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FM 71-3
The Armored and Mechanized Infantry Brigade


As in offensive operations, the brigade commander sets the conditions for success in defensive operations. He uses all organic and supporting systems with precision and at their maximum capability. Ground combat power is then applied to defeat the enemy.

Section I. Fundamentals of Defensive Operations
Section II. Conducting Defensive Operations
Section III. Combined Arms Obstacle Integration
Section IV. Brigade Covering Force Operations
Section V. US Night Defensive Doctrine



The main purpose of a defensive operation is to cause an enemy attack to fail. Brigades normally conduct defensive operations as part of a division- and corps-level defense. They may attack, defend, or delay as part of the security area, MBA, or reserve force. Brigades may also conduct offensive operations across the FLOT while the majority of the division or corps defends, or they may serve as a ground tactical combat force in support of rear operations. Armored brigades possess the type of combat power and mobility ideally suited for mobile defenses. While normally conducting the mobile defense as a part of division or corps operation, in a force projection Army, the brigade commander may find situations where a mobile defense is the best option available at his level.

At times, the brigade may be required to retain key terrain or facilities, or conduct an attack as the striking force of a division or as a reserve force for the corps. The brigade's mission to retain key terrain may be ordered if it assists or creates an opportunity for the higher headquarters to shift to the offensive. Inevitably, the brigade defense focuses on regaining the tactical initiative or creating the opportunity for its higher headquarters to shift to the offensive.


The commander conducts simultaneous operations in depth and organizes the battlefield into three complementary elements of deep, close, and rear operations.


Deep operations are directed against enemy forces and functions beyond the close battle. Generally, the brigade needs additional assets from division to conduct deep operations. These assets may include electronic jamming equipment and attack helicopters. The brigade commander must synchronize these additional assets to simultaneously attack the enemy throughout the depth of the battlefield. Brigades may also maneuver as part of the divisions deep attack.


The MBA comprises the area we typically designate as close operations. Brigades generally array the bulk of their combat power within the MBA. Normally brigades defend within the MBA, act as the higher commander's reserve, or act as part of the division or corps striking force.

The brigade could act as the security force for the higher commander or it could provide its own security force, although this is not desirable. In either case, the brigade conducts passive and active reconnaissance and security measures throughout the depth of AOs.

The brigade commander retains a reserve force based on the threat force assessment. The task and purpose for the brigade reserve unit are identified during the wargaming process. The reserve is committed at the decisive point to ensure the defeat of the enemy force.


The brigade's rear operations include self-protection of its units and protection and maintenance of its LOCs. The brigade normally designates a tactical force to react to rear threats. Rapid response ability to a rear area threat, particularly Levels II and III threats, is integral to the commander's ability to sustain a viable defense. The brigade may also be tasked to provide tactical forces to support the higher commander's AO.



A brigade generally does not conduct a mobile defense, but conducts area defensive or offensive operations as part of the divisions defense (see Table 5-1). A mobile defense orients on the destruction of the attacking force by permitting the enemy to maneuver to a position of disadvantage that exposes him to the striking force. A brigade may conduct a movement to contact or deliberate attack as part of a division or corps striking force.

Table 5-1. Characteristics of forms of defense.



Orients on the enemy (destruction or defeat) Deny enemy access to designated terrain for a specific time
Mobility greater than or equal to the enemy Mutual supporting positions and in depth
Defend with minimum force Defend with maximum force
Fire and maneuver Interlocking fires
Striking force Smaller mobile reserve for local counterattacks
Striking force used at the decisive point


A brigade conducts an area defense as part a division or corps defense. Area defense orients on retention of terrain or facilities for a specified time. When planning the area defense, the brigade commander decides the decisive point, when to concentrate his main effort, and where to economize forces based on his own estimate of the situation and the higher commander's concept. He then assigns missions; allocates forces, fires, and other support; and sets priorities for resources to fight a combined arms battle.

The brigade commander elects to defend forward or in depth based on METT-T and higher commanders intent. A defense in the forward part of the sector requires early commitment of the main defensive effort. This may be achieved either by an initial forward deployment of forces or by planning counterattacks well forward in the MBA or even forward of the MBA. A defense in depth may be selected when missions are less restrictive, defensive sectors are deep, and key terrain lies deep in the sector. A defense in depth relies on elements in the security force area and forward elements in the MBA to identify, define, and control the depth of the enemy attack. The flanks of the enemy main effort are counterattacked to isolate and destroy enemy forces in the MBA.


The brigade commander integrates and synchronizes all assets to maximize combat power. To effectively focus combat power, the brigade commander designates the brigade main effort; this links each subordinate commander's actions to those around him, providing cohesion and synchronization. As the brigade commander develops his battle plan for the employment of maneuver forces, he must visualize how he will synchronize his FA, air defense, EW, NBC, engineer, CAS and any joint or multinational supporting assets at the decisive time and place on the battlefield.


The brigade S2 focuses on IPB in planning for the defense and analyzing the close operation to predict and confirm enemy intentions. Before the battle, the brigade commander requires specific information about:

  • The composition, equipment, strengths, and weaknesses of the advancing enemy force.
  • The location, direction, and speed of enemy reconnaissance elements.
  • The location and activities of enemy follow-on forces.
  • Enemy initial and follow-on regimental or brigade command, control, and communication facilities.

The brigade staff prepares a detailed R&S plan to focus reconnaissance assets at enemy decision points, thus confirming the enemys adopted course of action.

Maneuver (Aviation)

The inherent speed, agility, flexibility, and lethality of aviation elements make them an offensive asset that the brigade can employ to assist in seizing and retaining the initiative. Army aviation can also be used to attack and destroy the enemy when and where he is most vulnerable. Aviation units OPCON to the brigade can conduct attack operations, air assaults, reconnaissance, and security missions with ground operations. Attack helicopter battalions/aviation task forces should be augmented with ground forces when assigned guard and/or covering force missions.

Logistics support of aviation units remains the responsibility of the aviation brigade; however, forward support aviation logisticians are coordinated with the FSB operations section in the BSA.

For a detailed discussion on ground maneuver, see Section II of this chapter.

Fire Support

The brigade commander weights the main effort by establishing FS priorities. FS is synchronized with maneuver forces to disrupt and weaken the enemy's attack to provide opportunities for friendly counterattack. The FSCOORD uses the IPB process, intelligence gathering resources, and the TVA process to focus all supporting fires.

Control of FS assets is centralized for defensive operations. Ammunition is pre-positioned and firing positions are surveyed in advance. The FSCOORD focuses his planning effort on the following tasks:

  • Engaging the enemy early to disrupt the cohesion of its attack and reduce its intelligence gathering capability. As the enemy enters the security area and MBA, FS will continue to reduce enemy intelligence gathering ability to mass combat power.
  • Supporting rear operations.
  • Providing deep fires to delay and disrupt reinforcing units.
  • Screening friendly movements.
  • Providing counterfire to limit the enemy's ability to shift combat power rapidly.
  • Integrating fires with the brigade obstacle plan.

The brigade synchronizes the MBA to mass the effects of all FS assets.

Air Defense

The brigade uses a combination of passive and active air defense measures. Priorities shift toward protection of the covering force, FS elements, BSA, and command and control facilities. Maneuver units are integrated into the counterair plan by engaging appropriate targets within the capabilities of the weapon systems. Collection and early dissemination of air threat information are required to make this system work. ADA units require engineer support to dig firing positions for Bradley Stinger fighting vehicle (BSFV) systems.

In defensive operations, air defense assets are positioned to achieve mass. Normally, the priority of protection will begin with the command and control facilities. That is because these are generally fixed sites with high electronic signatures, which makes them susceptible to identification and targeting by threat aircraft. Therefore, the brigade air defense representative will examine the air avenues of approach toward the command and control facilities and position both guns and missiles in a manner that disallows the threat aircraft to reach the target.

Mobility and Survivability

The priority of engineer effort in the security area is normally given to mobility of the passing units of the covering force, then to countermobility to delay the advance of threat units. Priority for engineer support in the MBA is determined by the brigade commander based on METT-T. A trade-off between countermobility and survivability exists because of limited resources. Obstacles are emplaced in depth to support the maneuver commander's scheme and are integrated into the FS plan to maximize the effect of friendly fires. Counterattacks may require improvement of mobility corridors to ensure success. Priority of engineer effort in the rear is given to mobility, then to survivability for command, control, and communications, reserve, and CSS assets.

Defensive operations require intensive management of engineer resources allocated to support the brigade plan. The resources usually consist of a combination of divisional and corps engineer units. The assistant brigade engineer and the brigade S4 coordinate early to forecast and request the large quantities of required Classes IV and V materials and munitions.

Nuclear, Biological, and Chemical Defense

Throughout the planning process, the brigade commander plans for possible enemy use of NBC weapons and for employment of NBC defense units.

The commander also determines decontamination priorities. All plans and operations of forces and installations are analyzed by the S3 and chemical section to determine their vulnerability to these weapons. The commander specifies the degree of risk he is willing to accept. The brigade chemical section can suggest changes to the concept of the operation if the concept involves unacceptable risks from enemy weapons.

Chemical Reconnaissance

Brigade NBC reconnaissance operations in the defense normally focus on identifying clean areas, BPs, movement routes, decontamination sites, and contaminated areas that directly affect operations. The information gathered from the reconnaissance effort is immediately passed to higher, lower, and adjacent units and periodically updated.

Combat Service Support

The S4 and the FSB commander must understand the brigade commander's intent so that service support priorities can be established and logistical operations planned to ensure the supportability of the operation. Real estate management of the BSA and plans to conduct operations against Levels I and II rear area threat must be incorporated into the plan. The following considerations and operational techniques improve the CSS provided to a defending unit:

  • Limited amounts of ATP-stocked ammunition (25 percent of basic load) are pre-positioned in the MBA on centrally located positions.
  • Push-packages of certain critical items (ammunition, POL, selected repair parts, barrier materials, medical supplies, and NBC supplies) are dispatched from rear areas (division support areas to brigade support areas to unit trains) on a scheduled basis so that interruptions in communications do not disrupt the flow of supplies.
  • Class IV and Class V point for countermobility push-packages are established.
  • Resupply during periods of limited visibility reduces chances of threat interference. Resupply vehicles infiltrate forward to reduce chances of detection.
  • CSS units are echeloned in depth throughout the defensive area. When a forward CSS unit is required to displace to the rear, another unit picks up the workload until the displacing unit is again operational.
  • Maintenance contact teams are employed and dispatched as far forward as possible to cut down on the requirement to evacuate equipment. The thrust of the maintenance effort is to fix as far forward as possible.
  • Different types of maintenance contact teams (vehicle, armament, missile) are consolidated to use the available vehicles.

Command and Control

After completing the estimate of the situation, the brigade commander announces his decision and concept of the operation to key members of the staff. The concept is in enough detail for his staff to understand how he intends to conduct the battle. Staff preparation of plans and orders is based on the commander's concept. Subordinates are given maximum possible time to prepare since the effectiveness of the defense depends on time-consuming tasks, such as reconnaissance, fire planning, preparation of positions, installation of obstacles, positioning of supplies, and improvement of routes. WOs and subsequent oral instructions are used to get the word out. Commanders do not wait for the complete plan to begin preparations.




Brigade commanders need information to fight the close-in battle of the brigade against the OPFOR. They also need accurate intelligence about OPFOR elements that can close on their area of operation before the current engagement can be decisively concluded.

The brigade commander needs specific information about the:

  • Composition, equipment, strengths, and weaknesses of advancing forces.
  • Location, direction, and speed of OPFOR battalions and their subordinate companies.
  • Location and activities of OPFOR follow-on echelons capable of reinforcing the first echelon.
  • Location of OPFOR indirect-fire weapon systems and units.
  • Location of gaps, assailable flanks, and other tactical weaknesses in the threat's order of battle and OPSEC posture.
  • Locations of antiaircraft and missile artillery units.
  • Location of surface-to-air missile units.
  • Location of radioelectronic combat units.
  • Effects of weather and terrain on current and projected operations.
  • Most likely withdrawal routes for threat forces.
  • Anticipated timetable or event schedule associated with the threat's most likely COA.

Specific information about OPFOR command, control, and communications facilities is of paramount concern to the brigade commander. He seeks to know the specific locations of threat

  • Division forward and main CPs.
  • Regimental and battalion CPs.
  • Fire direction control (FDC) centers.
  • CPs and OPs.
  • Radio and radar reconnaissance sites.
  • Radioelectronic combat sites.
  • Target acquisition sites.

The suppression, neutralization, and/or destruction of threat command, control, and communication systems and facilities are critical to the success of the close-in battle. Brigade S2s, in concert with supporting division and corps IEW, maneuver, and FS units, use all available means to identify, locate, disrupt, and destroy these targets. Their objective is to neutralize the threat commander's capability to command and control troops. Normally, the brigade S2 receives his information from the following sources:

  • Maneuver unit observation spot reports (SPOTREP)/patrols.
  • FA units. Weapons locating radar, cannon, rocket, mortar.
  • Air defense units. Forward area air defense command and control communications and intelligence (FAADC3I).
  • MI assets.
    • GSRs
    • Remote sensors.
    • Counterintelligence support.
    • Prisoner of war interrogation (IPW) teams.
    • Aerial surveillance side looking airborne radar (SLAR).
    • Ground EW assets collection and jamming.
    • UAVs.
  • Aviation.
    • Reconnaissance flights.
    • In-flight reports.
    • Divisional special purpose countermeasure system
    • Quick fix 11B.
  • All source analysis system (ASAS).

The brigade commander determines where to position his forces based on the enemys maneuver options. He desires to build depth based on terrain and how it affects the enemys maneuver options. If the terrain is restrictive and does not allow depth behind him, he compensates by early commitment of main defensive forces. If necessary, counterattacks may expand the forward area if the opportunity exists. Further depth is created by security forces and deception operations that lead the enemy to believe that the main defensive battle area is further back. When the terrain or mission is less restrictive, the brigade commander builds depth with security and covering forces by selecting key terrain deeper in the area of operations and conducting deception operations that lead the enemy to believe that the defense is forward.

Brigade commanders organize the battlefield for defense by assigning either sectors or BPs to subordinate battalions or task forces.

Sectors give the battalion task forces freedom to maneuver and decentralize fire planning. They allow the task force commander to distribute his teams to suit the terrain and plan a battle that integrates direct and indirect fires. The brigade commander conducts a backbrief with the battalion commanders to approve and deconflict their plans. A defense in sector requires continuous contact with flank units for security.

BPs are used when the brigade commander wishes to control maneuvering and positioning of his task forces. They are also used when it is necessary to concentrate task forces rapidly. When the brigade commander establishes BPs, he controls maneuver outside those BPs. He prescribes primary directions of fire by the orientation of the position, and is responsible for fire and maneuver planning between positions of different battalions. If he assigns a BP and a sector, he is giving the task force commander specific guidance on initial positioning of forces.

A strongpoint is a heavily fortified BP tied to the natural and reinforcing obstacle to create an anchor for the defense. A strongpoint is located on a terrain feature critical to the defense or used to block a bottleneck formed by terrain obstacles. Strongpoints in small urban areas, astride routes, or along assembly areas may halt a superior threat force for a considerable time. To be most effective, the strongpoint should be a surprise to the threat. It causes congestion and limits the threat force's maneuver. It is best used to set up a counterattack. Strongpoints must be well camouflaged and protected.

Control measures, such as PLs, boundaries, contact points and passage points (PP), checkpoints, direction of attack arrows, and objectives combined with fire control measures to provide a means of controlling the battle.

The commander's tactical scheme must include plans for deep, close, and rear operations. The objective of the defense is to halt the enemy, seize the initiative, and go to the offensive. The commander's tactical scheme must include plans to counterattack against the threat rear or flank whenever possible. The brigade reserve is the key to the execution of offensive operations.

The Reserve

The brigade commanders most critical decision during the defense is the commitment of the reserve. Commitment of the reserve is the most effective way the brigade commander can influence the battle. Once committed, the reserve becomes the brigade main effort. Early in his planning, the brigade commander makes fundamental decisions concerning the size, composition, and mission of the reserve. A major purpose of the reserve is to regain initiative through offensive action. The reserve does this by conducting counterattacks, spoiling attacks, and raids against the enemy, preferably to its flanks and rear. Other purposes of the reserve are to:

  • Block penetrations.
  • Contain enemy forces that have penetrated.
  • React to rear area and flank threats.
  • Relieve depleted units and provide for continuous operations.

If the brigade commander does not have sufficient reserves of his own, he may require his subordinate task force commanders to obtain his permission before the employment of their reserves. He may also specify the location of their reserves. METT-T will dictate the size and composition of the reserve. The reserve must remain concealed until committed. This protects it from enemy attack and enhances the shock effect when it is committed.

The brigade commander immediately reconstitutes a new reserve as soon as the original reserve is committed. This restores his ability to influence the battle with maneuver forces. Even a small reserve can be decisive in tipping the balance of victory.

The brigade commander uses DPs developed during the construction of the DST to trigger execution of contingency plans for his reserve (see Figure 5-1). The reserve makes maximum use of the defensive preparation time to rehearse each contingency plan, in priority.

Rehearsals are conducted, both day and night, to the lowest level possible. Target areas of interest (TAI) are developed to support the reserve when it is committed.

In planning contingencies for offensive actions of the reserve, the brigade commander considers the enemy situation and estimates the TDIS factors related to follow-on enemy echelons based on the IPB process. Then he determines which of his units will attack, where they will attack and be positioned after the attack, and what interdiction or deep attack is necessary to isolate the enemy. The commander must also consider the TDIS factors required to focus his combat power at the decisive point to defeat the desired enemy force.

Although he plans for the counterattack, the brigade commander must realize that it is unlikely the action will correspond exactly to expectations. As the situation develops, the commander answers these basic questions:

  • Will an attack facilitate the higher commanders intent?
  • Is an attack feasible or should the reserve be employed to contain enemy success?
  • When and where should the attack be executed?
  • In the event of multiple penetrations, which should be attacked and which should be blocked or contained?
  • Is the window of opportunity large enough to complete the counter-attack before the closure of the next enemy echelon?

The Reserve and the Spoiling Attack

At times, reserves are used in a spoiling attack role to throw the enemy preparations for the attack off stride. Basic considerations for the spoiling attack follow:

  • The spoiling attack delays, disrupts, and destroys the enemys capability to launch its attack or commit a following echelon.
  • The objective of the attack is to destroy enemy personnel and equipment, not to secure terrain and other physical objectives.
  • Spoiling attacks are not conducted if the loss or destruction of the force jeopardizes the ability of the command to accomplish its defensive mission.
  • Mobility of the force available for the spoiling attack should be equal to or exceed that of the enemy force.
  • FS assets attack available enemy reinforcements to ensure the success of the spoiling attack.

Commanders coordinate plans for counterattacks and spoiling attacks using the attack techniques discussed in Chapter 4, Offensive Operations. The spoiling attack has many of the characteristics of hasty attack and raid operations.

Reinforcing with the Reserve

In some situations, the brigade commander determines that he cannot counterattack with a reasonable chance of success. He positions the reserve to contain or delay the enemy to gain time for the employment of the reserve of the higher echelon.

The transition from a defensive posture to the offensive is not exclusively the responsibility of the reserve. A variety of tactical situations may offer the opportunity for, or even require, defending units to launch hasty or immediate attacks. Such situations include:

  • Breakout from encirclement.
  • Relief of encircled forces.
  • Raids and spoiling attacks.
  • Collapse of enemy resistance or unanticipated enemy withdrawal.

As they plan their battle, the brigade commander and staff consider how reinforcing battalions and companies will be integrated into the defensive scheme. This planning includes placement of BPs, the routes, and the command and control arrangements. Supporting engineer and MP assets must maintain route trafficability to enable timely movement of the reserve throughout the brigade sector. For the MP, this includes ensuring designated routes remain clear of dislocated civilians. Positioning and movement of reinforcements are enhanced by designating the routes and providing traffic control personnel and guides at contact points to lead reinforcements and brief them on the situation.

One way the brigade commander weights the main effort is by establishing FS priorities. Close and deep fires are synchronized with maneuver forces to disrupt and weaken the enemys offensive action and to provide windows of opportunity for friendly offensive action. The FSCOORD uses the IPB process, full integration of intelligence gathering resources, and the TVA process to focus FS on the systems vital to the enemys success.

Synchronization of direct and indirect fires with obstacles multiplies effects on the enemy. An obstacle is an excellent location for preplanned artillery/mortar fires and for eliminating small breaching teams. The indirect fire effects will contribute to the enemys difficulties in attacking through the obstacle, making it more effective and providing direct-fire systems a higher probability of kill. Only critical obstacles should be targeted. The FA battalion cannot cover all obstacles. To be effective, the FA should be massed only on those obstacles that are key to the success of the battle, and can best maximize all brigade weapon systems.


The object of a successful defense is to know what the enemy will do before he does it. During the rehearsal, subordinate commanders explain their R&S plan; who they call upon sighting the enemy; and the specific PIR for which they should be looking. The commander decides the COA appropriate for the situation. The maneuver commanders must demonstrate their flexibility in adapting to a rapidly changing situation.

The commander rehearses the synchronization of his combat multipliers with the maneuver. The intent of the brigade commander is to practice the controlling of these assets as a single activity.

The brigade engineer and staff monitor the preparation, revise the timeline, and keep the brigade commander informed. Task force plans and overlays are checked to ensure EAs are properly developed and the commander's intent achieved. Execution matrices should reflect a clear synchronization between the obstacle intent and fires.

There is no substitute for a thorough ground reconnaissance to confirm the plan. Obstacle siting procedures confirm the linkage between fire control and obstacle intent.


The brigade commander, with key staff, normally fights the battle from the TAC CP; however, his personal presence may be required at critical points, such as battle handover from security forces or commitment of the reserve.

Because command and control facilities are more static than in the offense, emphasis must be placed on locating them in hardened areas or protective terrain and reducing electronic signature. The main CP should be located as far to the rear as possible while maintaining reliable communications with the TAC CP, deep assets, and subordinate battalions. The main CP focuses on monitoring the progress of the battle, forwarding information (higher and lower) and support requests (higher), and coordinating supporting units.

The rear CP anticipates future support requirements; it coordinates with the FSB commander to ensure continuous logistics support to enable friendly units to regain the offensive. It also focuses on continuity of support for current operations and control of brigade CSS units moving forward from the BSA. The rear CP must continuously monitor the battle and be prepared to immediately assume the role of the main CP, if necessary.


A brigade commander conducts a mobile defense if directed by his higher headquarters or it is determined as a result of his estimate of the situation and approved by his higher commander. A mobile defense is generally conducted when the enemy possesses inferior mobility, or when defending vast featureless terrain against a sizable enemy force. Likely situations when a brigade would conduct a mobile defense are when it is the assault echelon for a division or when conducting an economy-of-force role on a flank of a division or corps defense. In both situations the enemy force will most likely outnumber the friendly force as assessed over a given time period.

The brigade commander normally employs a covering force, fixing force or forward defensive force, striking force, and reserve force (if forces are available).

The covering force has the task of covering for the main body, identifying the enemy main effort, and assisting in shaping the battlefield for commitment of the striking forces. The covering force should be a self-contained force. The commander for the covering force is augmented with available FS assets as needed to assist the brigade commander in shaping the battlefield and destroying selected deep targets. Units in the covering force must clearly understand the brigade commander's intent and what actions or events that appear to the enemy as successful. It is important for all units in the covering force to allow the enemy to move in a specific direction without a great deal of influence if the enemy is moving towards the striking forces' EAs.

The forward defense force has the task to delay and fix the enemy force for a specific time to allow the striking force time and space to maneuver. The forward defense force may consist of any appropriate force necessary to conduct delaying and fixing tasks as determined from the commander's estimate of the situation. Continuous coordination with the covering force must be maintained to ensure no enemy reconnaissance or maneuver forces bypass them and interrupt the maneuver of the striking force.

The striking force is comprised of the maximum combat power available to the commander at the time of attack. The striking force must have equal or greater combat power and mobility than the enemy. Combat power should factor in such things as surprise and include all available forces, ground and air maneuver, and FS assets (joint and combined). The striking force is a committed force and is the main effort of the brigade upon its commitment. While destruction of the enemy is normally the primary objective, other objectives may include breaking up the enemy's momentum, disrupting his timetable, or causing him to shift his forces, all of which buy time for friendly forces.

A reserve force, if available, may be employed to assist in shaping the battlefield or to destroy enemy forces that bypass the forward defense force. Attack helicopters are ideally suited to conduct a counterattack to stop an enemy penetration.

The brigade commander specifies the defensive pattern in his mission statement and ensures all tasks assigned to subordinate units support his scheme of maneuver.

Engineer assets must resource the forward defense force and the striking force. Priority of effort to the forward defense force is survivability and countermobility. Priority of effort to the striking force is mobility and then countermobility. The brigade commander designs a plan that uses obstacles to turn and fix the enemy but ensures attack routes for the strike force are clear. Aerial delivered mines should be planned to help shape the battlefield. A maneuver force element within a striking force organization may have to conduct a hasty breach and attack through a short duration minefield after the minefield has been disarmed. The brigade plans and rehearses all breaching operations to ensure no time is wasted, which may impact on commitment of the striking force.

The brigade commander retains control of the striking force and the reserve force, if designated. The brigade is the echelon conducting a mobile defense, and all other subordinate units not in the striking force conduct an area defense, strongpoint, or delay in sector for a specific time. The brigade commander provides the striking force commander with the decisive point, objective, and EAs where the enemy force is to be destroyed. The brigade commander clearly understands and articulates to the striking force maneuver commander the size and composition of penetrating enemy forces to be destroyed within the EAs. The striking force commander is provided updated information on the enemy as it moves toward designated EAs.

A mobile defense assumes risk because the defending brigade retains the majority of its combat power in the striking force or is positioned to support the striking force. The risks are twofold. First, the forward defense force is not adequate in strength to accomplish the mission alone. The success of the mobile defense depends on successful commitment and accomplishment of the assigned purpose of the striking force. Second, the enemy may not maneuver or be forced into an area where the brigade commander intended and commitment of the striking force is not accomplished.

Detailed rehearsals at brigade and battalion levels are essential to ensure all forces understand their assigned tasks and purposes, and they can execute them without detailed guidance from the commander. Communications is key to success and assets must be planned and positioned to support each transition phase without disruption.

The supplies required when conducting a mobile defense vary based on the task assigned to units within the overall scheme of maneuver. The covering force requires Class III and V (maneuver and engineer) increases to support its operations. Medical evacuation (MEDEVAC) and recovery evacuation assets may need augmentation and must be carefully planned and rehearsed to support the covering force. The defending force requires significant quantities of Class V and Class IV. The striking force requires greater amounts of Class III during the attack and Class V, maintenance, and medical support after the attack. The commander designates his priority of CSS by phase and develops a flexible plan to shift priority as the situation changes.


Obstacle control is a tool that commanders use to assign responsibility and to provide control for obstacle emplacement (see FM 90-7 for more information). To achieve obstacle control, commanders use obstacle control measures and obstacle effects graphics that allow a commander to graphically define the area in which subordinates can plan tactical obstacles.


Obstacle Zones (Division) and Belts (Brigade)

The division commander uses obstacle zones and the brigade commander uses obstacle belts to limit the area where subordinates are authorized to employ tactical obstacles so that there will be no conflict with the higher commander's plans for maneuver. Commanders draw obstacle zones and belts to give subordinate commanders maximum flexibility to use obstacles but still ensure that effect of the obstacle supports the overall plan. Obstacle control measures imply authorization to employ all types of obstacles not listed as restricted within the confines of the obstacle control measure.

Obstacle Belts

Brigade obstacle planning concentrates on the development of obstacle belts to further focus the location and effect of tactical obstacles within the brigade sector. Obstacle belts are the primary means the brigade commander uses to further control brigade tactical obstacle employment within his AO. The brigade commander designates obstacle belts within his assigned obstacle zone(s) that further define areas where battalions are authorized to employ tactical obstacles. Belts enable the brigade commander to directly link tactical obstacle effects to the brigade FS plan and the direct fire responsibilities for assigned task forces.

Obstacle belts are simply a refinement or subset of the obstacle zone in which they are planned. The area defined by the belt must not violate the boundaries of the parent zone. Obstacle restrictions imposed by the parent zone apply to all belts within the zone. The brigade commander may add restrictions to a particular belt, but they are in addition to any imposed by the division obstacle zone.

The brigade commander assigns each obstacle belt a specific obstacle effect. This gives purpose and direction to task force obstacle planning. Both the FS plan and direct fire responsibilities are brigade driven. The brigade commander must also assign specific obstacle effects to each belt to ensure obstacles within the belt complement the brigade fire plan. The commanders intent conveys the overall effect that must be achieved by fire and obstacles against a specific target within the defined belt of his task force commanders.

The brigade commander uses obstacle belts to attack the maneuver of enemy brigades/regiments. Belts are planned and allocated against brigade avenues of approach based on battalion mobility corridors. This is consistent with the brigade planning, which allocates companies against battalion mobility corridors and task organizes battalions to defeat enemy brigades.

Obstacle Groups

Task force obstacle planning focuses exclusively on establishing an inseparable union between obstacle effects and the fire plan by planning obstacle groups. An obstacle group is a collection of individual obstacles designed and arrayed to produce a singular, specific effect on an enemy battalion-size formation. Detailed task measures and fixed company responsibilities allow the task force commander to fix both group effect and location to support his fire plan.

Obstacle Restrictions

Commanders use obstacle restrictions to limit certain types of obstacles inside an obstacle control measure. These restrictions ensure that subordinate commanders do not employ obstacles with characteristics that impair future operations. It also allows the commander to focus the use of limited assets and resources for the main effort by restricting their use elsewhere. Obstacle restrictions preclude employment of the designated type of obstacle within the obstacle control measure. Battalion commanders have the right to be more restrictive than the brigade commander; however, the battalion commander cannot lower the brigade commander's restrictions.


Tactical obstacles are used to directly attack the enemy's ability to maneuver, mass, and reinforce. All tactical obstacles 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 directed, reserve, and situational obstacles.


All tactical obstacles produce one of four primary obstacle effects: to block, to turn, to fix, or to disrupt (see Figure 5-2). Obstacle effects manipulate the enemy in a way that supports the commander's intent and scheme of maneuver. Obstacle effect drives integration, focuses subordinates' fires, focuses obstacle effort, and multiplies the effects of firepower. Remember that obstacle effects occur because of fires and obstacles, not just obstacles alone. The brigade commander and staff must understand the exact effects that tactical obstacles produce. Precise use of the obstacle effects are necessary to translate concepts to fire and obstacle planning.

Obstacle effect is always expressed using the standard tactical obstacle effects. The desired obstacle effect must be clear to subordinates since it provides a common expectation of the effect fires and obstacles have on enemy maneuver. The brigade commander uses standard obstacle effects graphics to convey obstacle intent to his staff and subordinates. Tactical obstacle effects are unique for each type.


Blocking obstacles are used to integrate fire planning and obstacles to stop an attacker along a specific avenue of approach. Fire plans covering blocking obstacles are primarily oriented on stopping enemy maneuver. This effect focuses on retaining terrain and protecting the integrity of the obstacle rather than completely destroying the attacking force. The success of the blocking obstacle is measured by the impact on the enemy advance rather than enemy losses. The blocking obstacle is the most resource intensive type of tactical obstacle; commanders should use it only at critical points in the battle.


Turning obstacles are used to divert an enemy into an EA and expose his flanks. Commanders use turning obstacles within EAs to divert an enemy formation off one avenue of approach to another avenue in support of the scheme of fire. Fire control must be planned to maintain pressure on the enemy throughout the turn and exploit his exposed flank. Fire control to complement the turning obstacle must initially promote overwhelming volumes of lethal fires at the start of the turn and then maintain fires on the enemy.


Fixing obstacles are used to focus fire planning and obstacle effort to slow an attacker within a specified area, normally an EA. Obstacles and fires are planned in depth and build with intensity to complete the enemy's destruction within the specified area. The fixing obstacle allows fires to defeat the enemy in detail or gain the necessary time for forces to reposition while inflicting maximum casualties. To complement the obstacle, the direct and indirect fire plan must:

  • Cause the enemy to deploy into attack formation.
  • Allow the enemy to advance within the EA.
  • Make the enemy fight in multiple directions once in the EA.
  • Depth, increasing intensity, and interlocking fires are all vital characteristics of fire plans covering the fixing obstacle.

Figure 5-2. Obstacles function versus lethality.

  • 60-100% LETHALITY
  • 30-60% LETHALITY
  • 10-30% LETHALITY

Figure 5-2. Obstacles function versus lethality.


Disrupting obstacles are used to break up an enemy's formation, interrupt his timetable, cause the premature commitment of breach assets, and piecemeal his attack. This obstacle effect may be used to separate combat echelons or separate combat forces from their logistical support. In close operations, obstacles are normally used just forward of EAs or in support of forward positions within a defensive sector. Control measures covering the disrupting effect combine obstacles and indirect fires against a portion of the enemy to break up the formation while direct fires mass against the force allowed to bypass the obstacles.


Reserve obstacles are those for which the commander restricts execution authority (road crater and bridge). These are "on order" obstacles. The commander usually specifics the unit responsible for obstacle emplacement, guarding, and execution. The brigade commander must clearly identify the conditions under which the obstacle is to be executed.

Obstacle location is a vital component of obstacle intent since it ties the obstacle effects and target to the scheme of maneuver. Wherever possible, commanders give obstacle locations relative to maneuver or fire control measures to integrate the effects of obstacles.


Situational obstacles are obstacles that units plan, and possibly prepare, before beginning an operation; however, they do not execute the obstacles unless specific criteria are met. Therefore, units may or may not execute situational obstacles, depending on the situation that develops during the battle. They are "be prepared" obstacles and provide the commander flexibility for emplacing tactical obstacles based on battlefield development. For further information see FM 90-7.

The primary tool used for countermobility by the force are mines and wire. The mines that are employed by divisional combat engineers are conventional and scatterable mines. For detailed information see FM 20-32. The FASCAM systems are:

  • Area denial artillery munition (ADAM) (M731) is an artillery-delivered, AP mine activated by deployed tripwires. A single M483, 155-mm howitzer shell dispenses 36 ADAM mines.
  • Remote antiarmor mine (RAAM) (M741) is an artillery-delivered antiarmor magnetically activated by passing vehicles. A single M483, 155-howitzer round dispenses 9 RAAMs.
  • Gator (CBU-89/B) is a tactical-fixed-wing-delivered, AP and AT mine system activated by both tripwire and magnetic influence. A single CBU-89/B load will cover an area of 200 by 650 meters.
  • Volcano (M87) is a modular mine delivery system for rapid dispensing of AP and AT mines from a five-ton dump truck, the UH-60 helicopter, and the M548A1 tracked cargo carrier. A single Volcano load of 960 mines can produce a minefield 1,110 meters by 120 meters wide.
  • The modular pack mine system (MOPMS) is a man-portable, 162-pound, suitcase-shaped mine dispenser that can be emplaced anytime before dispensing mines. When dispensed, 21 (17 AT and 4 AP) mines are propelled in a 35 meter semicircle to the front of the container.

Obstacle Integration

Obstacle integration creates an inseparable link between fires and obstacles. Neither fires nor obstacles employed by themselves can match the effectiveness achieved by both when they are integrated. Fire control and obstacle planning combine to achieve the commander's intent. Commanders must establish their obstacle intent concurrent with organizing and developing the fire plan. Each component of obstacle intent directly impacts on the fire plan. Fire control measures are required to maximize obstacle effect. Obstacle planning does not drive fire planning. Both obstacles and fire control measures must be planned, adjusted, and executed to meet the commander's intent.

Each tactical obstacle effect produces a unique result on enemy maneuver and demands unique fire control. The relationship between obstacle effects and fire control must be understood by all echelons.



A brigade may be given a defensive covering force mission when the division has sufficient resources and the intent of the commander is to influence and shape the battlefield forward of the MBA. Covering force operations may run the spectrum from a division cavalry squadron conducting a screen, to a reinforced squadron conducting a guard, to a brigade-controlled element operating independently as a covering force.

A brigade given a covering force mission may consist of the division cavalry squadron, three to five armored or mechanized battalions, and an attack helicopter battalion (see Figure 5-3). This organization is responsible for inflicting casualties forward, but not to the point of discouraging the enemy from attacking according to its plan. It is important that the covering force shape the battle so that the forces in the MBA can complete the final destruction of the enemy.

The IPB for the covering force operation is extremely important, as the division commander wants to identify the enemy's main effort and location of follow-on forces for the brigades in the MBA. The actual IPB planning is accomplished as it would for defensive operations; however, the S2 has to concern himself with more avenues of approach and a larger number of enemy forces. The S2 plans his IPB with the assistance of the division cavalry squadron and attack helicopter battalion S2s, who may have their own specific intelligence needs. They are used to work in operations with a divisional scope. They may provide valuable input in terms of the special considerations inherent to covering force operations of which the brigade S2 (as an MBA player) may not be aware.

The brigade FS plan is essential to the commander and his projection of firepower to the enemy in depth. In particular, he wants the FS plan to separate enemy echelons so that they can be defeated one at a time. Further, along the axis of the enemy's secondary effort, FASCAM and interdicting fires are planned to complete the enemy's loss of momentum. The actual planning and coordination of the fire plan occurs as for any brigade defensive operation with one exception: the artillery will not only accompany the covering force but also fire exclusively in its support. Therefore, the FS plan is prepared with more certainty in terms of the amount, timeliness, and sustainment of fires.

The obstacle plan is developed concurrently with the FS and maneuver plans. Given the frontage in which the brigade must operate, the ability of the engineers to construct barriers is limited to carefully selected targets designed to enhance the effect of both direct and indirect fires. Larger obstacles designed to turn and shape the enemy's maneuver simply may not be possible unless the brigade receives large amounts of engineer support.

The brigade S4 and the FSB commander must be prepared to support the covering force forward of the MBA. However, due to the fluidity of the operation and the knowledge that the covering force conducts a rearward passage of lines at the completion of the mission, CSS assets remain mobile so as not to impede the movement of the covering force. To accomplish this, the BSA consists of only those essential activities determined by the FSB commander within the guidance of the brigade commander. This lighter and more mobile FSB should be oriented on evacuation of casualties and damaged equipment, resupply of Classes III and V, and to a limited extent, vehicle and weapon maintenance. Coordination is made with the support systems of MBA brigades to augment the evacuation of casualties and vehicles through AXPs and UMCPs, which are positioned where the depth units can assist in the evacuation.

Much of the command and control of the covering force battle is decentralized due to the distances covered and the decisions each battalion task force or squadron commander (SCO) is required to make during the operation. The brigade commander wants to position himself and the TAC CP in the sector adjacent to the enemy's main effort, as this is the most critical area of the battlefield. The S3 observes the enemy's secondary effort and ensures that he maintains communication with the brigade commander. Due to the lack of an additional headquarters element to accompany the S3, he collocates with the battalion task force or squadron main CP. In this manner, he ensures communications with the brigade main CP and the TAC CP without degrading his mobility.


The commander ensures that his intent is understood and that his subordinates can execute as a team without further guidance. He ensures that he controls the operation and maintains flank coordination through every phase. He rehearses the synchronization of the counterattacks and engagements in main kill zones. He checks the TDIS analysis against the DST to ensure that his forces can arrive at the decisive point of the battle at the correct time. In particular, he exercises the execution of brigade priority targets and reserve demolitions to ensure that they contribute to the effectiveness of the plan as desired. Finally, the commander reviews the coordination necessary to effect the rearward passage of lines at the completion of the operation.

The covering force reserve, whether ground or air, rehearses how it plans to maneuver to each sector. This determines if there are any conflicts between the obstacle plan and the counterattack plan. Similarly, the air routes used by the attack helicopters should be checked against the FS and air defense plans. Airspace coordination measures should be coordinated through the division A2C2 element in the division TOC.

The brigade S4 and FSB commander conduct a CSS rehearsal coincidentally with the maneuver rehearsal. The ability of the support elements to sustain the force during combat is essential to the success of the operation. In particular, the support players verify that the MSRs and lateral supply routes remain unencumbered by the obstacle plan and that support elements reach each maneuver element. Prestocks and LRPs should be checked against BP locations. Linkage with CSS elements from the MBA should be checked to ensure coordination is complete. If possible, representatives from the MBA attend the rehearsal.


As the enemy's reconnaissance elements reach the CFA, they are engaged and destroyed by the battalion task forces and cavalry squadron. Whether their mission is to defend or delay, it is essential to blind the enemy divisional commanders by stripping away their ability to collect information. The commander closely monitors the front line trace of the covering force to ensure that his subordinate commands maintain flank coordination throughout the operation. In particular, he ensures that the battle is being shaped according to the plan. Therefore, in the center and right sectors where the battalions have been given a defend mission, he must be prepared to divert assets to augment their lethality. In this regard, the ground reserve must be prepared to block enemy penetrations or reinforce the defensive positions while attack helicopters may be called forward to inflict casualties in the depth of the EA.

As the covering force moves closer to the MBA, the brigade commander coordinates with his counterpart brigade commanders. The main CP and TAC CP collocate with the MBA brigade CPs in preparation for the rearward passage of lines. Maneuver elements from the MBA are alerted to cover the rearward passage of the covering force, and a battle handover line (BHL) is confirmed. The covering force fights and withdraws to positions within the protection of the MBA forces. At this point, massive combined arms fires should be brought to bear against the lead enemy elements. This temporary enemy paralysis should allow the complete passage of the covering force, free of significant enemy pressure and the intermingling of forces.

The artillery plan is executed in the same manner as in a defense or delay. A significant difference is that as the covering force moves closer to the MBA, the covering force fire support officer coordinates with the MBA brigade FSO for positioning of the covering force's DS battalions.

The covering force engineer monitors the operation, paying special attention to the execution of target turnover and brigade reserve demolitions. In particular, he advises the commander during the course of the battle concerning techniques to further slow enemy momentum if required. For example, he coordinates with the brigade FSO for the emplacement of ADAMs/RAAMs and with the S3 to ensure the obstacle is covered by fire. As the force moves closer to the MBA, obstacles take on increasing importance in helping the covering force maintain separation from the enemy. If the BHL is placed along a natural obstacle, such as a river, prepared bridge demolitions or armored vehicle launched bridge (AVLB) or heavy assault bridge (HAB) crossings sites should be monitored to ensure their execution following the crossing of the last maneuver element. Subordinate commanders report execution to the covering force main CP so that the brigade commander can verify the safe crossing of his maneuver elements and the inability of the enemy to maintain pressure.

The brigade S4 continually coordinates with the FSB commander to ensure that CSS operations are executed according to plan. He coordinates with the engineers to monitor the road conditions and the status of any bridges and coordinates for the implementation of on-order MSRs or other alternate routes depending on the situation. He also keeps abreast of the expenditure of Class III and Class V and of emergency resupply vehicles moving to units heavily involved in combat. As the covering force nears the MBA, the S4 also coordinates with the MBA brigade S4s. The control depends on the ability of recovery and evacuation assets to tow disabled vehicles to the rear and to keep the egress routes open. Assets from the MBA may assist in this effort, freeing the brigade's equipment for use in the forward area of the covering force battle.



As in all night operations, the night defense takes more time, detailed planning, preparation, rehearsals, and coordination than daylight operations.


The advantages and disadvantages of a defensive operation at night are parallel to those identified for night offensive operations in Chapter 4.


The following is a list of tactical planning considerations, by BOS, that are different for a night offensive operation when compared to a daylight offensive.


Assign scouts to assigned smaller, critical areas to observe, such as NAIs and TAIs.

Coordinate all reconnaissance activity in detail. This precludes friendly fire and fratricide between subunits. The FSO must also monitor calls for fire to prevent one unit from engaging another.

Increased use of remote sensors and GSRs covers areas no longer visible at night.


Security operations by all units is the key to maintaining the integrity of the defense. Night amplifies the defender's vulnerability.

Rehearse moving in darkness.

Set an observation plan for each EA, delineating what number and mix of observation devices are used.

Fire Support

Plan and support counterbattery fires to take away the use of illumination.

Survey and register final protective fires (FPF) in daylight.

Centralize authority for the use of illumination by weapon type and duration.

Smoke magnifies the effect of darkness on the attacker's formations and on his image intensification devices.

Adjustment of fires is inaccurate if only visual means are employed.

Mobility and Survivability

FASCAM is more effective at night; it can be emplaced rapidly and is difficult to spot.

Increase engineer work time as light decreases.

Provide engineers with security forces at night.

Sound travels farther at night. Use sound to deceive or cover by artillery fire.

Air Defense

Give assets point (critical) targets to defend, rather than area targets.

The pairing of systems with IFF capability with those that do not have it allows both systems to engage targets.

Combat Service Support

The threat to rear areas increases at night; therefore plan CSS accordingly.

Rehearse MEDEVAC routes in the dark.

Class I served between 0200 and 0400 hours counters the physiological "low" of the body.

Plan increases in supply rates for flares, illumination rounds, batteries, light sticks, smoke pots, wire, and general ammunition in advance.

Command and Control

Control measures are usually more restrictive at night. These include routes to and from BPs, light lines, and no-fire zones.

Wire is the preferred communications method, followed by messenger, radio, visual signals, and event-oriented plans.

Communications plans for recon teams must be rehearsed prior to sending personnel and equipment out.

Use GSRs to vector moving units, such as patrols, LPs/OPs, and scouts.

Forward to Chapter 6.
Return to Chapter 4.
Return to the Table of Contents.

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