CHAPTER 4

Defensive Operations

The ultimate purpose of any defense is to create conditions favorable to assuming the offense. The immediate purpose is to cause an enemy attack to fail. In addition, defensive operations are conducted to--

• Gain time.
• Concentrate forces elsewhere.
• Control key or decisive terrain.
• Wear down enemy forces.
• Retain tactical objectives.

The defender arrives first on the battlefield and, with the help of the engineers, molds it to his advantage. Based on the commander's intent, engineers site and emplace tactical obstacles to produce specific effects on the enemy. Fortifications allow fires from positions that best disrupt and destroy the attacker. Because of his survivability, the defender can postpone the commitment of major forces until the attack develops and then strike the extended enemy over selected and prepared terrain.

Engineers provide essential survivability and countermobility support to the light brigade defense. With this support, the force can position itself and fight from terrain where it otherwise could not survive, while simultaneously attacking the enemy's freedom of maneuver.

On a nonlinear battlefield, enemy forces will be bypassed, penetrated, or encircled without the overall loss of a defense's integrity. Providing support to defensive operations on a nonlinear battlefield is the biggest challenge facing engineers. The defender must identify the enemy's main effort and attack it with sufficient force and firepower. To achieve the required level of violence, the brigade must be able to attack the enemy throughout the entire depth of its formation from mutually supporting positions arrayed throughout the depth of the brigade's AO.

Engineer defensive doctrine and considerations for airborne, air-assault, and light infantry brigades are discussed in this chapter. It serves as an extension of FM 7-30. The purpose of this chapter is twofold. It--

• Details how brigade engineers integrate into the brigade's decision-making process to plan defensive operations and to track and control the current battle.
• Defines the role of the company commander (and his company) in executing engineer missions in support of the brigade defense.

DEFENSIVE CHARACTERISTICS

The mission of the brigade engineer and the company commander is to plan and execute engineer missions that enhance the brigade's ability to combine fires, obstacles, and maneuver to destroy an attacking enemy. The defensive plan that is effective and supports the tactical plan requires sequential planning and the understanding of the following characteristics:

• Preparation.
• Disruption.
• Concentration.
• Flexibility.

PREPARATION

To prepare for the defense, the brigade commander must be familiar with the capabilities and limitations of the enemy. The terrain must be analyzed in detail from all perspectives and then verified from the ground. The commander then organizes his defense with a mixture of both direct-fire and indirect-fire weapons (directed at the enemy's main threat). The capabilities of these weapons are enhanced by the terrain.

Engineers play an essential role in preparing the defense. Based on the commander's intent, engineers--

• Emplace tactical obstacles to produce specific effects on the enemy.
• Construct survivability positions to allow the brigade to sustain the fight.

Engineer success in the preparation phase depends on the ability of the brigade engineer to conduct integrated planning with the maneuver commander's staff. The brigade engineer must analyze the full range of engineer requirements of the total defensive framework: deep, security, MBA, reserve, and rear operations. He has to know and understand the capabilities of engineers on the battlefield. The brigade engineer also needs to know how much Class IV/Class V supplies are available and when resupply can be expected.

Engineer focus in the preparation phase is not limited to the close operation in the MBA. Each element of the defensive framework must be considered during engineer mission analysis and accounted for in the brigade scheme of engineer operations.

DISRUPTION

Disruption in the defense is achieved by--

• Defeating or misleading the enemy's reconnaissance forces.
• Impeding the enemy's maneuver.
• Disrupting the enemy's reserves.
• Neutralizing the enemy's fire support.
• Interrupting the enemy's C2.

Disruption counters the enemy's initiative and prevents it from concentrating combat power against a single part of the defense. The general goal of disruption activities is to--

• Force the enemy to fight in more than one direction.
• Fix the enemy in position under direct and indirect fires.
• Block the enemy's penetrations.

The method by which the brigade commander chooses to achieve this varies with the situation, but his ultimate goal is to spoil the attacker's coordination. The brigade's engineer planners and executors work closely with the brigade staff to ensure that M/S and engineer functions are integrated into the brigade's disruption activities. Enemy-reconnaissance efforts and probing attacks must be defeated without disclosing the defensive scheme of maneuver. Tactical obstacles are designed and emplaced to disrupt enemy formations and to cause the enemy to turn into a desired area. This prevents the enemy from concentrating irresistible strength against any portion of the defense.

CONCENTRATION

In the defense, the brigade commander concentrates forces to exploit or create an enemy weakness. This is achieved by designating a battalion as the main effort, with all other efforts and actions supporting and sustaining this effort. To concentrate combat power during the battle, the brigade may--

• Economize in some areas.
• Retain a reserve.
• Maneuver repeatedly.

Engineers support the concentration of combat power by employing obstacles, constructing fortifications, and providing mobility to counterattack or reserve forces. The principal role of the engineer in the concentration is to ensure that tactical obstacles are integrated with the defender's fires to disrupt, turn, fix, or block enemy forces. This facilitates the brigade commander's concentration of combat power. These efforts, combined with the construction of fortifications and protective obstacles, enhance the brigade's defense. The defender must be able to direct his actions at the enemy from a survivable position. Engineers also provide mobility assistance to counterattack and reserve forces, enabling the brigade commander to initiate offensive actions against a disintegrating enemy attack.

FLEXIBILITY

The brigade commander maintains his flexibility through--

• Detailed planning.
• Sound preparation.
• In-depth organization.
• Reserve retention.
• C2.

Ultimately, flexibility requires that the brigade commander see the battlefield to detect the enemy's scheme of maneuver in time to direct fires and maneuver against it. Commanders must be able to employ counterattack and reserve forces at any time.

Engineers assist in maintaining flexibility by--

• Using situational obstacles in the MBA.
• Task-organizing for rapid transition to the offense.
• Improving or maintaining routes needed to shift forces.

Situational obstacles in the MBA are designed to provide the commander with time and space, enabling him to react to an enemy attack. They can be employed in a reinforcing mode, applied to an existing effort, or emplaced by themselves. Mobility requirements are a fundamental component of flexibility. Engineer planners at the brigade must address mobility requirements of the reserve and counterattack forces. This requirement is met through the task organization of engineers to these forces and through positive control of brigade obstacle efforts in anticipation of a rapid transition to offensive operations.

DEFENSIVE PATTERNS

Brigade defensive operations generally take one or two traditional patterns: mobile and area. The fundamental difference between these patterns is their focus-and-defeat mechanism. The focus of light engineer effort, unit missions, and task organization are all inseparably linked to the focus-and-defeat mechanism of each type of defense.

MOBILE DEFENSE

The focus of the mobile defense is the destruction of the attacker within the depths of the defensive sector through envelopment by a counterattacking force. The mobile defense uses a combination of offensive, defensive, and delaying actions. It is characterized by relatively small forces forward and by the use of maneuver, supported by obstacles, to take the initiative. The mobile defense requires a large reserve with mobility equal to or greater than that of the enemy to counterattack and envelop. It cannot be conducted unless the temporary loss of some terrain is acceptable. Divisions or higher HQ normally conduct a mobile defense, with brigades being used to hold strongpoints in restrictive terrain. While armored forces retain the required mobility to conduct the mobile defense, air-assault forces are also well suited for these operations. Frequently, during mixed operations in restrictive terrain, light forces conduct the delaying action, setting the conditions for the armored force to counterattack.

Engineer support to the mobile defense focuses on--

• Using obstacles to attack enemy maneuver.
• Providing mobility to reserve or counterattacking forces.

To facilitate this support, obstacle-zone planning received from the division and obstacle-belt planning received from the subsequent brigade are directed at the enemy's most likely COA rather than the terrain. Belts are aimed at the enemy's maneuver in the brigade sector to supports its destruction by the counterattack. Therefore, obstacle-belt planning is more restrictive. It reduces the flexibility of the battalions and allows the brigade commander to concentrate obstacle effort in key areas, ensuring the mobility of the counterattack. Mobile defense operations predominantly require turn, fix, and disrupt obstacle groups and are resourced by the brigade.

Survivability effort is closely tailored to a force-oriented defense. To create the conditions for a counterattack, the battalions must fight throughout the depth of their sector from multiple primary and subsequent battle positions (BPs). This is especially true when the brigade is participating in a mobile defense using air-assault forces or when armor forces are task-organized to the brigade. Protective-obstacle effort during the mobile defense covers the full spectrum of effort. Minimal protective-obstacle effort is required forward as the defense is geared toward a proactive fight. Protective-obstacle effort is concentrated where the enemy penetration must be stopped to allow the counterattack to take place.

The defeat mechanism of the mobile defense is the counterattack by a large reserve with mobility superior to the enemy force. The brigade engineer supports this mobility requirement in two ways. He--

• Uses obstacle-control measures to ensure that battalion obstacle efforts do not affect the brigade reserve's freedom to maneuver.
• Ensures that the reserve has the required engineer support to maintain its mobility during the counterattack.

AREA DEFENSE

The area defense is the principal defensive pattern employed by the light forces. Its focus is on denying the enemy access to specific terrain. The area defense is organized to absorb the enemy into an interlocked series of positions from which it can be destroyed. The area defense differs from the mobile defense in that the bulk of defending forces deploy to hold specific terrain. To accomplish this, forces use a combination of defensive positions and small mobile reserves. Commanders organize the defense around the static framework provided by the defensive positions, seeking to destroy enemy forces with interlocking fires or local counterattacks.

The focus of engineer effort is on providing the maneuver commander with the ability to hold terrain, while enabling the brigade to concentrate fires from static positions. During the area defense, engineer involvement in the terrain analysis becomes vital. They identify key and decisive terrain that supports the commander's concept of the operation. During obstacle planning, the brigades use obstacle-control measures to give maximum flexibility to the battalions while focusing tactical-obstacle effort on the retention of terrain. The brigade engineer must ensure that the battalions are resourced to employ turn, fix, and block belts. They are the principal obstacle effects in the area defense.

Survivability effort in the area defense must accomplish the following:

• Enhance the brigade's ability to accurately concentrate its fires from static positions.
• Provide the force with an increased level of protection from the sustained effects of enemy fires.

Frequently, the enemy force is unable to bypass brigade forces and is forced to conduct assaults on static positions to suppress or defeat concentrated fires. This increases the battalion's requirements for not only survivability but also protective obstacles.

Supporting defensive positions and small, decentralized mobile reserves are key components of the defeat mechanism that the brigade engineer must consider during planning and preparation. He must ensure that the tactical-obstacle effort of adjacent brigades is coordinated and mutually supporting and that it achieves an interlocking defense. The brigade engineer accomplishes this by closely monitoring the efforts of the maneuver battalions. He uses the battalion's planned groups and the status of obstacle and survivability effort to ensure a focused effort and to deconflict potential problems.

ENGINEER PLANNING AND PREPARATION

The engineer estimate provides the planning framework for engineer planners and executors supporting a brigade defensive operation. As presented in Chapter 2, the engineer estimate is an extension of the military decision-making process. The military decision-making process is molded to fit the situation, whereas the engineer-estimate steps focus on considerations that are peculiar to engineers supporting a defensive mission. Figure 4-1 shows some examples of engineer-estimate considerations in the defense, principally focusing on obstacles and survivability.

OBSTACLE FRAMEWORK

To understand obstacle integration, engineer planners and executors must understand obstacle definitions and concepts. The combined arms integration of fires and tactical obstacles is crucial to achieving success in the defense. Obstacle control, intent, and resourcing are top-down driven (initiated by the brigade engineer), whereas the process of integrating the actual obstacle location with fires is bottom-up driven (initiated by the company commander and TF engineers). FM 90-7 defines and details obstacle doctrine. Its comprehension and application is a prerequisite to planning engineer support for the brigade in the defense.

OBSTACLE CLASSIFICATION

An obstacle is any physical characteristic of the terrain--natural, man-made, or cultural--that impedes a force's mobility. Obstacles are inherent to the battlefield as one of the military aspects of terrain; however, obstacles are not just terrain features. Friendly forces can use obstacles to modify the terrain to support the commander's scheme of maneuver. Obstacles are classified into two categories:

• Existing.
• Reinforcing.

EXISTING OBSTACLES

Existing obstacles are obstacles that are present on the battlefield as inherent aspects of the terrain. The types of existing obstacles are--

• Natural.
• Cultural.

Natural obstacles are terrain features, such as rivers, forests, or mountains. Cultural obstacles are man-made terrain features, such as towns, canals, or railroad embankments. Natural and cultural terrain features are analyzed based on such characteristics as hydrology, slopes, soil and rock, elevation, vegetation, and built-up areas.

Terrain features are affected by the weather. This must be considered when analyzing the terrain for existing obstacles. Weather conditions can impact mobility by influencing trafficability. For example, farmland could offer excellent mobility during dry-weather conditions; however plowed farmland could impede mobility during wet-weather conditions.

The analysis of natural and cultural terrain features and the effects of weather are consolidated and graphically coded based on the effects they have on a force's mobility. The graphic codes are--

• Unrestricted.
• Restricted.
• Severely restricted.

FM 34-130 provides examples of the unrestricted, restricted, and severely restricted terrain criteria. The analysis of existing obstacles is presented (along with other OCOKA analysis) graphically in a MCOO.

When evaluating existing obstacles, the brigade engineer should review the compiled MCOO. This helps determine what effect (disrupt, fix, turn, or block) the terrain (independent of friendly fires and maneuver) has on the attacker. This facilitates the entire brigade's planning process, especially when determining COAs and allocating resources.

REINFORCING OBSTACLES

Reinforcing obstacles are any obstacles specifically constructed, emplaced, or detonated by enemy or friendly forces. The categories of reinforcing obstacles are--

• Tactical.
• Protective.

Tactical Obstacles

Tactical obstacles are used to directly attack the enemy's ability to maneuver, mass, and reinforce. All tactical obstacles are designed to produce a specific obstacle effect. They are integrated into the force's scheme of maneuver and direct-and indirect-fire plans. Types of tactical obstacles are--

• Situational.
• Directed.
• Reserve.

Situational Obstacles. A situational obstacle is a tactical-obstacle-emplacement capability held in reserve; it is a "be-prepared" obstacle. Situational obstacles provide the commander flexibility for emplacing tactical obstacles based on the battlefield development. Execution is triggered by friendly or enemy actions or a combination of the two. Situational obstacles can be shifted to different locations. However, they must be within the executing maneuver unit's obstacle-control measure. FM 90-7, Chapter 7, covers situational-obstacle doctrine.

Situational obstacles contain three components of obstacle intent (obstacle effect, a defined target, and a relative location) and require integration into the decision support template (DST) to be executed effectively. The situational-obstacle plan must identify the trigger action and execution criteria at a specific decision point and the necessary subunit instructions to emplace and cover the obstacle. There are three possible ways for the brigade engineer to employ situational obstacles. He can--

• Plan and execute the obstacle at the brigade level.
• Identify the obstacle intent and allocate the resources to a subordinate unit for execution.
• Allocate the resources for the obstacle to a subordinate unit for planning and execution.

Directed Obstacles. The higher commander directs these obstacles as specified tasks to a subordinate unit. FM 90-7, Chapter 6, covers directed-obstacle planning. The brigade obstacle must be within an obstacle zone. The maneuver battalion commander can authorize obstacles anywhere in his directed-obstacle belt. This control procedure ensures the control of the entire tactical-obstacle effort.

Reserve Obstacles. Reserve obstacles are obstacles for which the commander restricts the execution authority they are "on-order" obstacles. Reserve obstacles are located at specific locations and deny the enemy the use of a small area. Only the division commander can authorize directed or reserve obstacles outside an obstacle zone. In turn, only the brigade commander can authorize directed or reserve obstacles outside an obstacle belt. The commander usually specifies the unit responsible for obstacle emplacement, guarding, and execution. The commander must clearly identify the conditions under which the obstacle is to be executed. FM 90-7, Chapter 7, covers reserve-obstacle planning.

Protective Obstacles

Protective obstacles are a key component of the brigade's survivability operations. They are employed at the small-unit level (platoon and company team) to protect the defending force from the enemy's final assault. The authority to emplace protective obstacles is normally delegated to the company. Unless specifically stated, protective obstacles are not restricted by obstacle-control measures. Emplacing units remove protective obstacles before departing the area. A unit must report protective obstacles. FM 90-7, Chapter 8, details protective-obstacle planning.

OBSTACLE PRINCIPLES

Commanders use obstacles to--

• Attack enemy maneuver.
• Multiply the effects and capabilities of firepower.

Obstacles alone cannot shape the brigade battlefield. They are used to reinforce existing obstacles, to shape an engagement area (EA), or to enhance fires. Fires cannot be massed everywhere; therefore, the battlefield must be shaped to ensure that the enemy is at the decisive point of our scheme of maneuver. It is the combination of fires and obstacles that shapes the brigade battlefield to mass combat power at the decisive point. FM 90-7, Chapters 4, 5, and 6, covers obstacle planning.

To assist in focusing the engineer estimate toward defensive operations, critical obstacle and survivability principles must be reviewed. They are--

• Obstacle integration.
• Obstacle control.
• Obstacle planning.
• Survivability planning.

OBSTACLE INTEGRATION

It is the process of planning, preparing, and executing obstacles with fires and maneuver to achieve a desired effect. The purpose of obstacle integration is to--

• Establish a clear link between the brigade's force allocation, direct-and indirect-fire plans, maneuver, and the obstacle plan.
• Ensure that weapons capabilities and obstacle effects are compatible.
• Provide obstacle control.
• Ensure that obstacles are designed to achieve the specified effect.

For obstacles to have a dynamic impact on the brigade battle, the following must be considered:

• Intelligence.
• Obstacle intent and graphics.
• Fires and obstacle effects.
• Obstacle-control measures.

Intelligence

The brigade's success on the battlefield depends largely on the ability of the commander to see the battlefield. Through the assistance of his S2 and the engineers supporting him, the commander must identify how the enemy may use the existing terrain to gain an advantage. This is particularly true when looking for the enemy's vulnerability. The maneuver commander does this through the IPB process. The IPB process helps the commander to--

• Decide where to kill the enemy.
• Define the decision point based on the terrain, enemy tactics, and vulnerabilities.

Terrain analysis is the first step for any operation. Obstacles are one of the five military aspects of terrain. They are normally existing obstacles; however, reinforcing obstacles may be present in some situations. The identification of mobility corridors (MCs) and AAs help the commander to--

• Determine where the enemy can maneuver.
• Identify any limitations on friendly maneuver.

The brigade engineer assists in this step by identifying the effects that the terrain (independent of fires and maneuver) imparts on the attacking force. This greatly assists the brigade commander in seeing where the enemy will go and how he will attack.

The next step is to determine the size of the enemy force that each AA can support so friendly forces can be properly allocated. An important consideration is to identify any terrain that may cause the enemy to change formation. This terrain is identified by the brigade engineer while evaluating the MCOO.

In the last step, the commander and staff consider where the enemy is vulnerable. Attacking the enemy at the point of vulnerability with fires and obstacles can lead to a decisive victory. Obstacles should be designed against an enemy's breaching vulnerability. If they can be easily breached by the enemy, they may be ineffective to use to shape the battlefield.

Obstacle Intent and Graphics

Obstacle intent and its related supporting effect graphics convey how the brigade commander wants to use obstacles, integrated with fires, to support his scheme of maneuver and to affect enemy maneuver. His obstacle intent provides purpose and unity of effort to the obstacles planned or emplaced by subordinates. Obstacle intent identifies the following:

• Target (enemy force).
• Obstacle effect.
• Relative location.

The brigade commander must understand that it is not obstacles that create the obstacle effect but the combination of fires and obstacles. All tactical obstacles produce one of the following obstacle effects:

• Disrupt.
• Turn.
• Fix.
• Block.

FM 90-7, Chapter 3, provides details on obstacle intent and Appendix C of that manual provides details on obstacle resourcing.

Commanders use obstacle-effect graphics to convey the specific effect they want the obstacles to have on the enemy (see Figure 4-2). TF commanders use them to indicate the general location of TF obstacle groups. Obstacle-effect graphics can be used to indicate the desired effect of zones and belts. The inclusion of obstacle-effect graphics is not a requirement for brigade obstacle belts.

Fires and Obstacle Effect

Obstacle integration creates an inseparable link between the brigade's fires and obstacles. Neither fires nor obstacles employed by themselves can match the effectiveness achieved by both when they are integrated. The brigade commander, with the brigade engineer's help, establishes his obstacle intent concurrent with organizing and developing the fire plan. Each component of obstacle intent directly impacts the fire plan. Fire-control measures are required to maximize obstacle effect. Obstacle planning does not drive fire planning. Obstacles and fire-control measures must be planned, adjusted, and executed to meet the commander's intent. For more information on fires and obstacle effects, see FM 90-7, Chapter 3.

Obstacle-Control Measures

Obstacle control is a tool that commanders use to assign responsibility and provide control for obstacle emplacement. To achieve obstacle control, commanders use obstacle-control measures and graphics. Obstacle-control-measure graphics allow a commander to graphically define the area in which subordinates can plan and emplace tactical obstacles (see Figure 4-3).

Obstacle-control measures are specific measures that simplify granting obstacle-emplacement authority and providing obstacle control. Obstacle-control measures are--

• Zones.
• Belts.
• Groups.
• Restrictions.

The divisions and the corps HQ establish zones for the brigades, and the brigades establish belts for the battalions.

Zones. Obstacle zones are a graphic control measure the division uses to limit the area where subordinates are authorized to emplace tactical obstacles. Obstacle zones are planned for at the division and assigned to brigade-level forces. Obstacle zones do not cross brigade boundaries. By not crossing brigade boundaries, obstacle zones enhance C2, establish specific responsibilities for the subordinate commanders, and facilitate future operations. Obstacle zones drive the initial flow of obstacle material to the brigade. The division commander may or may not assign an intent to his zones. If he assigns an intent to a zone, he is relating the criticality of that zone and its intent to the division operation. The brigade will normally only see turn or block intents assigned by the division commander.

Belts. Obstacle belts are a graphic control measure that brigade commanders use to constrain tactical-obstacle employment.

They plan obstacle belts within assigned obstacle zones to grant obstacle-emplacement authority to subordinate units. The brigade uses obstacle belts to allow TF commanders the maximum flexibility to emplace tactical obstacles.

Brigade commanders use obstacle belts to focus countermobility effort and fire planning. Obstacle-belt intent specifies to TF commanders what effect the combined results of fires and obstacles must have on the enemy's ability to maneuver.

The brigade commander designates obstacle belts to his subordinate maneuver battalions based on the division's obstacle zone(s) and the brigade's scheme of maneuver. These belts focus and synchronize the brigade's obstacle effort. Obstacle belts generally straddle the enemy AA that the maneuver battalions are allocated against.

The brigade may assign an obstacle intent to an obstacle-control measure or obstacle belt (see Table 4-1). A sample obstacle intent would be: "The intent of obstacle belt D3 is to fix the enemy's motorized rifle battalion (MRB) on AA 3 in EA Fox." The supporting obstacle-effect graphic and obstacle intent facilitate the throughput of Class IV/Class V (obstacle) supplies to the maneuver battalions. The brigade engineer resources obstacle belts based on the--

• Intent.
• Standard obstacle-planning factors.
• Sum of MCs that the belt straddles.

This provides an initial estimate of the linear obstacle effort needed to achieve the belt's intent. Obstacle belts do not cross maneuver battalion boundaries for the same reasons that zones do not cross brigade boundaries.

Groups. Obstacle groups are one or more individual obstacles grouped to provide a specific obstacle effect. Obstacle groups are only permitted within the confines of the obstacle belt. The battalion commander designates obstacle groups to focus individual obstacle effort and indirect and direct fires. Obstacle groups directly target the enemy formation against which the maneuver companies (or teams) are allocated.

The maneuver battalion commander allocates groups within the obstacle belts based on the obstacle intent and the TF scheme of maneuver. The summation of the obstacle groups that the battalion directs must accomplish the obstacle-belt intent. In other words, if the battalion is given the responsibility for a belt that requires the enemy maneuver to be turned south, the TF commander is not limited to turn groups only. For example, the battalion commander could target a first-echelon enemy company with a disrupt obstacle group, followed by a turn obstacle group that denies a specific MC, and ending with a block obstacle group against other enemy battalions. The total effect of the obstacle groups turn an attacking dismounted enemy regiment to the south.

If the MC is restricted, point obstacles can be used to disorganize the force. Point obstacles are of irregular sizes and shapes and include all types of materials, such as antitank (AT) and antipersonnel (AP) mines and antihandling devices. They are used to add to the effects of existing and reinforcing obstacles or to rapidly block an enemy counterattack. One point obstacle in a platoon or smaller MC could achieve a disrupt effect, while several point obstacles in depth along the same MC can achieve a fix effect. This is extremely useful in restrictive terrain and for antiarmor ambushes. However, to achieve a block or turn, individual obstacle norms must be used.

Restrictions. Commanders may use obstacle restrictions to limit certain types of obstacles inside an obstacle-control measure (such as a belt). These restrictions ensure that subordinates do not employ obstacles with characteristics that impair future operations. It also allows the higher commander to focus the use of limited resources for the main effort by restricting their use elsewhere. Subordinate commanders have the right to be more restrictive than the higher commander; however, subordinate commanders cannot relax the higher commander's restrictions. Commanders can attach obstacle restrictions to each obstacle-control measure.

OBSTACLE CONTROL

In general, obstacle planning in support of brigade defensive operations is guided by three obstacle-control concepts. These concepts help shape the engineer countermobility effort for the brigade. They--

• Support the brigade's scheme of maneuver and the commander's intent.
• Balance maximum flexibility while providing focus to the obstacle effort.
• Facilitate future operations.

Support Current Operations

The brigade engineer and the company commander must understand the brigade commander's vision of the operation and the brigade's--

• Defeat mechanism.
• Main effort and when it changes.
• Synchronization requirements across the battlefield framework (close, deep, and rear).

These elements ensure that obstacle belts support the brigade's scheme of maneuver and commander's intent.

The defeat mechanism guides the brigade engineer in determining general areas that require obstacle effort and areas that must be free of obstacles or have restrictions. It also drives the type and amount of engineer support to the subordinate units.

The brigade commander's vision of the operation describes how the brigade will achieve the desired end state relative to friendly forces, the terrain, and enemy forces. This vision, along with the defeat mechanism, provides a general framework that brings together the elements of obstacle intent, target, effect, and relative location. The brigade engineer uses this framework to generally envision how subordinate maneuver commanders will fight. This is critical in anticipating the needs of and pushing resources to the maneuver battalions.

The brigade's main effort and when it changes, gives the brigade engineer a guide for determining obstacle-belt priorities and weighting the main effort with engineer resources (manpower and materials).

Certain synchronization requirements impact obstacle-belt planning across the defensive framework. The brigade engineer must consider brigade control and synchronization measures as he develops the obstacle-belt design.

Maximize Subordinate Flexibility

Designing obstacle belts is a balancing act between providing maximum flexibility and focusing tactical-obstacle employment for the subordinate maneuver commander. Maneuver battalions are normally given sectors to defeat the attacking enemy but may be given a BP or strongpoint. The BP and strongpoint are examples of restrictive control measures. Defending in sectors gives the battalion commanders the freedom to maneuver and also decentralizes fire planning, whereas the BP dictates where the majority of the battalion's combat power must be positioned. Even with the more restrictive control measures, battalions still require flexibility in tactical-obstacle employment. The strongpoint is the most restrictive control measure; obstacle-belt flexibility is greatly reduced and focused.

The brigade engineer provides the required flexibility with obstacle-belt graphics through two dimensions: width and depth. The obstacle belt permits the battalion commander to employ tactical obstacles to complement his fire planning and his allocation of maneuver companies, whether in sector or BP. The maneuver battalion is normally assigned a sector or BP based on the attacking enemy's combat power along a specific AA. At a bare minimum, the assigned obstacle belt must encompass the AAs. The maximum flexibility for an obstacle belt width is the entire subordinate's sector. Two exceptions for not providing this flexibility are facilitating future operations and identifying severely restricted terrain, which prevents the enemy from maneuvering. Care must be taken when identifying severely restricted terrain as to its applicability for mounted or dismounted maneuver.

The depth of the obstacle belt is tailored to the brigade's scheme of maneuver and the commander's intent. Specific phase lines (PLs) normally aid in tailoring the depth of the obstacle belt. For example, one battalion might be given the mission to defend well forward in the sector. The obstacle belt would facilitate this intent by allowing less depth. Typical graphics that aid in focusing the depth of an obstacle belt are--

• On-order boundary changes.
• Battle handover lines (BHLs).
• Rear boundaries.
• Forward edges of the battle area (FEBAs).
• Lines of departure.
• Fire-control lines.
• No-fire areas.
• Coordinated fire lines.
• Passage lanes and corridors.
• PLs controlling friendly force positioning.

Facilitate Future Operations

To facilitate future operations, the brigade engineer uses obstacle belts as a restriction of tactical-obstacle employment. The brigade's need for future mobility drives the need for tactical-obstacle restriction. The restrictions fall into two categories:

Decreasing Flexibility. This involves reducing the size of individual belts. Shaping obstacle belts so that they do not overlap the routes needed for future operations ensures freedom of movement.

Restricting Obstacles. This limits the employment of obstacles. Typical examples are allowing surface-laid mines only, restricting the use of antihandling devices, and specifying a no-later-than self-destruct time for SCATMINEs. These obstacle restrictions facilitate future occupation and obstacle clearance by friendly forces.

OBSTACLE PLANNING

Obstacle planning is organic to the brigade's military decision-making process. Its goal is obstacle integration into the commander's intent for the operation and the scheme of maneuver. Obstacle planning must remain flexible to accommodate changes during the planning and the subsequent preparation for the execution of the defense.

Although this chapter focuses on obstacle planning for the defense; the process can be equally applied to offensive operations.

Obstacle-Planning Steps

The echelons of obstacle-planning and obstacle-control principles provide the foundation for the obstacle-planning process. The brigade engineer and brigade staff plan obstacle-control measures to control and focus obstacle effort for subordinate units. Like the engineer estimate, obstacle-planning steps are conducted concurrently as the scheme of maneuver is developed. The obstacle-planning steps are--

• Situation analysis.
• Organization of the operation.
• Mobility and future operations requirements.
• Obstacle resourcing.
• Scheme-of-obstacles overlay.

Of the five obstacle-planning steps, obstacle resourcing is the only one that will be discussed.

Figure 4-4 shows the components of the obstacle-planning process as a parallel process to the military decision-making process. Figure 4-5 provides details on the obstacle planning process.

Obstacle Resourcing

There are two techniques that the brigade engineer and staff use for estimating resource requirements for obstacle-control measures. They are--

• Requirement-based resourcing.
• Capability-based resourcing.

For more information on these techniques, tentatively array obstacle groups against see FM 90-7, Appendix C.

Requirement-Based Resourcing. One technique is for the brigade to develop tentative obstacle-control measures one level down (battalion), group the control measures into a higher control measure, and resource the higher control measure based on the projected subordinate control measures. For example, the brigade would tentatively arrayed companies in the scheme of maneuver, combine the groups into belts, and resource the belts with obstacle capability based on the tentative groups.

Capability-Based Resourcing. Another technique available to the brigade engineer and staff is to develop the obstacle-control measure based on the scheme of maneuver and resource the obstacle-control measure with obstacle capability based on the main effort, priorities, and task organization.

SURVIVABILITY PLANNING

The brigade commander establishes his survivability intent for critical weapons, vehicles, and positions within the brigade. This intent is analyzed by the brigade engineer during the engineer estimate process. The brigade engineer determines the number and type of positions needed to meet the commander's intent. Frequently, at brigade level, this process is used to allocate survivability resources to the battalions rather than to individual systems. During the estimate process, this allocation is balanced with countermobility requirements that may cause problems with the two missions competing for the same equipment resource. Exceptions to resource allocation occur when the brigade commander establishes a strongpoint or an armored unit under brigade control. In these cases, the brigade engineer normally determines BP/EA survivability priorities.

A planning technique that can be used is through aligning the commander's obstacle effects against survivability requirements to conduct initial survivability resourcing. Figure 4-6 shows an example of this method using a tube-launched, optically tracked, wire-guided (TOW) AT missile launcher mounted on high mobility, multipurpose wheeled vehicles (HMMWVs) for position estimates. The survivability levels shown in this figure are not fixed and are only shown as an example. It is the commander's decision (based on METT-T, balanced against desired obstacle effects) that drives the different survivability levels. In the end, it is the brigade engineer's responsibility to deconflict any potential resourcing problems for the battalions when countermobility requirements of assigned belts conflict with the brigade-directed survivability levels.

BATTLEFIELD FRAMEWORK

Brigades may perform a variety of missions within the battlefield framework. Normally, brigades defend within the MBA or serve as a division reserve. The battlefield framework consists of--

• Deep operations.
• Security operations.
• MBA operations.
• Rear operations.
• Reserve operations.

DEEP OPERATIONS

Deep operations support the commander's basic scheme of maneuver by conducting operations against the enemy in depth. Light engineers can be used to conduct cross forward line of own troops (FLOT) reconnaissance and engineer raids. Light engineer missions prevent the enemy from concentrating overwhelming power against the brigade's MBA forces. They accomplish this by separating the enemy's echelons and disrupting its command, CS, CSS, and LOC. Effective execution depends on careful planning and the IPB. Air-assault units are particularly suitable for this type of operation.

SECURITY OPERATIONS

Security operations are essential to the success of the brigade defense. They are characterized by aggressive reconnaissance to reduce terrain and enemy unknowns. This is achieved by gaining and maintaining contact with the enemy. Engineers have the ability to upgrade routes and survivability. They should not be used to construct protective obstacles. All combat units have this task as part of their mission.

MBA OPERATIONS

Forces at the FEBA, or within the MBA, fight the decisive defensive battle. The forces are positioned so that they can control or repel enemy penetration. The brigade commander adjusts the initial defensive plan based on information received during security operations. He assigns the battalion sectors, BPs, strongpoints, or a combination of all three based on METT-T. They usually coincide with a major AA. Engineers put in obstacles based on the desired effect:

• Disrupt.
• Turn.
• Fix.
• Block.

Engineers should also be ready to support the counterattack. The brigade commander and staff must recognize the likelihood of penetrations of the MBA when they are fighting a large mobile force. When this occurs, engineers should be deployed to that area.

REAR OPERATIONS

Corps and division commanders normally direct rear operations, although the brigade's tactical operation may include rear operations. When this occurs, engineers could be called on to--

• Upgrade/repair MSRs.
• Repair FLSs.
• Perform survivability missions.
• Build FARPs.

Corps engineer assets are usually requested to perform these missions.

RESERVE OPERATIONS

Reserve forces in the defense preserve flexibility. Engineers can be used to support counterattacks by performing mobility missions, reinforcing forward defensive positions to block enemy forces that penetrate the brigade's defense, or reacting to a rear-area threat.

LIGHT BRIGADE DEFENSIVE OPERATIONS

The principles and considerations presented at the beginning of this chapter are relevant to all types of "light force" defensive operations (airborne, air assault, light). Defensive preparations for a light brigade (especially when defending against a force of greater mobility and firepower) require EAD engineer support beyond that which can be provided by task-organized DIVENs.

BRIGADE SCENARIO

The division commander has positioned the brigade in an economy-of-force mission in restrictive terrain. The brigade has been given the mission to defend in sector, denying the enemy use of multiple high-speed AAs into the division and joint task-force (JTF) rear. The brigade sector is composed of very restrictive terrain with two battalion-sized MCs that will support a mounted attack. Enemy forces facing the brigade are a motorized rifle regiment (MRR) variant with two MRBs and one light dismounted battalion. Enemy forces have the mission to attack and destroy the division lodgment (rear). Figure 4-7 shows the brigade scheme of maneuver.

The brigade's combat power consists of its three organic infantry battalions, in addition to combat units task-organized to the brigade. These units could include--

• A task-organized aviation TF.
• An M8 light tank company.
• Other supporting units.

Engineer assets task-organized to the brigade are a--

• Light DIVEN company (augmented by a division assault and barrier (A& B) platoon slice).
• Corps light engineer company.
• Combat support equipment (CSE) horizontal platoon.

This level of engineer support for a light brigade will take the existing engineer C2 system to its operational limits. Without the total synchronization and integration of all engineer forces in the brigade sector, engineer support to the brigade is at risk. Any higher density of engineer support to the brigade requires that a C2 package be established and task-organized to the brigade by the DIVEN. After the light DIVEN company deploys into the operational area, it is task-organized to the brigade. It augments the engineer C2 system and establishes the BREC. The corps light engineer company ties into the established engineer C2 system and augments existing C2 systems capabilities. The brigade engineer retains functional control, through the brigade commander, of all engineer forces in the brigade sector. The company commanders maintain unit C2 of their companies and any additional forces task-organized to them.

BRIGADE SCHEME OF MANEUVER

The brigade will conduct the operation in the following:

• Phase 1-Preparation and countereconnaissance.
• Phase 2-Security area battle.
• Phase 3-MBA battle.

1st Battalion

The battalion defends in the sector forward of PL Black, allowing no penetration larger than a company (-); conducts battle handover early with the aviation TF well forward of the BHL, PL Green; and prepares to receive support from the light tank company.

2d Battalion

The battalion defends in the sector forward of PL Black, allowing no penetration larger than a company (-); conducts battle handover with the aviation TF at PL Green; receives OPCON of the light tank company (on order, the light tank company is OPCON to the 3d battalion); and is the brigade's main effort during phase 2.

3d Battalion

The battalion defends in the sector forward of PL Gold (brigade's no-penetration line) against remaining enemy forces; does not allow enemy penetration of PL Gold by platoon-sized or larger elements; on order, receives OPCON of the light tank company from the 2d battalion; establishes company-sized elements as the brigade reserve; prepares to support the forward battalions by air assault; and is the brigade's main effort during phase 3.

Aviation TF Commander

The commander initially screens along PL White; conducts battle handover with the division cavalry troop; destroys enemy reconnaissance assets and identifies the main body; performs the guard force mission with the priority to destroy enemy C2 and breaching equipment upon contact with the main body; on order, conducts battle handover with the 1st and 2d battalions; prepares to support the 1st, 2d, and 3d battalions with attack helicopter (AH) support; and assumes the brigade reserve after battle handover.

Light Tank Company

The company defends in the sector; initially is OPCON to the 2d battalion; assists the security area fight by providing fires into EA Club; on order, is OPCON to the 3d battalion; and prepares to support the 1st battalion.

DEEP OPERATIONS

The division is conducting all operations forward of the FLOT. PL White is also the division's fire-support coordination line. Vital information (enemy's formation and composition) will be passed from the cavalry squadron to the brigade. This will aid in high-payoff target nominations and selections for the attack helicopter battalion (AHB) in the security area fight. The brigade engineer must also receive any information relating to planned obstacle zones or belts employed forward of the brigade sector that will be used during division security operations. This will facilitate the integration of planned obstacle intents between the division and the brigade and the transition from division security operations to brigade security operations. Figure 4-8 shows some mission considerations for brigade deep operations.

SECURITY OPERATIONS

Security operations are characterized by reconnoitering aggressively to reduce terrain and enemy unknowns. This is achieved by gaining and maintaining contact with the enemy to ensure continuous information and by providing early and accurate reporting of information to the main body.

The aviation TF is the security force for the brigade (see Figure 4-9). Their mission is to--

• Initially screen along PL White.
• Conduct battle handover with the division.
• Destroy enemy reconnaissance forces.

The security-area fight for this operation will be characterized by the following:

• Centralized planning.
• Decentralized execution.
• Rapidly developing fight.

To accomplish its missions, the aviation TF must have security-area forces in position as soon as possible. To provide the maximum amount of support for the security-area fight, planning is conducted centrally by the brigade with the aviation TF commander and staff. Only after planning is completed (as an extension of the estimate process) can the early initiation and completion of work in the security area begin. This planning ensures that the aviation TF commander has the maximum latitude for execution and yet is in agreement with the brigade commander's intent and concept of the operation. This planning also ensures that the execution of missions in support of the security-area battle can begin before the brigade OPORD is issued or soon after.

The brigade will take control of the battle from the division, with an air cavalry troop screening for the brigade. Upon contact with the attacking first echelon, the aviation TF commander will assume the guard force mission, committing his attack assets in conjunction with both indirect fires and tactical, air sorties. With the main effort of enemy effort templated to be in the southern sector, the aviation TF will conduct battle handover early with the 1st battalion in the north. This will allow the aviation TF to focus its antiarmor efforts on EA Diamond and EA Club.

Integrated delay actions are planned in the southern portion of the security area. The light tank company (-) will position forward of the FEBA (PL Red) and behind PL Green to fire into EA Club. Once the light tank company (-) initiates fires into EA Club, attack elements of the aviation TF will engage the enemy from the flanks and rear, allowing the light tank company (-) to displace to its subsequent position. The brigade engineer and the supporting company commanders must fully understand the significance and the intent of the aviation TF's screen mission and its transition to the guard force. Because of the importance of timely and synchronized engineer support, an engineer planner is sent to the aviation TF's CP.

A combined ground and aerial reconnaissance by company commanders and key security-force leaders is critical to effective engineer support in the security area. The execution of engineer missions supporting the security-area fight must begin early so that engineer forces working in the security area do not impact MBA preparations. Figure 4-10 shows both light engineer companies task-organized to the brigade and working in the security area. When the MBA TFs are ready to begin their planning process, an engineer planner (from the company that will be supporting that battalion during MBA preparation) is sent to the TF CP. Engineer forces are then echeloned into the MBA preparation as security-area preparation is complete and MBA TF missions are available.

The brigade commander's early commitment of the majority of his engineer forces will require detailed coordination for their security. Enemy forces will frequently target friendly engineer forces and Class IV/Class V supply points. This is especially true-for a light force defending in restrictive terrain where obstacles can have a significant impact on the enemy's maneuver. The brigade engineer coordinates security requirements for engineer forces to provide protection from both ground and air threats. He also coordinates with the brigade air defense artillery officer (ADAO), ensuring that the air defense artillery (ADA) weapons coverage plan is synchronized with the engineer work plan. To effect adequate coverage, stinger teams may be required to link up with and deploy into the security area with engineer forces. The brigade engineer also coordinates with the brigade S3 for ground security. Coordination with the aviation TF commander may also allow ground security from the aviation TF ground cavalry troop. A ground-defense plan must also be addressed by the company commanders, encompassing protection against any templated ground threat during the preparation phase.

Obstacle belts established to support security operations must facilitate decentralized combat operations. While one belt could have been established for the entire security area, two were developed to facilitate resourcing. Belt Al encompasses EAs Heart and Diamond, and belt A2 includes EA Club. One of the first steps taken by the brigade engineer is to verify with the division any obstacle restrictions linked to the division's fire support coordination line (FSCL) (PL White). In this example, the ability to engage targets forward of PL White would facilitate the brigade's acceptance of the fight from the division. Once the sites for obstacle belts Al and A2 (forward of PL White) have been approved by the division, plans are made by the brigade engineer, company commanders, the brigade aviation LO, and TF staff for the aviation TF to employ three disrupt obstacle groups (point obstacles) within each belt. While these groups are not normally dictated to the aviation TF, they might be in this situation to help in quickly assuming control of the security area. The initial location of the groups is a result of careful and detailed analysis of METT-T, reinforced by reconnaissance. It is detailed enough to preclude any significant changes in the intent and location of the groups. The groups are designed to facilitate the aviation TF's ability to gain early contact with the enemy and to maintain pressure on it through the security-area fight. Group planning is also vital to support initial logistics and engineer resourcing for the belts. Conventional obstacles, along with air and ground Volcano, MOPMS, ADAMs and RAMMs, can all be resourced for these belts.

Detailed planning conducted at the brigade and subsequently with the aviation TF may allow lift assets to haul and place Class IV/Class V (obstacle) supplies at obstacle-group locations. These same lift assets may also be able to sling engineer equipment forward, as required. The aviation TFs have two primary missions during phase 1. They are--

• Early warning of the main body.
• Destruction of enemy reconnaissance forces.

For a light force, the destruction of enemy reconnaissance elements is especially critical. Such destruction significantly degrades the enemy's ability to develop an accurate picture of the MBA. The aviation TF's initial obstacles should focus on the destruction of enemy elements and, ultimately, the disruption of the its lead echelons. Detailed ground and air reconnaissance, detailed obstacle planning conducted at the brigade, and the S2's templating of the enemy's reconnaissance and first-echelon elements aid in the final positioning of obstacles. Initial engineer effort is directed at supporting the counterreconnaissance fight. This effort can consist of point obstacles integrated with remote-sensor devices from military intelligence assets available in the brigade. These obstacles serve to destroy enemy reconnaissance elements and provide early warning to the aviation TF of its presence in the brigade's sector, allowing AHs to quickly respond.

M/S responsibilities in the security area also encompass elements of the light tank company. The brigade commander directs two platoons of the light tank company to be positioned just forward of the FEBA (in the 2d battalion's sector), controlling PL Green and the BHL for the 2d battalion. They will engage enemy targets in belt A2 (EA Club) and then disengage to subsequent positions in the 2d battalion's sector. Obstacles in belt A2 must not only enhance indirect fires and AH fires but also main-gun fires from the light tank platoons. Integrating these three levels of fires with the desired obstacle effects in restrictive terrain is ultimately the responsibility of the aviation TF commander. It requires detailed coordination between the aviation TF commander, the light tank company commander, the brigade engineer, and the supporting company commander. The plan is for the light tank platoons to fire into EA Club at the enemy's first-echelon elements. The aviation TF's AHs then use their combat power to distract and disrupt the attack so the light tank platoons can disengage and displace to subsequent positions. The brigade engineer and the aviation TF commander consider situational obstacles in belt A2 to assist the light tank platoon and aviation TF in providing time and space for the battle handover with the 2d battalion.

The brigade commander wants turret-defilade positions for the two light tank platoons to ensure their survivability for the MBA fight. Figure 4-11 shows some mission considerations for security operations.

MBA AND RESERVE OPERATIONS

The decisive battle to defeat the enemy will be fought in the MBA (see Figure 4-12). Forces are positioned in the MBA so that they can control or repel enemy penetrations. The brigade engineer and company commanders dedicate the majority of their planning time to the MBA fight. Each of the three battalions require different engineer planning and execution considerations.

1st Battalion

The 1st battalion's area is characterized by restrictive terrain with two company-sized mounted MCs that converge at about the midpoint of the sector into a single battalion-sized corridor. The primary concern for the battalion is the templated MRB, primarily BMP-1s, moving through its sector and into the brigade rear.

The 1st battalion commander will conduct a defense in the sector, exercising the option to begin his engagement of enemy forces at long range. The battalion will accept early battle handover with the aviation TF well forward of the BHL (PL Green). EA Heart and EA Diamond are designed to facilitate the BHL. An AH and indirect and tactical-air fires will initially service the EAs. These fires are intended to breakup the continuity of the enemy attack as it approaches the BHL. As the aviation TF assets conduct battle handover with the 1st battalion and shift its efforts to the south, indirect and tactical-air fires continue into the two EAs. As the enemy moves within range of the battalion's heavy antiarmor weapons (TOW AT missile launchers mounted on HMMWVs) at the western edge of the two EAs, these weapons further disrupt the enemy's synchronization, keying on HVTs. As the enemy approaches the BHL where the terrain splits the sector into two company-sized mounted MCs, the TOW AT missile launchers disengage to subsequent positions. When the enemy is within range of the battalion's organic weapons systems, antiarmor weapons engage it from multiple directions. Finally, as the enemy enters EA Jack, all the battalion's antiarmor systems are directed at the destruction of the enemy, with AHs from the aviation TF on call.

A corps light engineer company, given the mission of emplacing belt Al in the security area, is task-organized in DS to the 1st battalion. This allows the corps light engineer company commander to provide the 1st battalion with detailed information on the terrain, the obstacles, and the plan for conducting the security-area fight immediately forward of the battalion. This task organization is effective when the corps light engineer company's work in the security area is completed.

The planning and execution of engineer operations in support of the 1st battalion are facilitated through the company commander that is task-organized to the battalion involved in the planning process at the brigade. This allows his company to remain proactive to the entire operation, especially during the company's transition from supporting operations in the security area to supporting the 1st battalion in the MBA. While the company is conducting operations in belt Al, the 1st battalion will begin planning for their defense in the sector. The company commander is responsible for sending an engineer planner to the 1st battalion CP during its planning. It is preferable for the company commander to conduct this planning. However, many factors help determine who is actually sent, such as the--

• Current status of engineer work in belt Al.
• Current enemy situation in the brigade sector.
• Fact that the predominance of engineer effort will be expended in the MBA where the decisive battle will be fought.

As the plan develops and engineer missions are generated, engineer elements are echeloned out of the security area into the 1st battalion's sector to begin work. This transition is monitored closely by the company commander to ensure the completion of work in the security area and the rapid shift of engineer effort into the 1st battalion's sector. The current status of the transition must be reported to the brigade engineer.

A detailed terrain analysis by engineer planners and executors is critical to the 1st battalion's defense. This analysis will influence two key elements of engineer support:

• Obstacle-belt location (and intent).
• Engineer resource allocation.

An important component to the terrain analysis is the detailed information on the terrain and obstacles in the security area forward of the 1st battalion's sector. This information is important to the commander. It allows him to know how the enemy's maneuver will be affected before entering the MBA. The corps engineer company commander is the main source for this information.

The brigade engineer and the company commanders develop two belts to support the 1st battalion. A disrupt belt (B1) and a fix belt (B2) were developed using the requirement-based technique. Groups were planned through the war-gaming process to determine the components of the belts, but the groups were not dictated to the battalion. Figures 4-13, and 4-14 show obstacle belts and defensive considerations for the 1st battalion.

Engineer planners developed belt B1 in anticipation of the battalion employing two disrupt groups. These groups are aimed at breaking up the enemy's C2 and forcing it to piecemeal its attack. The locations of the group are tied to the terrain where the enemy's maneuver formations will be forced into company MCs. These groups are also intended to support early battle handover with the aviation TF and to initiate the battalion's long-range fires in and around the area where its TOW AT missile launchers can effectively engage.

The fix belt (B2) is resourced for three fix groups. These fix groups are aimed at holding the enemy in the narrow portions of the MCs and in EA Jack, forcing it to breach repeatedly. This significantly slows the enemy's mounted movement. The groups are also balanced against the antiarmor capabilities of the battalion in that portion of the sector. This enhances the tracking time available to and the maximum standoff range of the weapons systems.

Battle handover will occur first with the 1st battalion. To facilitate this, the 1st battalion must receive detailed information on the terrain and obstacles in the security area forward of its sector. This information is vital to allow for an early, seamless transition of the fight from the aviation TF to the 1st battalion. This information also allows the battalion commander to understand what impact it will have on his defensive sector. The corps light engineer company supporting the 1st battalion is the base for this information. During war gaming with the brigade staff, the engineer planners determine that the battalion's TOW AT missile launchers can effectively engage targets in the two westerly groups planned in belt Al. The decision on whether the battalion commander uses these groups to facilitate the early battle handover will be his to make, but guidance is issued in the brigade order. However, the disrupt groups in belt B1 are planned to support and synchronize defensive measures with the two adjacent groups in belt Al.

Engineer planners direct their efforts at the mounted enemy coming into the 1st battalion's sector, but they are also alert to the possibility of a dismounted enemy coming into the sector using the restrictive terrain. Initial planning is conducted, and assets are resourced by the brigade to assist the battalion in countering the enemy. Detailed planning will be conducted by the corps light engineer company commander with the battalion during its planning process.

Survivability efforts must begin in the sector as soon as possible due to the enemy's templated indirect-fire capabilities. Since all engineer equipment will not be required to support security-area preparation, some can be echeloned to the battalion's sector early and begin work on battalion assets in position.

Protective-obstacle effort by the maneuver forces is also vital, especially around EA Jack. Because the battle will be conducted at close range (combined with the brigade commander's concept of the operation around EA Jack), the likelihood of an enemy dismounted attack to eliminate the antiarmor BPs is very strong. The brigade engineer and the company commanders address this Class IV/Class V (obstacle) requirement and plan resources accordingly. Care is taken to ensure that those materials required for protective-obstacle effort do not compete for resources allocated to tactical obstacles. Guidance is issued in the brigade order, as required, to control these resources.

Mobility support is directed at providing egress routes for the TOW AT missile launchers mounted on HMMWVs to allow them to move to subsequent positions. The light tank company has a be-prepared mission to provide support to the 1st battalion.

2d Battalion

The 2d battalion is positioned in the enemy's templated main effort in the southern portion of the brigade's sector. This sector is characterized by a battalion-sized mounted MC in the north and a battalion-sized dismounted AA in the south. Cross-country movement of tracked or wheeled vehicles in the dismounted AA is restricted to a very limited trail network. It is templated that a dismounted supporting attack will use this AA to attack antiarmor positions in the 2d battalion's sector and to secure the choke point in the 3d battalion's sector. A detailed terrain analysis. verified by ground and air reconnaissance, is fundamental to maximize engineer effort in the 2d battalion's sector.

War gaming with the brigade staff reveals that the battalion will most likely conduct a defense in the sector against both the mounted and dismounted enemy. The defense against these two types of enemy forces will require significant, yet varied, levels of engineer support. One DIVEN company with A& O platoon assets will support the 2d battalion (see Figure 4-14).

Engineer support will begin early in the security area forward of the 2d battalion's sector in and around belt A2, paralleling the efforts of the corps light engineer company in the north. This support will be executed by the light DIVEN company. When the 2d battalion begins its planning process, the company commander is responsible for providing an engineer planner to integrate with the battalion staff. The company commander normally fulfills this responsibility (METT-T dependent).

To augment the combat power of the battalion against the mounted enemy, the brigade commander task-organizes the light tank company OPCON to the battalion. During the security-area battle, two platoons of the light tank company will be placed in a position to control PL Green and will be cleared to fire into the westerly disrupt group of belt A2. Their direct fire must be synchronized with the AH fires from the aviation TF. This is the responsibility of the aviation TF commander. However, it is facilitated through the efforts of the light DIVEN company commander and the light tank company commander during the brigade planning process and during actual obstacle emplacement.

Because of the two types of enemy in this sector, engineer planners at the brigade develop four belts. Two of the belts are focused and resourced against the mounted enemy, and two are focused and resourced against the dismounted enemy infiltration.

Belt B3 is resourced for two disrupt groups. Its intent is to--

• Ensure that the enemy's mounted formations deploy before entering the MBA
• Allow initial flank-and-rear antiarmor engagements from the battalion.

Belt B3 is also positioned to facilitate the seamless transition of forces from the security-area battle to the MBA.

Belt B4 is resourced for two fix groups and a turn group. Its intent is to turn and hold the enemy force in EA Queen. This can enhance the fires of both light tank companies--

• From their subsequent positions.
• From the battalions' antiarmor BPs located in restrictive terrain around EA Queen.

The dismounted enemy's infiltration will probably begin early to synchronize its attacks with the mounted enemy's attacks within the MBA. Identifying and gaining contact with the dismounted enemy's infiltration early (forward of PL Green), and disrupting the timing of its attacks with the timing of the mounted enemy's attacks, is vital to the 2d battalion's defense. Through guidance issued in the brigade order and the brigade commander's approval of positioning belt B5 forward of PL Green, the battalion will be able to gain early contact with the dismounted enemy while it is still in the security area. The battalion conducts extensive counterreconnaissance and uses combat patrols (closely linked to AP obstacles), early warning devices, and limited visibility devices to gain early contact with the enemy and to destroy them.

Belt B5 is resourced for two fix groups and one turn group. The initial fix group is planned to allow the battalion to hold the enemy in order to establish a tactical advantage and to allow for an air-assault HATK using lift assets from the aviation TF. When executed, these actions disrupt the timing of the dismounted enemy's attack. This allows the battalion to focus its efforts and resources separately and fighting the two different enemies simultaneously. The turn group is planned to isolate antiarmor BPs from the dismounted enemy, while the second fix group has the same purpose as the first and acts as its extension. Situational obstacles are also planned within belt B5 to assist in rapidly developing a very decentralized battle. These obstacles are primarily AP SCATMINEs (ADAM and Volcano AT and AP mix). The execution of situational obstacles is closely linked to the--

• Decision points verified by the battalion's extensive counterreconnaissance efforts.
• Execution timings rehearsed by the battalion.

The brigade engineer's major concern while light DIVENs establish obstacle belt B5 (forward of PL Green) will be fratricide deconfliction with both indirect and AH fires. Extensive coordination, initiated, directed, and monitored by the brigade, between the 2d battalion and the aviation TF must be conducted to minimize fratricide risks. The brigade engineer ensures that some AT obstacles are resourced (predominantly point type) to allow the engineers to restrict mounted movement on trails in the belt.

Belt B6 is resourced for two fix groups, a turn group, and a block group. Belt B6 was developed as a separate belt from B5 for three principal reasons:

• It was war-gamed that the operational tactics by the battalion will be closely linked to the terrain, specifically terrain features to the south of EA Queen.
• The dismounted AA is constrained forward of PL Orange, possibly impacting the maneuver formations of the enemy force.
• Initial resourcing and positioning of Class IV/Class V supply points in the battalion sector was simplified by the establishment of the separate belt.

The turn and block groups planned for belt B6 are of key importance to the brigade. The turn group is directed at denying the dismounted enemy access to the light tank company's subsequent positions forward of PL Black. The block group is aimed at denying enemy penetration into the 3d battalion's sector. To ensure synchronization and integrity of the obstacle belts and the maneuver plan, the brigade engineer conducts detailed coordination with his counterpart in the southern brigade. This validates the commander's intent and concept of the operation, helping to ensure that the two brigades are complementing each other's efforts. This coordination may be directed by the DIVEN.

Survivability support for the 2d battalion must be initiated early, with assets from the attached A& O platoon constructing turret-defilade positions for the two light tank platoons forward of PL Red. The initial positioning of these elements is directed by the brigade; therefore, this work can begin parallel to the engineer company's effort in the security area. Coordination as to the actual location and status of survivability work for the light tank platoons will be conducted with the 2d battalion. Survivability work in support of the light tank company's subsequent positions in the sector must begin as early as possible. This depends on guidance from the battalion commander. The battalion may also choose to position its TOW AT missile launchers mounted on HMMWVs forward as well, allowing them to dig in at the same time. Survivability support for the antiarmor BPs will also be extensive. Because the antiarmor BPs are positioned along the enemy's AA, they must be prepared with sufficient survivability efforts to survive significant enemy preparatory indirect fires. To provide additional survivability support, the corps light engineer company commander is issued a be-prepared order to provide additional blade teams (from the OPCON CSE platoon) to support the 2d battalion. Protective obstacles are emplaced by the maneuver forces around the antiarmor BPs primarily along the dismounted AA. Protective-obstacle resourcing is initially done by the brigade engineer. Modifications to his estimates are completed by the TF engineer in conjunction with the 2d battalion support platoon leader, as required. These efforts will be substantial as they must protect against the possible infiltration attack and expected dismounted assaults from the BMP battalions around EA Queen.

Mobility support will be centered on the ability of the light tank company and the TOW AT missile launchers mounted on HMMWVs to displace to subsequent positions throughout the battalion's sector. In addition to its move from forward of the BHL to its subsequent position in the battalion's sector after battle handover (Lane Lion), the light tank company will move on order back to the 3d battalion (Lane Tiger). It also has a be-prepared mission to support the 1st battalion (Lane Bear). Lane closure and marking and identification procedures should be initiated by the brigade to ensure consistency throughout its sector. The brigade engineer must ensure that detailed coordination (in reference to lane status) occurs between the three battalions and the light tank company commander as they cross battalion boundaries.

3d Battalion

The 3d battalion is positioned to the rear of the 1st and 2d battalions. Its focus is on denying the enemy the high-speed AA into the brigade rear. The 3d battalion's sector is characterized by a mounted battalion (+) sized AA in the north that passes through a choke point in the depth of the sector. The southern portion of the sector consists of very rugged and restrictive terrain that supports a dismounted AA of at least battalion strength. It is templated that surviving enemy forces from both the 1st and 2d battalion's fight will attack to secure this choke point. The light tank company, along with AHs from the aviation TF, will be available to the 3d battalion for the fight. The CSE platoon (less its road graders) is task-organized to support the 3d battalion from the beginning of the operation. The CSE platoon remains under brigade control.

War gaming by the brigade staff shows that the combination of the terrain, the brigade commander's mission for the 3d battalion, and the establishment of the no-penetration line supports a strongpoint-type defense around the choke point. The brigade engineer and the other engineer planners realize that a significant amount of manpower, time, and assets must be expended for this type of defense. Early and detailed estimates for Class IV/Class V supplies and engineer assets are critical to the operation. The resources must be closely monitored by the brigade engineer to ensure that critical time and effort are not lost. As engineer assets are available from the 1st and 2d battalion's sectors (and on order from the brigade commander), they will be echeloned into the sector to begin work.

Planning and work by the 3d battalion must begin as early as possible. The brigade engineer must decide early in the brigade planning process who will--

• Provide the 3d battalion staff engineer input during planning.
• Have overall execution responsibility for engineer efforts.

In this scenario, it is war-gamed that the corps light engineer company will complete its efforts in the 1st battalion's sector first. Another key factor is that the battalion commander and the supporting engineer unit commander(s) must conduct a ground reconnaissance. This is important so that work priorities can be established within all sectors. The first priority is to make the position impassible to mounted forces. The second priority is to protect the battalion's antiarmor positions from a dismounted attack. The third priority is to protect the infantry forces that are guarding the antiarmor weapons.

Engineer planners at the brigade developed and resourced two block belts in support of the 3d battalion's defense (see Figure 4-14). Because of the no-penetration line established by the brigade, the intent of belts D1 and D2 may be dictated by the brigade commander. Belt D1 is resourced for two fix groups and one block group. Its focus is on an enemy mounted attack. Belt D1 is positioned to facilitate the transition of the MBA fight to the 3d battalion. It is aimed at initially fixing the enemy's mounted formations in EA King and then at blocking enemy formations forward of the choke point and PL Gold (the brigade's no-penetration line).

To facilitate the transition of the fight between the battalions, an engineer-specific contact point is established at the common boundary of the three battalions. Figure 4-13 shows this contact point. By establishing a contact point, the brigade engineer can ensure that the battalion's TF engineers have coordinated and synchronized their efforts, especially in the area where the two main enemy AAs merge. Specific requirements for the time and type of information to be transferred at the contact point are outlined in the engineer annex.

Belt D2 is resourced for a turn and a block group. It is focused on the dismounted enemy coming from belt B6. Similar to belts B5 and B6 in the 2d battalion's sector, the turn group's objective is to isolate the antiarmor systems in and around the choke point from the dismounted enemy. Contact with the dismounted enemy must be established early around PL Black, and engineer efforts in belt D2 must facilitate this. The dismounted enemy must not be allowed to get behind the 3d battalion's forces at the choke point if PL Gold is to remain intact. To enhance the effectiveness of belt D2, detailed terrain and obstacle information and its potential impact on the dismounted enemy must be passed from the 2d battalion's TF engineers to the 3d battalion's TF engineers.

Survivability support for the 3d battalion will be the most intense in the brigade sector and must begin early to ensure that a sufficient level of protection is achieved. The choke point and the positions controlling it will receive intensive artillery attacks. Therefore, survivability must be ensured for C2 nodes, crew-served weapons, antiarmor weapons, and the light tank company. To support the block intent established by the brigade commander, turret-defilade positions are required for the light tank company and the TOW AT missile launcher mounted on HMMWVs. This level of survivability will require early coordination with the 3d battalion's TF engineers, the battalion commander, and the light tank company commander. Dismounted attacks are templated to be intense and frequent as the enemy attempts to gain control of the choke point. Protective obstacles constructed by maneuver forces around the antiarmor BPs and any positions established on the dismounted AAs in belt D2 will be critical. Engineer planners at the brigade will conduct the initial resourcing for this effort early, ensuring that tactical and protective-obstacle efforts do not create resourcing conflicts.

Mobility support will again focus on the light tank company that will be supporting the 3d battalion when it falls back to its subsequent positions. Lane-closure plans and information on the status of lanes Tiger and Bear will be exchanged at the engineer contact point. Because the light tank company will be moving into the 3d battalion's sector during the MBA fight, lane closures affecting its displacement may require brigade control. Lane closure also affects the light tank company's mobile reserve mission. The reserve force is usually held back until the enemy has committed itself and has become disrupted and extended. The brigade commander determines when to commit the reserve forces. This commitment will require that the light tank company be able to rapidly move to any of the three battalion's sectors. The brigade engineer is ultimately responsible for monitoring the lane-closure plan and must work closely with the TF engineers and the light tank company commander to ensure successful execution. Engineer involvement in the combined arms rehearsals for the light tank company's movement on the battlefield is vital.

From an engineer standpoint, the reserve force must survive long enough to become committed. Once the reserve force is committed, it must have the mobility to perform its counterattack. This may require some survivability support initially and then some mobility support in the form of improving combat trails, ford sites, and so forth. During the preparation of the battlefield, flank obstacles can be emplaced or situational obstacles can be planned to support the counterattacking force if the counterattack route is known. This requires that the brigade engineer conduct extensive coordination with the reserve force to prevent fratricide and to ensure that its mobility is not affected. Figure 4-15 shows some mission considerations for MBA defensive operations.

REAR OPERATIONS

The objective of rear-area operations is to ensure that maneuver units receive continuous support from the support units of the brigade (see Figure 4-16). These operations consist of force protection and area damage control (ADC) actions that are taken by all combat, CS, CSS, and HN units. They work singly or in a combined effort to secure the force or to neutralize or defeat enemy operations in the rear area. Rear-area operations represent a critical fight for the brigade commander and the brigade engineer. DIVENs are not equipped to handle the diverse, equipment-intensive tasks involved in rear operations. Therefore, the light infantry brigade relies heavily on corps support for general engineering in the brigade rear.

In this scenario, the light DIVEN company has established the BREC in the brigade rear, and it is tied in to the brigade rear CP (see Figure 4-17). The corps light engineer company ties in with the established BREC. It augments the BREC's capability to monitor, track, and control engineer support to the brigade rear and monitor and track engineer support in the MBA. The collocation of the two company CPs greatly enhances this capability. The brigade engineer assigns the CSE platoon the missions of maintaining the LOC (within the brigade rear and to the battalions' trains, as required) and supporting the FSB and the BSA. Specific details on mission assignments will come from the brigade's rear CP. Engineer missions in support of the brigade rear should be close to completion before missions in support of the MBA and rear area are started because of the level of engineer support required.

Survivability support is essential in maintaining combat operations. Engineer survivability support is provided through fortifications and protective obstacles. The brigade S4 is responsible for the protection of the BSA. The brigade engineer working with the BREC plans for the survivability of all units in the brigade rear area. Initial guidance for determining the priority of engineer support for base and base-cluster support operations is laid out in the brigade OPORD. This guidance is based on the brigade engineer's evaluation (in conjunction with the brigade staff and the input received from the brigade rear CP) of the current and expected level of threat activity in the rear area. The priorities are based on the following factors balanced against the threat level:

• Vulnerability of the base cluster.
• Self-defense ability of the base-cluster units.
• Criticality of the unit to the success of the brigade mission.
• Recuperability of the unit and its assets in the base cluster.

Once the priorities are established, the threat level must be understood, and the base-cluster defense must be designed to counter the threat's most probable COA. Obstacle recommendations to support rear-area operations are also based on the three threat levels (see Table 4-2).

Coordinating, tracking, and moving Class IV/Class V (obstacle) supplies forward to the battalions is a principal concern for the brigade engineer and the BREC. Preconfigured packages of Class IV/Class V (obstacle) supplies can greatly simplify planning and execution of logistics operations. Chapter 6 provides details on the CSS process for engineers supporting the light brigade. The brigade engineer's goal is to get divisions or higher assets to throughput the material to the TF sector and coordinate dedicated haul support for moving the supplies once delivered. Transportation assets in the FSB are vital. In restrictive terrain, the lift assets in the aviation brigade provide rapid and flexible haul support.

Other rear-area missions the brigade engineer plans for are as follows:

• Rear ADC.
• HN support.
• Tactical support to the combat force.

Synchronized and integrated engineer support and planning for rear-area operations require dedicated engineer input to the brigade rear CP. Although the MBA consumes the majority of the brigade engineer's planning effort and engineer resources, support to rear operations is essential to ensure the commander's freedom of maneuver and the success of the close operation. Figure 4-18 shows some mission considerations for rear operations.

ENGINEER DUTIES AND CONSIDERATIONS

This chapter covers the basics of an extremely complex operation using the defensive framework as a tool to analyze the process. It is important to remember that the scenario is only a tool to bring out important concepts and procedures for engineer support. To establish the engineer framework and to plan engineer support for the brigade, the brigade engineer uses the engineer estimate, the scheme of engineer operations, subunit instructions, and the brigade engineer annex. Company commanders integrate these tools with their unit orders to prepare and execute the plan.

BRIGADE ENGINEER IN THE DEFENSE

The brigade engineer's main responsibilities in planning and controlling defensive operations are--

• Identifying engineer missions.
• Recommending the allocation of engineer and engineer-mission-related resources.
• Planning, tracking, and synchronizing engineer battlefield functions.
• Understanding threat composition and doctrine.
• Understanding friendly composition and doctrine.
• Determining what engineer resources are needed by using the engineer work estimate.
• Requesting additional resources from the division, if necessary.
• Synchronizing the obstacle plan with the maneuver commander's intent and scheme of maneuver.
• Recommending engineer task organization to the maneuver commander.
• Coordinating fire support to cover brigade obstacles.
• Coordinating with the aviation LO, Air Force liaison, and the fire-support element for FASCAM.
• Monitoring obstacle reports.
• Assisting the S2 in the IPB process.
• Continually updating the maneuver commander on the status of obstacles.
• Providing the brigade S4 with the estimate of Class IV/Class V supplies required for tactical obstacles.
• Providing a terrain analysis of the brigade's sector.

COMPANY COMMANDER IN THE DEFENSE

The company commander is the executor of engineer missions in support of the brigade's defense. He must clearly understand the maneuver commander's intent. Additionally, the commander must do a mission analysis of his sector. The company commander--

• Works closely with the brigade engineer during the planning phase.
• Provides the brigade engineer with the realistic work capabilities of his company.
• Helps foresee problems based on his knowledge of the company.
• Aids the brigade engineer in developing the obstacle plan.
• Conducts a reconnaissance of the assigned sector.
• Issues orders to the company.
• Supervises platoon leaders (TF engineers) on--

- Developing the TF obstacle plan.

- Covering critical points (for example, FASCAM, obstacles covered by observation and fire, and engineer Class V supplies).

- Handling problems brought up by the maneuver battalions.

• Keeps the brigade engineer informed as to the status of survivability effort, obstacle emplacement, and logistics.
• Becomes familiar with friendly and threat weapons systems and must know which ones are most likely to be seen.