in US Joint Publication (JP) 3-09.3 Close Air Support helps one recognise that CAS TTPs are intended to mitigate the risk of fratricide. However, the CAS mission is focused entirely on affecting an enemy in close support of a friendly land force. This, in turn, suggests that while many air actions may fall under the purview of the CAS mission, only a subset of these missions require the level of control typically used. The current poor understanding will create significant issues if the US or NATO fights a peer adversary. Ground commanders, Tactical Air Control Parties (TACP), and aircrew should foster a culture of flexible TTP application based on risk assessment to enable a more effective tempo depending on the specific operational environment.
Examining Definitions of CAS
Determining what defines CAS as a mission begins with JP 3-09.3 Close Air Support, which views CAS as an action by fixed-wing or rotary-wing aircraft against targets in close proximity to friendly forces which require detailed integration of each air mission with the fire and movement of those forces. The two key phrases most often keyed upon by CAS-focused communities like the TACP and A-10 tribes in the US Air Force are ‘close proximity’ and ‘detailed integration.’
Interestingly, the NATO definition of CAS includes the same definition almost word for word but adds that TTPs are executed ‘for fratricide avoidance and targeting guidance performed by a […] Forward Air Controller.’ British air and space power doctrine does not include detailed integration in its most basic definition but notes that ‘intensive air-land integration and coordination’ is necessary for fratricide prevention and target identification. Most other American allies match either the NATO or US definition. The US and its allies, therefore, agree that the mission of CAS is airstrikes in close proximity to ground forces and that detailed integration is needed. However, most allied doctrine notes explicitly that the purpose of detailed integration is to either mitigate fratricide risk or enable target correlation.
Close proximity is clearly a subjective term. Close means one thing to an infantry unit defending urban terrain and something entirely different to an armoured formation attacking through a desert. Doctrine even describes close as situational. Likewise, detailed integration may encompass entirely different issues depending on the situation. So, even though these two clauses are the cited hallmarks of CAS, one cannot easily list out the explicit characteristics required to meet the conditions because they are too situationally dependent. JP 3-09.3 even states that when deciding if a mission should be considered CAS or not, ‘the word ‘close’ does not imply a specific distance […] The requirement for detailed integration because of proximity, fires, or movement is the determining factor.’ Therefore, even though proximity is considered one of the two main factors, the emphasis for describing CAS is detailed integration.
Three main elements drive a need for detailed integration: proximity, fires, or movement. These elements are multifaceted in the ways they influence air-ground integration. Proximity presents the most obvious issue in CAS: risk of fratricide. There is also a risk to the aircraft due to their proximity to surface-based fires which requires mitigation. Proximity further mixes with fires and movement to suggest another theme not mentioned in any of the definitions. Airstrikes occurring within a land commander’s area of operations (AO) may have a considerable impact on future actions by the effect those strikes may have on the enemy, the terrain, or civilians. These effects might be long-term, such as the destruction of crucial infrastructure or critical damage to military equipment, or short-term like the psychological effect of a large airstrike on an enemy unit. In either case, the land commander must both approve the strikes – in a sense ‘buying’ the effects of the attack – and ensure that the effects facilitate the overall operation. Considering fires and movement, the intent of CAS is to strike targets that directly enable the land scheme of maneuver. Doctrine hints at some of these points. This discussion highlights a weakness prevalent in all the doctrinal definitions of CAS that feeds into the misunderstandings throughout the US and allied forces: the definitions describe what CAS is, not the purpose of CAS. This is due in no small part to the way that most doctrine organises the various missions of air power.
The Counterland Doctrinal Framework
Once again, there is a large degree of consensus between the US and its allies over air power’s mission structure. US JP 3-0 Joint Operations simply classifies most air power missions within the various joint functions; most of the subjects discussed in this essay naturally fall under fires. In contrast, NATO doctrine creates a hierarchy of air missions. Air attack encompasses most missions which directly influence an enemy. One subset of attack is counter-surface force operations, under which falls air power contribution to counterland operations, which in turn incorporates two missions: AI and CAS.
UK doctrine closely aligns with NATO thinking. The US Air Force theory lies between the US joint doctrine and European concepts. It describes all-action intended to influence an enemy’s land forces as counterland which includes just two sub-missions: AI and CAS. The US Marine Corps presents a slightly different perspective. Marine thinking classifies six functions of Marine aviation, one of which is offensive air support (OAS). OAS incorporates CAS and deep air support (DAS), which includes AI, armed reconnaissance, and strike coordination and reconnaissance (SCAR). Of note, Marine doctrine states explicitly that ‘detailed integration is accomplished using positive control’ and that ‘positive control is provided by terminal controllers [JTACs].’ This listing shows that, except for US joint and Marine Corps doctrine, militaries tend to organise CAS and AI under a broader counterland concept (see Figure 1). Therefore, most US and NATO service members view CAS as a subset of a counterland concept.
CAS, as shown earlier, occurs close enough to friendly land forces that strikes require detailed integration. AI – the other half of counterland operations – occurs far enough away that this level of integration is unnecessary. Adopting a more conceptual view, the larger counterland mission set is enemy-centric – any counterland mission focuses on affecting an enemy’s combat system. AI and CAS, though, are friendly-centric – the doctrinal difference between the two lies in the level of integration mandated by the proximity of friendly land forces. Harkening back to the earlier identification of fratricide risk as to the primary reason demanding detailed integration with target nomination as a close second, we arrive at the crux of the issue.
To solve these two problems, CAS is differentiated from AI in that while executing CAS, aircrew does not have weapons release authority. By mandating that the land force commander must approve target nomination and weapons release and because the land commander is the authority for expenditure of weapons in the assigned area of operations, the various systems seek to resolve the two critical issues associated with airstrikes near friendly land forces. This clarification enables one to define the purpose of the CAS mission while still acknowledging the characteristics that separate it from AI.
The Purpose of CAS: A Mission-Based Definition
CAS is an air mission flown in close support of land forces to disrupt, degrade, or destroy enemy forces. These enemy forces are in close enough proximity to friendly land forces that risk mitigation mandates detailed coordination between the air and land forces. This definition does not roll off the tongue as easily as the current definition in JP 3-09.3 but does address both what the CAS mission is in addition to its characteristics and requirements. By creating a definition that addresses the purpose of CAS, we introduced the key elements that form the basis for CAS procedures.
Evaluating CAS Tactics, Techniques, and Procedures
CAS TTPs intend to mitigate the risk of fratricide and integrate air effects into a larger fire support plan by efficiently nominating, correlating, and approving weapons release against targets. A process termed Terminal Attack Control accomplishes this goal, hence the name for the person that controls CAS strikes, the JTAC. Standardised communication – most notably the CAS Briefing, referred to as the 9-Line – and specific weapons release authorities and parameters combine to achieve the overall intent. Compared to defining the purpose of CAS, deducing what CAS TTPs intend to do is simple. However, two major presumptions within the CAS TTPs are not readily plain and may cause issues in a large-scale conflict. These concerns drive the overall conclusion that there is a disconnect between the intent of CAS and the procedures laid out in current doctrine.
First, CAS procedures are almost entirely reactive. One can argue that planned CAS is an exception to this, but two factors reduce the strength of this claim. In this author’s decade of experience practising CAS, preplanned missions were far and away the exception rather than the norm. Mike Benitez’s article ‘How Afghanistan Distorted CAS’ shows that my experience is typical. Further, unless the plan includes detailed restrictions and weapons release authority, TACP and aircrew must still resort to using the entirety of CAS TTPs even during a planned mission. Nevertheless, in my experience reactive TTPs are so ingrained that even when strikes are planned in detail, both the controllers and aircrew have difficulty merely executing the plan. Decades of experience in the Middle East created a sense within the minds of both parties that 9-Lines need to be passed and confirmed on the radio even if there are no changes to the plan.
In stark contrast to aircrew performing AI, there is a limited ability within this paradigm for CAS aircrew to exercise initiative during battle. Since CAS is doctrinally a form of fire support, at first, this seems reasonable. However, on closer inspection, it should cause concern for several reasons. None of the doctrinal models with the notable exception of JP 3-0 specifies CAS as a form of fire support – it is air attack against land forces near friendly forces. This suggests that either the doctrinal models are flawed or that CAS is a distinct mission that happens to provide fire support, not a fire support mission that happens to be conducted by aircraft. Putting that point aside, ground-based fire support may conduct any number of missions with some level of internal initiative. Artillery raids or counter-battery fire are two examples. Further, harkening back to the doctrinal model point, CAS is quite different from other forms of fire support.
If lethal fire support for land maneuver is broadly divided into the categories of CAS and artillery, note that virtually all forms of artillery employ indirectly. That is, the artillery crew aimed at a location derived and passed from another source. CAS aircrew, on the other hand, receives target information from the JTAC and aim or guide the munitions themselves. Apart from bombing on coordinates, a technique not commonly used, CAS aircrew perform the aerial equivalent of aiming a rifle at the assigned target. Thus, even though they might be dropping a bomb from several miles distant, the aircrew is employing a direct-fire system as compared to other, indirect forms of fire support.
This distinction is significant because it shows that in many cases aircrew, unlike artillery operators, have the capability to find their own targets independent of specific target nominations from a controller. In recent years, CAS practitioners even added guidance to the doctrine explaining how CAS aircrew could nominate a target to a JTAC then receive a nomination and weapons release authority for the same target.
Going back to the concept of reactivity, one should now see the first issue clearly. CAS procedures, as an adjunct of fire support procedures, are inherently reactive. However, aircrew, unlike artillery operators, can identify targets independently. Therefore, the possibility exists that CAS can be performed proactively, given the right circumstances and presuming risk to friendly forces is mitigated. This suggests that the doctrinal models are correct: CAS is a distinct counterland mission that has fire support characteristics but is not inherently a fire support mission that happens to be performed by aircraft. If one accepts this notion, then we necessarily come to the second presumption behind extant CAS doctrine.
The reactive nature of CAS rests on the idea that detailed integration and risk mitigation are best accomplished through the close control of individual targets and, in most cases, individual attacks. This may be proper in many cases. In some cases, though, a single target or target set may require multiple attacks. This notion is part of the rationale behind Type 3 control in current doctrine, in which the land force commander approves multiple strikes on the same target. This type of control is still inherently reactive. However, with enough planning and an appropriate command and control capability, forces may be able to conduct CAS with a level of initiative unheard of today. Therein lies the problem with the mindset prevalent in the US military today.
The Grey Area between AI and CAS
While the earlier discussion showed that all counterland missions are inherently enemy-centric, but the difference between CAS and AI revolves around friendly land dispositions. AI is performed in areas in which the risk to friendly land forces is nil and therefore, only minimal integration is required. CAS, on the other hand, is performed in areas where the risk of fratricide exists and detailed integration into the land fires scheme is required. In practice, this means that battlespaces are cleanly divided into AI and CAS areas by the Fire Support Coordination Line (FSCL). Virtually any US doctrinal manual that discusses the FSCL conveys that the FSCL is not a dividing line between AI and CAS TTPs, but instead ‘delineates coordination requirements for the joint attack of surface targets.’ The line is closer to a command and control border than anything else. However, for all intents and purposes the mindset discussed at length that aircraft operating within a land component area of operations are conducting CAS, the FSCL becomes a border between AI and CAS areas. While joint doctrine attempts to negate this thinking.
Accepting the argument regarding CAS TTPs are inherently reactive, one sees how the FSCL creates a zone where aircraft can operate proactively and a second zone in which aircraft must function entirely reactively. The problem is the size of the second zone. During the major combat phase of Operation IRAQI FREEDOM, the US Army often placed the FSCL more than 100 kilometres from friendly troops. Obviously, friendly forces were at basically zero risks of fratricide if aircraft struck targets that far away. Additionally, most surface-to-surface fires were shot at targets well short of that distance.
Recent Warfighter exercises indicate that FSCLs today are often placed about thirty to 40 kilometres from the friendly lines. Even in this battlefield geometry, there is still a sizeable portion of the battlespace between the friendly front and the FSCL in which the risk of aircraft causing fratricide is minimal. This article does not address the operational framework concerns raised by this example, i.e., where should the line be, or should there be other coordination lines? Instead, this author posits that regardless of how a force organises a battlespace there will be a grey area.
This grey area is entirely subjective and based on the context of each individual battlespace. When analysing a battlefield, one can usually clearly lay out the areas near friendly troops where CAS procedures must be used to mitigate risk to friendly forces and integrate air strikes into the larger fires plan. One can also clearly see the areas in which no risk is present to friendly troops and the need for detailed integration into the fires plan is nil – the AI area. However, there will be many areas on the map that do not fit neatly into either category. These areas might be far enough away from friendly troops that fratricide risk is low but still close enough that detailed integration is required to deconflict aircraft with surface-to-surface fires.
Alternatively, there might be areas that, due to the nature of the terrain or the friendly scheme of maneuver, are relatively close on the map (say within a few kilometres) but the risk of fratricide is nevertheless quite low. These two simple examples illustrate the notion that between CAS and AI is a nebulous area that can be found in many battlespaces. The pressing concern for US and NATO CAS practitioners is to learn to conduct proactive CAS in these grey areas to achieve the purpose of CAS while retaining enough control to accomplish the intent of current CAS TTPs.
Finding Solutions to Enable Proactive CAS
The extant CAS paradigm relies on the idea that CAS fires must be reactive. A reactive mindset, however, is not conducive to success in a modern battlespace in which the speed of decision-making is paramount. The paradigm should allow for aircrew to proactively achieve the purpose of CAS – disrupting, degrading, and destroying enemy forces per a land maneuver commander’s intent and with minimal risk to friendly forces. The 2019 US JP 3-09 Joint Fire Support identifies the criticality of fast-paced decision-making in modern combat, emphasising that joint fire effects are best achieved through ‘decentralized execution based on mission-type orders.’ A myriad of options to do this is already within US doctrine.
The joint force could incorporate the US Marine Corps concept of the Battlefield Coordination Line into joint doctrine. This line allows land commanders to simply denote where the risk to friendly forces is low enough to justify AI TTPs. Whether land commanders and TACP utilise preplanned 9-Lines with Type 3 control, engagement areas with specific restrictions attached, or even restricted fire areas, the possibilities for enabling initiative to abound. If targets appear outside those areas, or the ground situation changes, then switch to close control of individual attacks. Nonetheless, in large conflicts, allow CAS aircrew to achieve the intent of CAS by providing enough freedom of action to enable initiative. US forces should foster a mindset that emphasises the concepts of mission command and decentralised execution – delegate decision-making authority to the lowest appropriate level. The simple fact is that US forces in all domains must make decisions faster than the enemy. A reactive CAS mindset virtually ensures a slow decision cycle. A proactive perspective, with proper risk mitigation, allows for thinking aircrew to engage the enemy faster with commensurate effects on the enemy’s tempo.
In summary, let’s review the key takeaways. First, counterland missions affect an enemy’s land military capabilities and consist of AI and CAS subsets. The only difference between these two is that CAS is executed in close proximity to friendly forces while AI is distant enough that detailed integration is not needed. Second, the purpose of CAS TTPs is to facilitate target nomination and mitigate risk to friendly ground troops. Third, the current US mindset is that a CAS mission must be controlled using individual 9-Lines for every target regardless of actual risk to friendly forces. The disconnect between the first two points and the third point creates a potentially dangerous concoction for CAS effectiveness during future major conflicts.
Land commanders, TACP, and CAS aircrew should train now to using various control methods to enable initiative on the part of aircrew. Whether that means more sophisticated uses of fire support coordination measures or learning to transition between CAS and AI TTP control methods flexibly is irrelevant. The point is to learn now, on bloodless training grounds, how to delegate initiative to the lowest levels to make decisions as rapidly as possible. The lessons learned today at Combat Training Centers and countless air-to-surface ranges around North American and Europe concerning how to conduct proactive CAS missions will pay dividends in a potential future conflict.
Major E. Aaron ‘Nooner’ Brady is a student at the US Army’s School of Advanced Military Studies. He graduated from the US Air Force Academy with a BS in History in 2006. He is a graduate of the US Air Force Weapons School A-10 course and is a senior pilot with more than 1,800 hours including more than 360 combat hours.
Header Image: A US Air Force A-10 Thunderbolt II maneuvers through the air during Red Flag-Alaska 19-2 at Eielson Air Force Base, Alaska, June 17, 2019. The exercise provides counter-air, interdiction and close air support training in a simulated combat environment. (Source: US Department of Defense)
 Mike Benitez, ‘How Afghanistan Distorted Close Air Support and Why it Matters,’ War on the Rocks, 29 June 2016; Clay Bartels, Tim Tormey, Jon Hendrickson, ‘Multidomain Operations and Close Air Support: A Fresh Perspective,’ Military Review, 97:2 (2017), pp. 70-9.
 Bruce R. Pirnie, Alan Vick, Adam Grissom, Karl P. Mueller, David T. Orletsky, Beyond Close Air Support: Forging a New Air-Ground Partnership (Santa Monica, CA: RAND Corporation, 2005).
 Joint Publication (JP) 3-09.3 – Close Air Support (Washington DC, US Joint Staff: Department of Defense, 2019), p. I-1.
 Allied Joint Publication 3.3(B) – Allied Joint Doctrine for Air and Space Operations (North Atlantic Treaty Organization, Standardization Office, 2017), p. 1-11.
 Joint Doctrine Publication (JDP) 0-30 – UK Air and Space Power, Second Edition (Shrivenham: Defence Concepts and Doctrine Centre, 2017) p. 34
 JP 3-09.3, p. I-2.
 Marine Corps Reference Publication 1-10.1 – Organization of the United States Marine Corps (Washington DC:, Department of the Navy, 2016), p. 6-1.
 JP 3-09, Joint Fire Support (Washington DC: Department of Defense, 2019), p. A-5.
 Pirnie et al, Beyond Close Air Support, p. 68.
 Travis Robison and Alex Moen, ‘Reinventing the Wheel: Operational Lessons Learned by the 101st Division Artillery during Two Warfighter Exercises,’ Military Review, 96:4 (July-August 2016), p. 75.
 JP 3-09, Joint Fire Support, p. IV-1.