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CHAPTER 5

Other Tactical Operations

Airborne, air-assault, and light infantry brigades conduct other tactical operations to support both offensive and defensive operations. In many cases, these operations are an inherent part of an offensive or defensive plan. In all cases, they require special engineer considerations during planning and execution. The brigade engineer and the company commander must have a fundamental understanding of other tactical operations and the special engineer requirements. The engineer missions involved in supporting other tactical operations are essentially the same as those outlined in Chapters 3 and 4. Furthermore, the principles of engineer C2 outlined in Chapter 2 still apply during planning and execution.

FORCE PROTECTION

Protection conserves the force's fighting potential so that it can be applied at a decisive time and place. Protection focuses on two areas:

• Conserving the force's ability to generate combat power.
• Denying the enemy the ability to generate combat power against the force.

Commanders implement force protection with a force-protection plan. A force-protection plan addresses all components of protection, including fortification, deception, countermobility operations, and protective obstacles. This plan includes both active and passive protective measures. While frequently applied in OOTW, force protection must be addressed in all levels of war, throughout the battlefield framework and during all types of operations. FM 5-114 outlines actual force-protection measures that the brigade and supporting engineer units may employ.

The brigade engineer and supporting company commanders are involved in the brigade's force-protection measures from two perspectives. They--

• The Provide input to the brigade's force-protection plan.
• Assist in the critical aspects of execution and the actual monitoring of the implementation of the commander's plan.

FUNDAMENTALS

The brigade's force-protection plan is developed in line with the brigade's decision-making process outlined in Chapter 2. The force-protection plan is--

• Developed by the combined arms brigade staff.
• Derived from force-protection guidance from the brigade commander.
• Based on the combined arms execution.
• Updated and revised continuously.

While force-protection planning and execution is a combined arms responsibility, engineer input and assistance are critical to its success. Specifically, planning engineer input with the S2 during the IPB process ensures that engineer intelligence needs are integrated into all reconnaissance and collection plans, intelligence requirements (IR), and PIR.

THE THREAT

Force-protection planning is threat based, keying on IPB/EBA. It is also balanced against available resources. The brigade plan focuses on trying to remain proactive, rather than reactive, to the potential attack. The ultimate goal of the force-protection plan is to balance the attack probability against the consequences of inadequate protection, with the cost (time and resources) for adequate protection (risk level).

Before developing the force-protection plan, engineer planners and executors must fully understand the threat as it applies to force protection. Only when the threat is understood by the brigade engineer and the company commanders can engineers play a significant role in protecting the brigade. Once the threat is understood and engineer forces supporting the brigade are given time and priority, they can assist the brigade in establishing effective protective measures.

The threat's tactics and methods are different, based on the regional AOs, the operational tempo (OPTEMPO), and the area within the battlefield framework. The threat and the process used to evaluate it, must be understood by the engineer.

The threat template developed during the S2's IPB is used as the foundation for the force-protection planning process and must be continuously reevaluated. This reevaluation occurs at either a set time (for example, every two hours) or a critical event (a change in the threat's tactics and weapons). If the reevaluation process of templating the threat does not occur, the commander's force-protection plan rapidly becomes static, and the brigade becomes reactive to the threat's attacks.

Aggressor Types

The threat is closely evaluated in terms of force protection to provide more detailed information to the initial threat template developed by the S2. The threat is categorized into four types of aggressors that engineers must understand so they can provide input to the brigade's force-protection plan. They are--

• Criminals.
• Protectors.
• Terrorists.
• Subversives.

See Figure 5-1 for a description of each type.

Aggressor Tactics

The threat employs a variety of tactics against the brigade. Any one or any combination of these tactics may be used. Also, the brigade may be faced with an evolving threat, employing tactics not listed in this chapter. Figure 5-2 lists various aggressor tactics.

Aggressor Attack Methods

The attack methods (weapons, tools, and explosives) used by the threat to accomplish its goals are as varied as the techniques and their application. Weapons may range from rocks and bottles to sophisticated guided systems used to attack targets. Tools are normally used in forced-entry operations to breach protective components or barriers. Explosives are commonly used to destroy facilities and kill personnel. Figure 5-3 lists some of the attack methods and describes their potential employment.

PLANNING PROCESS

The force-protection planning process is comprised of the following steps:

• Step One: Define the threat and attack probability.
• Step Two: Determine the composition of assets (personnel, equipment, and facilities).
• Step Three: Determine the level of protection required for each asset.
• Step Four: Design systems and activities to counter the threat.

Figure 5-4 shows how the force-protection planning process parallels the military decision-making process.

Step One

The results of this step are used to direct force-protection planning and design in step four. This step relies heavily on the IPB process already conducted during the decision-making process. It also provides the basis for step two, determining and evaluating enemy and friendly capabilities and vulnerabilities and potential COAs focused on the enemy's assault and potential attack of brigade assets. The bulk of the information is routinely derived from the DST and MCOO. Step one is a distinct process; however, it is ultimately performed simultaneously and continuously with the IPB process. This step has five parts as follows:

• Template the aggressor type and potential assault and attack methods. This information is an extension of the template and is normally compiled during the IPB process; it is focused on threat. Additional requests for information (RFIs) or PIR are routinely developed by the planning unit to fill specific information voids for protective-obstacle planning.
• Evaluate the terrain around the asset. The area surrounding the asset is evaluated against the templated aggressor and his ability to employ his preferred weapon, tool, or explosive. This evaluation helps determine the validity of the employment of any templated assault or attack method.
• Template potential assault and attack targets. This is derived from the aggressor template.
• Prioritize templated assault and attack methods based on the developed situational template (used in determining the protection level in step three).
• Prioritize templated assault and attack targets based on the developed situational template (used in step two). Which targets, or assets, within the brigade are going to pay the biggest benefit to the aggressor if they are damaged or destroyed?

Step Two

During this step of the force-protection planning process, commanders and staffs develop a comprehensive list of all units and systems that require protection.

A list is established, identifying the initial effort priority for each unit and system. Prioritizing the list helps the brigade engineer focus time and resources at critical units and systems that require engineer support. Initial-effort prioritization is based on the criticality and vulnerability of the unit or system being evaluated. This prioritization is verified during step three of the force-protection planning process when final guidance is received from the commander. Assets are normally assigned a numerical priority. Multiple assets can hold the same priority level.

Step Three

This step focuses on taking information collected and developed in steps one and two and applying it to determine protective levels. Once the levels are determined, staff planners design, position, and resource protective efforts. Step three is divided into two parts as follows:

• Determine the force-protection level required for each position. The criticality (to the brigade) of the asset and the likelihood of an attack and assault (the criticality of the asset to the threat) determine the protection level for each asset. Two primary components of force protection for the brigade are fortification effort and protective obstacles. These two building blocks are used to achieve the commander's directed force-protection level. There is normally a balance between protective-obstacle effort and the fortification effort available for the position. Determining the level of protective-obstacle effort required by a position is ultimately determined through the commander's guidance balanced against the directed level of survivability for units, personnel, and systems within the position.
• Determine for the brigade the force-protection level required to counter the threat. The staff determines the level of protection required and gives its recommendation to the commander. This is normally stated in terms of protection against a given method of attack. For example:

"All priority one assets (priorities established in step two) within the brigade are to be provided level two threat protection (first two templated threat attack methods, determined in steps one and two) within 72 hours. All priority two assets (within the BSA only) are to be provided level one protection within 72 hours and level two protection within 96 hours."

Step Four

This step focuses on the final design and resourcing of the force-protection plan. Once the level of protective effort is determined (step three), protective activities are determined, positioned (as required), and subsequently resourced. FM 5-114, Appendix A, addresses specific techniques to counter potential threats. The key to this step is ensuring that the planned protective efforts accomplish the following:

• Counter the templated threat.
• Do not significantly degrade any direct and indirect fires and observation.
• Support the commander's force-protection plan.

Force-protection planning and its execution are not one-time processes. They must be continually and systematically updated, depending on METT-T, force-protection status changes, and the commander's guidance. Figure 5-5 shows the force-protection planning process (its steps and actions to be taken). Figure 5-6 is an example of a matrix used to track force-protection planning and execution.

To ensure brigade-wide dissemination, the results of the force-protection planning process become elements of the brigade OPORD/operation plan (OPLAN). A statement/paragraph outlining the commander's intent for force protection can be addressed in paragraph 3 of the execution, in addition to a dedicated force-protection annex, as required.

MILITARY OPERATIONS ON URBANIZED TERRAIN

Operations in a MOUT environment are planned, coordinated, and executed in the same fashion as an operation in any other type of environment. Urbanized terrain does not change the nature of the operation, but it does cause the brigade engineer and the company commander to plan, coordinate, and execute using some additional considerations. Therefore, Chapters 3 and 4 of this manual contain the bulk of information and doctrine that the brigade engineer and company commander need.

BRIGADE ENGINEER

The brigade engineer performs the following when planning force protection:

• Secures blueprints of buildings; sewer, electrical, and water systems; and others.
• Determines the location of utilities (power, water, telephone system, mass transit hubs, and mass fuel locations).
• Determines the availability of HN equipment, construction materials, fortification resources, civilian work-force assets, and civilian subject matter experts (SMEs) (guides, electricians, and so forth).
• Determines the unexploded ordnance (UXO) characteristics in the AO (type, number, density, and location).
• Considers centralized planning and decentralized execution.
• Determines how the rules of engagement (ROE) affect engineer capabilities and missions.
• War-games engineer support during the following phases:

- Phase 1-Isolate the area.

- Phase 2-Control dominant terrain (no traffic/no resupply in or out).

- Phase 3-Seize a foothold.

- Phase 4-Clear the urban area.

• Establishes the following common obstacle-control measures:

- Obstacle marking.

- Obstacle lane marking.

• Establishes demolition blast signals (visual and audible).
• Establishes common route markings.
• Plans for security requirements to protect Class IV/Class V supplies and engineer equipment.
• Ensures that engineers breach/reduce tactical obstacles and the infantry breaches/reduces protective obstacles.
• War-games SOSR in MOUT and ensures rehearsals.
• Plans for mobility teams (task-organized based on METT-T). SMEs educate infantry on obstacle breaching techniques.
• Plans in three dimensions (above ground, ground level, and below ground).
• Plans an engineer contingency mission for EOD.
• Plans for a hasty defense.
• Plans for follow-on engineer requirements.
• Plans and resources route-clearance operations.
• Addresses special obstacle-reduction requirements.
• Addresses and requests EAD engineers to support brigade general engineering tasks.
• War-games and plans for the contingency of MOUT-peculiar follow-on mission requirements.
• Addresses and resources the increase of demolition and Class V requirements in MOUT.
• Plans for additional "bunker-busting" capabilities (AT-4, shoulder-launched, multipurpose assault weapon (SMAW), and so forth).
• Requests the following special MEE:

- 120-foot rope.

- Grapnels.

• Plans for the procurement of the following additional materials (locally fabricated, if required).

- Satchel charges (field expedient, if not available).

- Rope ladders/ladders.

- Marking materials (paint, chalk, engineer tape, and chemical lights).

- Bangalore torpedoes.

- Fragmentation/concussion grenades.

• Disseminates booby-trap neutralization equipment and techniques (special RFI) to higher or sister brigade.

COMPANY COMMANDER

The company commander performs the following when planning force protection:

• Identifies special equipment needs for the platoons.
• Plans for continuous resupply of engineer-specific logistics, especially demolition.
• Ensures that combined arms rehearsals are conducted for all operations.
• Teaches infantry demolition and breaching techniques.
• Plans for decentralized operations (team leader level).
• Ensures that every soldier understands ROE and how they affect engineer support of the operation.
• Works closely with the brigade engineer during the planning process.

RETROGRADE OPERATIONS

A retrograde operation is an organized and orderly movement of forces to the rear or away from the enemy. The rearward movement may be forced or voluntary; how ever, in either case, the division commander has authorized it.

TYPES

The basic types of retrograde operations are--

• Delay.
• Withdrawal.
• Retirement.

All three types are usually combined in simultaneous or sequential action. For example, a battalion TF may conduct a delay to facilitate the rest of the brigade's withdrawal or retirement.

Delay

The intent of a delay is to slow the enemy, cause it casualties, and stop it (where possible) without becoming decisively engaged. The brigade accomplishes this by defending, disengaging, moving, and defending again. The concept of the operation for a delay frequently requires offensive operations (counterattacks/spoiling attacks) on the part of the delaying force.

Withdrawal

The intent of a withdrawal is to allow the brigade to disengage from the enemy and reposition itself for some other mission. That mission may be to--

• Delay the enemy.
• Defend another position.
• Attack at another place and time.

The two types of withdrawals are-

• Under pressure. The brigade disengages and moves to the rear while in contact with the enemy.
• Not under pressure. The brigade disengages and moves to the rear while the enemy is not attacking.

Retirements

A retirement is a retrograde operation in which the brigade, while not in contact with the enemy, moves to the rear in an organized manner. Tactical movement techniques are employed as well as foot marches and vehicular road marches. Retirements may follow withdrawals, or they may begin before contact is made with the enemy.

ENGINEER SUPPORT

The underlying purpose of engineer support to retrograde operations is twofold. First, the mobility of the brigade must be maintained regardless of the type of retrograde operation being conducted. Mobility operations focus on maintaining the ability of the force in contact to disengage while preserving the main body's freedom of maneuver. Second, the force must be protected during its retrograde. Light infantry forces are particularly vulnerable to enemy actions during retrograde operations. For this reason, they are normally conducted under limited visibility conditions. Engineers provide survivability for units left in contact and extend the time available to the brigade commander by reducing the enemy's mobility through obstacles, fires, and terrain.

The focus of engineer support to retrograde operations is normally countermobility and mobility operations. The actual priority of support depends on whether or not the brigade is in contact with the enemy. The planning considerations laid out in the following paragraphs apply equally to any of the retrograde operations. They require the application of METT-T to determine the prioritization of engineer mission support.

Staff Planning

Engineer involvement in the staff planning process for a retrograde is critical. Because of the up-tempo of the operation, all contingencies are to be addressed, war-gamed, prioritized, and resourced before execution. The tactical situation normally does not facilitate any significant changes to a plan once the operation is under way. Of special importance is the engineer's involvement in the IPB process. The level of detail developed by the staff and notably the engineer planner affects resourcing, task organizations, and ultimately execution.

During brigade retrograde operations, the brigade engineer coordinates with the S2 on engineer-specific PIR. These PIR are aimed at facilitating and maximizing the efforts of engineer units conducting the counterreconnaissance fight and retrograde. Considerations include the templating of enemy reconnaissance and main-body attack routes into the brigade sector. These considerations aid in the planning and execution of obstacle belts supporting the retrograde by the brigade.

Vital to all retrograde operations is the identification of routes to be used by the brigade. While conducting the terrain analysis during the IPB process, the brigade engineer works closely with the S2 to determine feasible routes. Once complete, these routes are coordinated with the brigade S3 and the commander to determine the actual routes that meet operational requirements. Once routes are identified, engineers conduct route reconnaissance to verify their trafficability and suitability for the brigade. Information gained on the reconnaissance is critical to the brigade staff during COA development and analysis.

The brigade engineer's involvement in the IPB process is vital to the retrograde. As laid out in Chapter 4, the end result of the brigade engineer's input into the MCOO is the determination of the effects the terrain will impart on the attacking enemy. Once determined, this product of the terrain analysis impacts the--

• Positioning of obstacle belts.
• Positioning of decision points to assist in lane closure.
• Execution time of situational and reserve obstacles.

Countermobility

Countermobility planning for retrogrades is normally conducted centrally by the brigade engineer. However, execution is normally decentralized; it is conducted only with a clear understanding of the commander's intent and concept of the operation. A major component in countermobility planning and execution during a retrograde operation is the synchronization of all the BOSs.

Situational obstacles provide a key combat multiplier to the commander. For the light force, FASCAM obstacles are the predominant type, providing the commander maximum flexibility. Situational obstacles are planned predominantly against the most likely or the most dangerous AAs (where executed obstacles are not feasible). Situational obstacles, like other engineer operations in retrogrades, are normally centrally controlled.

Lane Closure

C2 of lane closure is vital to the brigade's retrograde. Normally, lane closure is centrally resourced, planned, and executed by the brigade to ensure that mission execution is in line with the commander's intent. Frequently, obstacles identified for closing lanes become the brigade's reserve obstacles. Lane closure depends on the--

• Enemy and friendly activity.
• Level of contact.
• Size of the force left in contact.
• Engineer forces available.

Lane-closure parties (engineers if METT-T allows) close lanes upon notification from the commander to whom execution authority was delegated (the maneuver force overmatching the obstacle). Synchronization is critical to prevent the trapping of friendly forces between the obstacle and the enemy. Target turnover becomes important when reserve targets are prepared by engineers and turned over to the infantry for execution. Target turnover and its execution must be detailed so that an infantry unit (platoon or squad leader) can execute the mission according to the commander's intent. All lane-closure operations must be rehearsed.

Mobility

The brigade usually has a mobility advantage within its sector on interior LOC. This advantage must be capitalized on and maintained, by proper and timely use of engineer assets during the operation. One of the steps required during retrograde planning is the identification of routes. The size, location, and type of routes selected has significant impact on engineer support. Route selection impacts countermobility planning and execution as well as mobility operations.

Once the routes are finalized, the company commander is responsible for ensuring that they are upgraded and maintained as directed. LOC maintenance frequently requires nondivision engineer assets and support. Lanes through friendly obstacles must be established and marked. Every soldier in the brigade must clearly understand the brigade's lane-marking system. Guides are frequently left at obstacle-lane locations to ensure safe passage. Because of the critical nature of the mission, consider allowing engineers to assume the responsibility of providing guides, if METT-T allows.

Aviation

Army aviation units use retrograde operations to reposition units and to attack enemy forces, providing additional time for the maneuver force to disengage. Engineers support the aviation units through FACE operations and obstacle emplacement. Detailed planning between aviation units supporting the brigade and the BMEC is critical to the synchronization of this effort.

Battlefield Deception

Deception operations target the enemy force to cause indecision and to prevent it from concentrating combat power at a friendly force's weakness. The brigade engineer coordinates with the S2 and the S3 during initial planning to determine what battlefield deception assets are available. For example, a tank silhouette that is partially dug in may cause the enemy to think the friendly force is defending instead of conducting a retrograde operation.

At the engineer company level, not only can countermobility operations shape the battlefield, but they can also deceive the enemy as to what mission the brigade is actually conducting. For example, utilizing engineer equipment forward gives the appearance of preparing for a hasty defense while covering the withdrawal of a force.

Combat Service Support

Even though the unit is conducting a retrograde operation, some engineer assets and supplies may be moving forward. The brigade engineer is responsible for deconflicting these movements. This is accomplished by coordinating with the brigade S4 on the following issues:

• Some engineer equipment cannot keep up with the brigade's trains and must be hauled using transportation assets. To meet this requirement, transportation assets may have to come from the division.
• Engineer Class V supplies need to be brought forward and rearward. Mines need to be positioned at obstacle lanes so they can be closed
• Fuel requirements for forward heavy engineer equipment increase if the equipment is working in support of the retrograde operation. This fuel must be identified, like all other classes of sup. ply, before it is moved to the rear.

PASSAGE-OF-LINES OPERATIONS

A passage of lines is an operation in which one force moves (forward or rearward) through another. Engineer considerations for each are similar and depend on whether the brigade is the passing force or remains in place. Primary considerations that impact planning for a passage of lines are the--

• Passage of engineer control.
• Exchange of information.
• Mobility of the passing force.

The passage of control between passing and in-place brigades is one of the key considerations in any passage of lines. The commanders of the in-place and passing brigades must establish a mutually agreed upon event that triggers the passage of control. During a forward passage of lines, control of the battle is given to the passing brigade once it is committed to the passage routes or corridors. Once control is passed, the passing brigade exercises tactical control (TACON) over the in-place brigade until all of its forces are beyond the direct-fire range of the in-place brigade. During a rearward passage of lines, however, control is passed from the rearward-passing unit to the in-place brigade unit. Forces in the rearward-passing brigade turn over TACON to the in-place brigade once they are committed to the passage routes or corridors.

The brigade engineers must have a thorough understanding of when functional and unit control is passed and the disposition of engineer forces and missions at the time of passage. When control is passed between the brigades, the corresponding brigade engineer assumes TACON (through the TACON commander) of all engineer forces of the passing and in-place brigades. The controlling brigade engineer can then recommend mission assignments to the TACON commander for engineers of the adjacent brigade based on immediate requirements during the passage. This is critical during the forward passage of lines since it provides the passing brigade engineer a means of accomplishing unforeseen engineer tasks with minimal impact on engineer support to the subsequent attack.

Close coordination between brigade engineers is critical to the success of the passage of lines. The brigade engineers of both the passing and in-place brigades collocate during the planning and execution of the operation. They initially focus on the exchange of information on--

• Zones established by the division.
• Locations of established belts, groups, and individual obstacles.
• Details of reserve obstacles.
• Situational-obstacle planning and resourcing.
• Routes through the brigade sector.

The passing brigade engineer then ensures dissemination of the information to subordinates through coordination with the brigade S3 and instructions in the brigade OPORD, engineer annex, and engineer overlays.

Whether conducting a forward or rearward passage, the in-place brigade is responsible for providing mobility for the passing unit along cleared routes or corridors through its sector. The in-place brigade engineer conducts a complete analysis of the passage-of-lines concept of operations. The in-place brigade normally tasks subordinate maneuver units to prepare the routes or corridors. The brigade engineer recommends task organization for engineer forces within the brigade, based on the assets needed to clear assigned routes and corridors. Clearing operations must be completed before the initiation of the passage. Additionally, the passed brigade engineer must plan the method for the closure of lanes through obstacles, if required, once the passage is complete.

The passing unit organizes for in-stride breaching operations before initiating the passage of lines. This is to ensure rapid support for mobility operations and continuation of the passage in the event a route is shut down during the mission. Creating lanes through the in-place unit's obstacles requires permission from the brigade exercising TACON. Authority to reduce friendly obstacles in response to an immediate tactical situation may be given to subordinate units. The authority is included in the coordinating instructions of the brigade's OPORD. Under all circumstances, this action must be reported to the passed unit so that the obstacle can be repaired. The brigade engineers must closely monitor the passage during execution to advise the respective brigade commanders on the impact of such occurrences.

C2 of both the passed and passing unit engineers during the passage of lines is also transferred to the brigade that is exercising TACON. That brigade engineer must facilitate control of the engineer units during planning and execution of the passage of lines by having an accurate status of all engineer assets, activities, and obstacle-control measures in the sector. This includes the status of all reserve targets and situational obstacles, including the execution criteria for each.

The following coordination considerations are for the brigade engineers of the passing and in-place brigades:

• Types of information exchanged between the brigade engineers are as follows:

- Obstacle overlays (planned, prepared, and executed).

- Class V stockpile, locations, types, and quantities.

- Routes and lanes (alternates, limitations, and restrictions).

- Obstacle and lane marking and guide positioning.

- Enemy engineer assets, capabilities, and recent activity as templated.

- Friendly unit assets, capabilities, and limitations.

- Communication (frequency, variable, challenge/password, and so forth).

- Date, time, and location for engineer key leader rehearsals.

• Brigade engineer execution checklist for in-place units is as follows:

- Coordinate with the S2 for the counterreconnaissance fight.

- Rehearse with all key engineer leaders.

- Place guides.

- Specify obstacle lane-marking procedures and logistics.

- Complete mobility requirements (brigade rear to brigade front) before passage initiation (reconnaissance and route maintenance).

- Plan for lane closure once the mission is complete.

- Coordinate for prestocked Class IV/Class V supplies at lane locations.

- Report engineer assets, capabilities, and limitations to the brigade engineer of the passing unit.

- Disseminate the communications plan.

• Brigade engineer execution checklist for passing units is as follows:

- Rehearse with all key engineer leaders.

- Task-organize mobility teams to support the main effort (METT-T).

- Be prepared to assume TACON of engineer responsibilities.

- Maintain the current status of both brigades' assets, abilities, and limitations.

- Disseminate the communications plan.

RELIEF AND LINKUP OPERATIONS

A relief operation is a combat operation in which all or part of a unit is replaced with another unit. The two types are--

• Relief in place

- Units are similar in size.

- Defensive operations continue.

• Area relief.

- Units are dissimilar in size and/or table of organization and equipment (TOE).

- Defensive needs are improving or unit expects a change of mission to offensive operations.

Engineer requirements remain essentially the same for either type of relief operation; however, turnover of obstacles, particularly reserve targets, are more difficult and time consuming during an area relief operation. This is especially true if a smaller-size unit is replacing a larger element.

Linkup operations are conducted to make physical contact between two forces to conduct future operations. Both forces may be moving toward one another, or one may be stationary or encircled. Linkup operations may be conducted in a variety of circumstances. They are most often conducted to--

• Complete the encirclement of an enemy force.
• Assist the breakout of an encircled friendly force or an attacking force with a force inserted in the enemy rear.

Engineer-specific issues and tasks are similar for both relief and linkup operations.

PRINCIPLES

The following key considerations are used in planning and executing a relief operation:

• Security.
• Speed.
• Control.

Security

Because of the inherent vulnerabilities created by a relief operation, it must be concealed from the enemy for as long as possible. Deception and operational security (OPSEC) are both important from the outset.

Speed

Once a relief operation begins, it is extremely vulnerable to being spoiled by the enemy. Unnecessary delays during execution must be avoided to prevent giving the enemy time to acquire a target and mass fires.

Control

Control is the most important relief operation principle. Intermingling forces place increased demands on brigade C2, particularly if enemy contact is made during the operation.

ENGINEER SUPPORT

Engineers contribute most to a relief operation by assisting the brigade in achieving speed and control. Therefore, these two principles become the focus of the brigade engineers of the relieved and relieving units during planning and execution. Both brigade engineers must work together to develop a unified scheme of engineer operations. They must fully understand the entire scope of the mission, to include the defensive plan and the concept for the relief. This helps the brigade engineers identify the engineer tasks that must be accomplished to maintain speed and control during the operation.

Engineers facilitate the brigade's requirement for speed in two ways. They--

• Provide mobility to both the relieved and relieving units.
• Expedite obstacle turnover.

The brigade engineers for both units must develop engineer task organizations that meet the needs of the TF's mobility requirements. Brigade engineers also facilitate speed through a rapid but complete obstacle turnover. Obstacle location, configuration, and composition are consolidated and provided to the relieving unit. Reserve targets and situational-obstacle information are also included in the turnover. Additional information may include choke points, route reconnaissance, engineer estimates, location of HN engineer assets, and engineer-specific coordination with flank units.

Brigade engineers assist their respective brigade's control of the relief operation by--

• Providing detailed mobility planning.
• Developing a detailed obstacle-turnover plan.
• Providing LOS to maintain engineer continuity during the relief.

When planning mobility operations, the brigade engineers review the relieved unit's defensive plan overlaid with the relief operation concept. Routes for the entering and exiting units must be clearly identified and marked; guides may be needed. The brigade engineers determine the mobility tasks that must be accomplished on each route. The relieved unit prepares the routes through its sector for the relief operation. Depending on METT-T, both brigades may need to plan to use mobility teams during the operation.

When developing the obstacle-turnover plan, the relieved brigade engineer must have a detailed and current status of each obstacle in his sector. An individual obstacle list and a complete obstacle overlay must be handed over to the relieving brigade engineer. This may also include the turnover of HN assets, barrier materials, and engineer estimates of the AO. TF engineers are responsible for the same level of coordination with the relieving TF engineers, which is then verified by the company commander. This process ensures the redundant flow of information, facilitating a difficult and detailed operation. The brigade engineers must also determine how to exchange reserve obstacles and situational-obstacle plans.

If supported by METT-T, the presence of engineer LOS (engineer squad level) at the infantry company level can greatly enhance the speed and control of obstacle turnover. Upon linkup, engineer LOS with the relieving units become familiar with the existing obstacles, terrain, and direct-and indirect-fire control measures that are integrated into the obstacle plan. Rapid, efficient turn-over is critical for two reasons. It--

• Ensures that the maneuver commander is immediately capable of using the existing obstacles as a combat multiplier in defeating the enemy.
• Expedites the shifting of engineer effort from obstacle turnover to improving the unit's defensive posture or preparing for a future attack.

Most relief operations occur when a unit is in either a hasty or deliberate defense. Light forces have the inherent requirement to conduct relief operations while the relieved unit is not in a defense. This usually takes place when a light force is relieving another light force while securing a lodgment (either a forced entry or an unforced entry) on an airfield, a port facility, or a combination of the two. An example of this is a brigade of the 82d Airborne Division relieving the 75th Ranger Regiment during an airfield seizure mission, followed by elements of the 10th Mountain Division relieving the 82d Airborne Division. When a light unit relieves another light unit, it is essential that the level of threat expected by the relieving unit is accurately templated and that preparations are made accordingly. An initial brigade R& S plan is prepared at the home station, and refinements are made to it from information received during the initial liaison. Relieving units that are seizing/securing a key facility have some special engineer considerations that differ from the hasty or deliberate defense.

AIRFIELD RELIEF OPERATIONS

Airfields are critical for sustainment of light forces. Once the lodgment is established, the engineers' most important mission is to make the runway operational and maintain it so that the air-land flow is uninterrupted. To effect this, the brigade engineer collocates with the brigade-level CP that controls the airfield (normally an assault CP from the brigade assault force). Coordination is also conducted with the Air Force combat control team (CCT) representative on the airfield. The brigade engineer obtains the following information from these individuals:

• Status of the airfield, to include the minimum number of operating strips; the maximum number of on-ground aircraft that the airfield can currently and eventually hold; any known damage to the runway, taxiway, and parking apron; work estimates to get the airfield operational; and any scheduled maintenance being conducted to keep the airfield operational.
• Status of the airfield facilities, to include the control tower, hangars, electrical power, runway lights, and bulk-fuel locations.
• Availability and location of HN support, to include hauling and off-loading assets and engineer equipment.

PORT-FACILITY RELIEF OPERATIONS

A port-facility relief operation is similar to an airfield relief operation. However, instead of receiving aircraft, the unit receives ships, and instead of being relieved by light forces, the unit is probably relieved by a heavy force (Marine amphibious force (MAF) or Army mechanized unit). The brigade engineer should consider the following:

• Status of the port and facilities, to include an estimate of the water depth (divers may be needed), available docking sites, and off-loading equipment (cranes).
• Availability of HN equipment and personnel support to facilitate the off-loading of equipment.
• Status of port damage, current port repair, and maintenance operations.

RIVER-CROSSING OPERATIONS

Normally, light infantry brigades do not conduct river-crossing operations without extensive EAD augmentation, including additional EAD engineers (such as tactical bridging units). However, light infantry brigades may be tasked to support a crossing as part of a larger division or corps operation where a light division is moving into an area to allow heavy units to continue the attack across a river and beyond. It may also support an infiltration operation focused at supporting a larger force's crossing operation.

River-crossing operations fall into three categories:

• Hasty.
• Deliberate.
• Retrograde.

Deliberate river-crossing operations are covered in this chapter as a worst-case scenario for light engineer support. FM 90-13 contains additional information on deliberate river-crossing as well as a discussion of the hasty and retrograde river-crossing methods.

A deliberate river crossing is an attack that is planned and carefully coordinated with all concerned elements. It is based on--

• Thorough reconnaissance.
• Evaluation of all intelligence and relative force ratios.
• Analysis of various COAs.
• Other factors affecting the situation.

A deliberate river crossing requires extensive planning, detailed preparation, and centralized control. It is usually conducted against a well-organized defense when a hasty river crossing is not possible or has failed. This type of river crossing requires the sudden, violent concentration of combat power on a narrow front, in an area where there is a high probability of surprise.

A deliberate river crossing supports the tactical plan in four phases:

• Advance to the river.
• Assault across the river.
• Advance from the exit bank.
• Secure the bridgehead line.

Light units may serve as the river-crossing assault force in conjunction with air-assault operations behind the enemy's defenses on the river. Once the far side of the river is cleared, rafting or bridging operations can begin. The actual crossing operation is often planned and executed by the brigade XO and staff. In this capacity, the brigade XO is the crossing-area commander.

The first two phases of the deliberate river crossing use control measures through assembly areas and holding areas (see Table 5-1). These control measures pertain only to a small-boat assault by light forces.

The only light engineer river-crossing capability for vehicles and equipment would be through the identification and construction of fords. The final two phases beyond the river crossing require engineer support for offensive operations. The engineers supporting this requirement should be independent from the crossing engineers. Chapter 3 covers the planning and execution for offensive operations. Table 5-2 gives some planning considerations for the brigade engineer and the company commander.

REAR-AREA OPERATIONS

The brigade rear is that area from the TF's rear boundary to the brigade's rear boundary. Brigade rear operations are designed to ensure freedom of maneuver and continuity of operations, including sustainment and C2. Brigade rear operations normally have little immediate impact on current close ground operations but are critical to subsequent operations.

Reserve forces and CS and CSS units are located in the rear area. The BSA, FOBS, FARPs, artillery fire bases, and TF combat and field trains may be positioned in the brigade rear area. Engineer support of rear-area operations may require additional engineer assets. These assets need to be requested from the corps through the division. Adequate engineer support of rear-area operations requires detailed planning and coordination by both the brigade engineer and the company XO. The company XO also acts as the BSA engineer.

Rear-area engineer operations, if neglected, may cause the maneuver plan to fail. Therefore, rear-area engineer operations must be planned and executed to sustain the combat power of the light infantry brigade and to allow the brigade to provide needed support to its TFs.

MOBILITY

The brigade engineer addresses rear-area operations during the IPB process. As the terrain expert, he determines possible rear-area-unit locations from a mobility and countermobility support standpoint. Direct coordination between the brigade engineer, the BREC, the brigade S3, and the brigade rear CP results in rear-area-unit locations that are both operationally sound and traffi-cable, The brigade engineer must also coordinate with the brigade S3 and S4 to ensure that trafficable and easily maintainable MSRs are identified in the brigade's OPORD.

The brigade engineer also plans route-reconnaissance and route-clearance operations and MSR maintenance, Reconnaissance of initial MSRs must be done by engineers so they can be validated for use by the brigade's support vehicles. The initial reconnaissance gives the brigade engineer and the company commander an initial work estimate for repair and maintenance of the MSRs.

After the initial review of the IPB process, particularly the enemy templating process, the brigade engineer can deter mine how frequently route-clearance operations are needed to keep the MSR open. The frequency can range from an initial route clearance to task-organizing a route-clearance team with each convoy that travels on the MSRs. This frequency depends on the enemy's assets and capabilities and the current level of threat. During engineer-intensive operations (for example, defense), the brigade may need additional engineer support (corps engineers) to adequately conduct these missions.

SURVIVABILITY

During rear-area operations, engineers focus on force-protection support to units in the rear area. FM 5-114 covers the levels of support, as do Chapters 3 and 4 of this manual. The brigade rear area consists of key maneuver brigade elements and support units that need survivability positions constructed by engineer units. Some of the areas needing emphasis are the BSA, FOBS, FARPs, artillery fire bases, and TF field trains.

Unit operations officers have staff responsibility for their units' force-protection planning from two perspectives. They--

• Prepare their unit's force-protection plans (according to the brigade rear CP).
• Provide input (and capability) to the unit they are supporting.

As with other missions, engineer force-protection planning must be well thought out, logical, and integrated with other staff planning. Force-protection plans or policies are developed in line with the command estimate process, with the overall force-protection policy and plan being the responsibility of the brigade commander. The level of threat established during the IPB is the key factor in determining the amount of force protection the brigade rear area requires. The engineer must be involved with the IPB process to ensure that engineer intelligence needs are integrated into reconnaissance and collection plans, IR, and PIR.

COUNTERMOBILITY

All rear-area units are required to emplace protective obstacles around their perimeters to prevent enemy infiltration their base camps. The brigade engineer plans tactical obstacles to support the commander's force-protection plan. Engineers may be required to provide SMEs to individual units to construct protective obstacles; however, the engineers are not responsible for the obstacle construction.

GENERAL ENGINEERING

The maneuver brigade relies on the engineers to improve base camps and for the overall sustainment of other sites in the brigade rear area. Time and materials available, the degree of support, and the specific threat in the rear AO determine the sustainment requirements.

AREA DAMAGE CONTROL

The brigade engineer develops plans for--

• Assessing or estimating damage.
• Clearing a damaged area.
• Reconstructing and/or rehabilitating an area if damaged by either friendly or enemy activity.

Divisional light engineers normally require external support from EAD engineer units to execute ADC missions.

MOUNTAIN OPERATIONS

Operations in mountainous terrain require special equipment and training and acclimatization, along with a high degree of self-discipline, if they are to succeed. These operations are planned, coordinated, and executed in the same fashion as an operation in any other type of environment. Planning considerations outlined in Chapters 3 and 4 apply. Because of their adaptability and tactical mobility in restrictive terrain, light forces are frequently in this environment. The brigade engineer and the company commander should take into account the following special considerations when planning operations in mountainous terrain:

• LOC are typically inadequate in quantity and capacity; therefore, significant engineer equipment augmentation to construct and upgrade the LOC is essential. Consider task-organizing engineer heavy equipment forward to ensure that mobility is not hindered and that LOC are well maintained. Rockslides and mud slides can present a considerable obstacle in the mountains.
• Construction time for field fortifications and obstacles (particularly above the timberline and in rocky areas) or during periods of extreme weather may be significant. Resupply assets are constrained because of the terrain. Considerable time and equipment may be required to emplace these field fortifications because of the rocky ground. In extreme cases, extensive use of demolitions may be necessary.
• Stream crossings are frequent and difficult (particularly during the rainy season or spring thaw) and are usually accomplished by expedient means.
• In extremely rough terrain, cableways and tramways offer an effective means of supplying an attack and evacuating the wounded.
• Standard military bridging should be on hand to reinforce existing bridges that typically have low military load classifications.
• Helicopters play a key role in most mountain operations (both maneuver and logistics support). This makes it necessary for engineers to clear and level LZs, PZs, and FARPS. Nevertheless, the low-density altitude and extreme weather can significantly reduce the effectiveness of helicopters, resulting in an increased reliance on ground LOCs.
• METT-T may dictate increased decentralization of light engineer assets since mountainous terrain requires small-unit decentralized operations.
• Additional items (such as compressors, power drills, chain saws, and bulldozers) may be necessary to operate efficiently. Large amounts of explosives and obstacle materials may also be required.
• Enemy minefield are typically sited at choke points where the bypass is difficult or impractical; therefore, the scouts should be augmented with engineers to enhance the brigade's ability to collect engineer IR (for example, provide detailed minefield reconnaissance).
• SCATMINES are extremely effective for isolating most objectives because of the limited LOC available to the enemy.
• Engineer reconnaissance should precede all operations since maps are inadequate; however, it should not delay operations. Aerial reconnaissance and the division terrain-analysis team should be used to the maximum extent.

JUNGLE OPERATIONS

The brigade engineer and the company commander should consider the following when conducting operations in support of the brigade in jungle terrain:

• Road construction in the jungle is usually affected by poor drainage, heavy rainfall, and poor subgrade foundation. These problems can be dealt with by--

- Avoiding low ground for road construction.

- Laying long sections of pontoon bridging or corduroy or chess palling road through low swampy ground.

- Making roads wider, which thins the overhead foliage, so that the sunlight dries out the road.

- Using subgrade materials to support heavy traffic.

- Using runway matting or paving on roads to control erosion during the rainy season and dust during the dry season. Lime stabilization is also a field expedient method of stabilizing wet soils.

• It is essential that the infantry provide security to engineers performing missions.
• Operations in the jungle include--

- Clearing vegetation with engineer equipment to provide unobstructed fields of fire around fixed facilities.

- Requesting augmentation engineers to clear vegetation back 100 meters from MSRs; this greatly discourages insurgent mining and ambush operations. Paving the roads also significantly hampers insurgent mining operations.

- Tasking engineer teams to habitually clear the same route. This enables them to become intimately familiar with the route and to locate recently emplaced mines and booby traps.