Military

CHAPTER 4

DEFENSIVE OPERATIONS

The immediate purpose of any defensive operation is to defeat an enemy attack. Military forces defend until they gain sufficient strength to attack. Additionally, defensive operations are undertaken to gain time, to hold key terrain, to preoccupy the enemy in one area so friendly forces can attack elsewhere, and to erode enemy resources at a rapid rate while reinforcing friendly operations.

CONTENTS

SECTION I. Fundamentals of the Defense
SECTION II. Planning
SECTION III. Preparation
SECTION IV. Execution

Section I. FUNDAMENTALS OF THE DEFENSE

Characteristics of the Defense

FM 100-5 describes several characteristics of an effective defense: preparation; security; disruption, mass, and concentration; and flexibility. To optimize these characteristics in the defense, the tank platoon leader must consider the following factors.

Preparation

The critical element affecting preparation is time management, begin ning with receipt of the WO, OPORD, or FRAGO. Effective use of the available time allows the platoon leader to conduct a thorough reconnaissance of engagement areas, BPs, displacement routes, and the axis for possible counterattacks. Section III of this chapter describes preparation at the platoon level in detail.

Security

The OPSEC measures discussed in Appendix C will assist the platoon leader in maintaining security during the planning, preparation, and execution of the defense. The platoon leader must integrate his security plan with that of the company. He enhances the platoon's early warning capability by identifying potential mounted and dismounted avenues of approach and then positioning early warning devices and OPs to cover these avenues.

Disruption, Mass, and Concentration

Augmenting the platoon's direct fires with reinforcing obstacles and indirect fires is a key step in disrupting enemy operations. Platoons achieve mass and concentration by maximizing the number of tanks that can fire into an engagement area or that can move from primary positions to alternate and supplementary positions to concentrate fires on the enemy.

Flexibility

The platoon leader contributes to the flexibility of company operations by developing a thorough understanding of the company plan, including on-order and be-prepared missions. He must be alert to any possible contingencies that have not been addressed by the commander. During
the preparation phase of the defense, the platoon increases flexibility
by conducting thorough reconnaissance and mounted rehearsals of all possible plans. A crucial indicator of the platoon's flexibility is its ability to move quickly, and under all battlefield conditions, between primary, alternate, and supplementary fighting positions as well as subsequent and supplementary BPs.

Defensive patterns

The two patterns described in FM 100-5 are mobile and area defenses. A mobile defense is executed to destroy the attacking force by permitting the enemy to advance into a position that exposes him to counterattack by a mobile reserve. The focus of area defenses is on retention of terrain; defending units engage the enemy from an interlocking series of positions and destroy him, largely by direct fires. In support of mobile and area defensive operations, a company team may be tasked to execute one or more of the following missions and tasks: defend BPs, defend in sector, defend a strongpoint, counterattack, screen, delay, execute a reserve mission, and withdraw.

Role of the Tank Platoon

Section II. PLANNING

The planning phase of a defensive operation is a continuous process that begins when the platoon leader receives the higher order (WO, FRAGO, or OPORD). It ends when the platoon leader issues his own OPORD or FRAGO. Planning may continue into the preparation phase as the platoon gains more information through the higher headquarters plan and from further reconnaissance and rehearsals.

Ideally, the platoon leader takes part in two reconnaissance operations during the planning phase. He is normally part of the commander's
reconnaissance, along with the XO, other platoon leaders, the FIST, and the 1SG. The platoon leader's own reconnaissance includes his TCs and PSG. To save time, the commander and platoon leader attempt to issue their OPORDs or, as a minimum, a detailed WO during the respective ground reconnaissance operations.

During the commander's reconnaissance, the platoon leader must identify, record, and mark the tentative TRPs, decision points, fighting positions, and routes he thinks the platoon will use in executing the defense. It is important for him to have sufficient day and night marking materials such as engineer stakes and tape, chem lights, or thermal paper. He records the eight-digit grid coordinates of each position; this will allow him to provide precise locations that the platoon can use in navigation or orientation. Ideally, the platoon leader can record positions electronically using a hand-held GPS or the POSNAV system; if neither is available, he must rely on his map-reading skills to manually identify and record accurate position locations.

As planning progresses, it is important that the platoon leader make a careful evaluation of the following considerations based on the BOSs.

Intelligence

Security decisions are based on enemy capabilities. Platoons use OPs to provide early warning of the enemy's actions; their REDCON status and other OPSEC preparations then enable them to respond in a timely manner. See Appendix C for more information on OPSEC measures.

OPSEC is especially critical during the platoon leader's ground reconnaissance. The platoon leader ensures that he provides security for the reconnaissance based on the commander's guidance. Because it is probable that enemy elements are already in the area, he must ensure that platoon reconnaissance elements have the capability to protect themselves effectively.

As he conducts the reconnaissance, the platoon leader orients his map and references graphic control measures to the terrain. He conducts a terrain analysis, using the results in conjunction with his knowledge of possible enemy courses of action to identify key terrain that may define potential enemy objectives. He identifies mounted and dismounted avenues of approach and determines the probable formations the enemy will use when occupying support by fire positions or when assaulting the platoon's position. Based on his analysis and available fields of observation and fire, the platoon leader confirms vehicle positions that will allow the platoon to mass fires into the company engagement area.

The platoon leader should complete his reconnaissance by conducting initial coordination with adjacent platoons to establish mutual support and to cover dead space between the platoons. At the conclusion of the reconnaissance, he may leave an OP to report enemy activity in the area of operations.

Command and CONTROL & Maneuver

The platoon leader must understand the company plan and decision points; he develops his plan based on these factors as well as the commander's intent. The commander normally determines operational considerations such as OPSEC, occupation of firing positions, initiation of direct fires, primary and supplementary platoon sectors of fire, and disengagement criteria; however, he may allow the platoon leader to make decisions covering some or all of these areas.

The primary concern in selecting fighting positions is the platoon's ability to concentrate and mass lethal fires into its sectors of fire. Whenever possible, primary and alternate fighting positions should allow engagement of the enemy in the flank and from two directions. Supplementary fighting positions should always be planned to allow the platoon to defend against enemy forces that penetrate adjacent platoon positions or that move along additional avenues of approach for which the commander has assumed risk. Dispersion among fighting positions reduces vulnerability of platoon vehicles to enemy fires; however, dispersion increases the demands for local security in the area between vehicles.

Ideally, the platoon will occupy hull-down firing positions as the enemy crosses the direct fire trigger line. The trigger line should optimize weapon standoff, while the firing positions and the designated firing pattern should be selected to create the opportunity for flank engagements.

NOTE:

  • 360-360
    Figure 4-1. Fighting positions.

    Figure 4-2. Battle positions.
    Disengagement criteria and the resulting disengagement plan should identify a break point and provide for internal overwatch if it is not provided by another platoon (see Figures 4-3A and 4-3B). The plan should designate covered routes to alternate, supplementary, and subsequent fighting positions and BPs.

    As the planning phase progresses, individual TCs, under the direction of the PSG, should begin executing priorities of work to prepare their vehicles and soldiers based on guidance contained in the platoon WO. In addition, crews may conduct rehearsals of standard actions, such as berm drills and ammunition transfer.

  • 72 Figure 4-3A. Displacement by platoon.

  • 72Figure 4-3B. Displacement by section.

    Fire Support

    The platoon leader posts targets on his overlays (in both traditional and digital format). Although most fire support planning is done by the company FIST, the platoon leader can, if necessary, provide the FIST with nominations for additional targets for inclusion in the battalion fire support plan. As these targets are approved, he plots them on his overlays. If a target is disapproved, the platoon leader notes its grid coordinates so he can, if needed, submit a speedy call for fire using the grid method. See Chapter 6 for methods of transmitting calls for fire.

    The platoon leader should plan and request artillery targets on potential avenues of approach, at choke points along the avenues of approach, at possible enemy support by fire positions, at obstacles, and in dead space within the platoon's battle space. He should also be prepared to request a mix of smoke and DPICM rounds in front of his BP to break an enemy assault or behind his BP to help the platoon disengage from the enemy.

    Each artillery target should have a decision point overwatched by at least a crew or section. The decision point triggers the call for fire on a target to ensure that the impact of the rounds coincides with the enemy's arrival. The platoon's laser range finders or target-designation capabilities (on digitally equipped tanks) enhance its effectiveness in triggering artillery fires using decision points (see FKSM 17-15-1 for additional information). The location of the decision point is based on the enemy's expected rate of advance over the terrain, the time of flight of the rounds, and the priority of fires. The company FIST should assist in determining all decision points.

    The platoon leader should plan and coordinate mortar targets on dismounted avenues of approach. In addition, because mortar smoke is generally more responsive than smoke delivered by field artillery (FA), he may be able to gain a tactical advantage by employing mortar support in certain situations. (See Appendix D for information on smoke operations.)

    Mobility and survivability

    The platoon leader may be responsible for supervising engineer efforts. He should incorporate plans for linkup, supervision, and handoff of engineer assets into his timeline.

    The platoon leader's key considerations in countermobility planning are a thorough understanding of the commander's intent for each planned obstacle and knowledge of the time and personnel he must allocate to supervise or assist emplacement of the obstacle. He must keep in mind that both the platoon and the company have only limited ability to transport and emplace obstacles. This means that in most situations the platoon will have to depend on the task force for obstacle planning and transport and on engineers for emplacement.

    The commander's intent will guide the emplacement of obstacles based on the following principles and characteristics:

      • Obstacles are integrated with and reinforce the scheme of maneuver and the direct fire plan.
      • They are integrated with existing obstacles.
      • They are employed in depth and positioned where they will surprise enemy forces.
      • They should be covered by direct and indirect fires at all times.

    In general, obstacles are used to disrupt, turn, fix, and block the enemy based on the factors of METT-T. Figure 4-4, page 4-10, illustrates considera tions for obstacle employment in relation to platoon BPs. If the commander does not specify an intent for obstacles, the platoon leader should analyze the situation and plan hasty or engineer-emplaced obstacles to meet these purposes:

      • To block the final assault of an enemy force to the front of the platoon (the circled number "1" in Figure 4-4).
      • To block the seams between vehicles or between adjacent platoons (the circled "2").
      • To disrupt enemy forces that are assaulting on the flanks of the platoon (the circled "3").
      • To shape the engagement area by forcing enemy elements to turn, slow down, stop, or flank themselves at known ranges in the engagement area (the circled "4").

    Figure 4-4. Considerations for obstacle employment.

    The platoon leader must plan the priority of survivability efforts. His plan should specify the sequence (first through fourth) in which his tanks will receive digging assets. When designating priorities, he considers the survivabil ity of unimproved positions and the relative importance of each firing position within the BP. The engineer platoon leader, section leader, or dozer operator can estimate how much time it will take to improve firing positions. These estimates will range from 45 minutes to 2 hours depending on soil and light conditions and the type and amount of engineer equipment available. Figure 4-5 illustrates dug-in positions and lists considerations for their construction and use.
  • 240-240 Figure 4-5. Dug-in firing positions.

    Air defense artillery

    See Chapter 6 for a discussion of ADA planning and employment.

    COMBAT SERVICE SUPPORT

    The platoon leader conducts resupply operations to replenish basic loads in accordance with the company plan. Ammunition may be pre-positioned on the battlefield to facilitate resupply once the battle begins. The platoon leader determines prestock requirements based on the commander's intent and scheme of maneuver. He discusses prestock requests with the commander, identifying resupply locations, the types (usually ammunition) and amounts of supplies involved, the time required to conduct resupply, and any necessary security considerations.

    Section III. PREPARATION

    Preparation of a BP begins after the platoon leader has issued his order and ends at the "defend not later than" time specified in the OPORD. (Some preparation activities may occur while the platoon leader is preparing his order or after the "defend NLT" time.) The platoon leader designates these preparations as priorities of work and identifies them in the platoon WO or OPORD. He must weigh competing demands of security, firing position and obstacle preparation, rehearsals, and coordination against the amount of time available for the preparation; this requirement places a premium on effective troop-leading procedures and time management during the preparation process.

    The commander may designate the level of preparation for each BP. There are three levels, listed here in descending order of thoroughness and time required:

      • Occupy. This is complete preparation of the position from which the platoon will initially defend. The position is fully reconnoitered, prepared, and occupied prior to the "defend NLT" time in the OPORD.
      • Prepare. This level includes the steps conducted during the planning and preparation phases for the deliberate occupation of a BP.
      • Reconnoiter. This level of preparation consists of the steps conducted during the ground reconnaissance of the planning phase.

    The following discussion of the preparation phase is based on the organization of BOSs.

    Intelligence

    OPSEC is critical during defensive preparations. The platoon should adhere to the procedures outlined in Appendix C to limit the effectiveness of enemy reconnaissance efforts.

    Intelligence is constantly updated by higher headquarters as the battlefield situation develops, such as when the enemy fights through a screening or covering force. The platoon leader keeps the platoon informed with periodic intelligence updates. The updated information may force him to reevaluate and adjust his timeline to ensure preparations are as complete as possible. For example, the platoon leader may determine that engineer assets only have time to dig hull-down firing positions rather than turret-down and hide positions; in another situation, he may direct the engineers to prepare fighting positions for only one section because the other section has access to terrain that provides excellent natural hull-down firing positions.

    During the preparation phase, the platoon leader may conduct reconnaissance of subsequent or supplementary BPs. This simultaneous planning of subsequent positions during the preparation of initial positions is a critical component in effective time management.

    COMMAND and CONTROL & MANEUVER

    Based on the amount of time available and the results of the commander's reconnaissance with the platoon leader, tank platoons occupy a BP by executing either a hasty occupation or a deliberate occupation.

    Hasty Occupation

    Tank platoons conduct a hasty occupation under a variety of circumstances. During a movement to contact, the platoon may prepare to destroy a moving enemy force by conducting a hasty occupation of BPs or attack by fire positions in defensible terrain. During defensive operations, hasty occupation may take place during counterattack missions, after disengagement and movement to subsequent or supplementary BPs, or in response to FRAGOs reflecting a change of mission.

    A hasty occupation usually occurs in response to a prearranged signal or a FRAGO. Often, only a minimum of planning time and information is available prior to execution, although in some situations, such as after disengagement, the platoon may occupy prepared positions it has previously reconnoitered. As a minimum, the platoon leader must have the following information when he orders a hasty occupation of a BP:

      • Where the commander wants to kill the enemy. The commander designates company TRPs that define the company engagement area and platoon sectors of fire or that identify locations where the platoon will mass its fires.
      • The tentative location of the BP.

    The platoon leader passes this information to the platoon. He may supplement it with tentative section or vehicle fighting positions within the BP and platoon TRPs defining section sectors of fire, or he can elect to use the company TRP alone to mass platoon fires to the left and to the right of the TRP. Depending on the situation, the platoon leader issues the information in person, over the radio, or by digital overlay (if available).

    The platoon leader then directs the platoon to approach the position from the flank or rear. Based on terrain factors, the platoon assumes a modified line formation facing the center of the engagement area. Vehicle dispersion is generally 100 to 250 meters between tanks, again based on engagement area and terrain considerations. TCs automatically move to turret-down positions; they execute a short halt and overwatch the engagement area.

    The platoon leader continues to develop the situation. He identifies additional TRPs defining the company engagement area and/or platoon or section sectors of fire; he also designates tentative vehicle positions (as necessary), routes into and out of the BP, and the location of subsequent BPs. As time permits, the platoon leader establishes the following fire control measures: the trigger line and engagement criteria; the fire pattern to be used; and disengagement criteria and the disengagement plan.

    The platoon is now ready to move to hull-down firing positions to engage the enemy. The platoon leader reports "ESTABLISHED" to the company commander. If the enemy has not reached the trigger line and time is available, the platoon leader initiates the steps necessary for a deliberate occupation of the BP.

    Deliberate Occupation

    The tank platoon can conduct deliberate occupation of a BP when all of the following conditions exist: time is available, the enemy is not expected or has not been located within direct fire range, and a friendly element is forward of the BP with the mission of providing security for the occupying force.

    The platoon begins by occupying a hide position behind the BP. It assumes a formation that will provide 360-degree security based on considerations of METT-T and OAK-OC. TCs move to the platoon leader's vehicle and prepare to reconnoiter the position. The platoon leader briefs his gunner on actions to take if the reconnaissance group does not return by a specified time or if contact occurs.

    The platoon leader, TCs, and a security element (usually the loaders from the wingman tanks) dismount and move to the BP. If possible, platoon vehicles provide overwatch for the reconnaissance group. Otherwise, the platoon leader positions dismounted OPs as necessary. The reconnaissance group can then move mounted or dismounted around the BP and engagement area.

    NOTE: AGS-equipped platoons must use gunners to man dismounted OPs. A better option, when available, is to use dismounted infantry.

    If the platoon leader has already conducted a leader's reconnaissance with the commander, he uses his own reconnaissance to acquaint his TCs with the BP, briefing his OPORD from an advantageous location within the BP. If there has been no prior leader's reconnaissance, the platoon leader should, if possible, conduct a complete ground reconnaissance with the TCs. This allows him to confirm his map reconnaissance and tentative plan before he issues the OPORD. (NOTE: If he is unable to issue the full OPORD during the reconnaissance, the platoon leader should, as a minimum, issue a detailed WO.)

    Members of the reconnaissance party should use marking materials (for daylight and limited visibility recognition) to indicate key locations. They should record the eight-digit grid coordinates for these locations, either manually on their maps or by using electronic means such as the GPS or POSNAV system (if available).

    To be most effective, the reconnaissance begins from the enemy's per-spective in the engagement area, with the party looking toward the BP. (The platoon leader must receive permission from the commander to move in front of the BP.) The platoon leader should explain the enemy situation, outlining probable courses of action and the effects of terrain on enemy movement. He also identifies the enemy's potential support by fire positions as well as assault avenues through the platoon's BP.

    The platoon leader and TCs then mark the company engagement area with platoon and section sectors of fire. Artillery TRPs, decision points, and tentative obstacle locations may also be marked. As necessary, fire control measures may be designated and/or marked using easily identifiable terrain features.

    When reconnaissance of the engagement area is complete and all TCs are sure of where the platoon leader wants to kill the enemy, the platoon leader and TCs move back to the BP. They discuss details of the platoon fire plan, including the trigger line, engagement criteria, fire pattern, disengagement criteria and disengagement plan, and routes to supplementary or subsequent BPs. They also make plans to identify and mark primary and alternate fighting positions.

    Prior to departing the BP, the platoon leader briefs the OPs on actions to take if the platoon does not return on time or if contact is made with the enemy. He also must coordinate with adjacent platoons to establish overlapping fields of fire and to eliminate gaps and dead space between the platoons. More information on coordination is found later in this section.

    After completing the reconnaissance and coordination, the platoon leader and TCs move back to their vehicles. The TCs remount, start vehicles simultaneously, and move to hide positions behind their primary fighting positions. On order, the platoon moves simultaneously into turret-down firing positions (see Figure 4-6A). These positions allow the tanks to fire only their caliber .50 or loader's M240 machine gun. Observation can be executed using the CITV (if available); the gunner's primary sight also provides observation capability.

    Figure 4-6A. Turret-down positions.

    The platoon leader checks with the OPs to ensure that the enemy situation has not changed, then orders platoon vehicles to occupy their primary hull-down firing positions (see Figure 4-6B). Tank crews orient on the engagement area and complete their sketch cards. Each crew sends its completed sector sketch to the platoon leader, either by messenger or by digital transmission (IVIS or appliqué system, if available); the crew retains a copy of the sketch card for its own reference. Tanks then move individually to their hide positions and assume the appropriate REDCON status (see Appendix C for a discussion of OPSEC).


    Figure 4-6B. Hull-down positions.

    Using the sector sketches and his knowledge of the situation, the platoon leader prepares the platoon fire plan. He begins this process by plotting grids lines on a piece of acetate placed over a map of the engagement area and platoon BP. He then plots the following information:

      • Individual tank positions.
      • Platoon sector or engagement area.
      • TRPs.
      • Range lines, trigger points, and break points (these may coincide).
      • OPs (if used).
      • Obstacles (if used).
      • Indirect fire targets, including final protective fires (FPF), if allocated.
      • Dead space.

    The platoon leader completes the fire plan, entering all required marginal information. He reports "ESTABLISHED" to the commander and forwards the fire plan to him by runner or digital transmission; he also disseminates the plan within the platoon. Figure 4-7 illustrates a traditional handwritten platoon fire plan. See FKSM 17-15-1 for information on digital platoon fire plans.

    At this point, the platoon executes its defensive priorities of work. These priorities include the following:

      • Maintain platoon OPSEC and surveillance of the engagement area (see Appendix C for more information).
      • Verify each vehicle's location, orientation, and sector of fire.
      • Supervise any allocated engineer assets.
      • · Conduct rehearsals.
      • Oversee vehicle maintenance and prepare-to-fire checks.
      • Improve the position by emplacing M8 alarms and hot loops and by upgrading camouflage protection.
    • 912-144
      Figure 4-7. Example platoon fire plan.

      Coordination

      Throughout the preparation phase, the platoon leader coordinates with adjacent platoons and other elements to ensure that platoon sectors of fire overlap and that CS and CSS requirements are met. Coordination is initiated from left to right and from higher to lower. The platoon leader, however, should initiate CS and CSS coordination if he desires support not specified in the company OPORD.

      Adjacent unit coordination. The information exchanged by adjacent platoons includes the following:

        • Locations of primary, alternate, and supplementary firing positions and locations of flanks.
        • Overlapping fields of observation and direct fire.
        • Locations and types of obstacles.
        • Locations of any dead space between units and procedures for how dead space is to be covered.
        • Indirect fire targets and SOI information.
        • Locations of OPs and patrol routes.
        • Routes into and out of BPs and routes to subsequent and supplementary BPs.

      Platoon coordination. Effective platoon coordination enhances the situational awareness of tank crews and alerts them to the actions needed to prepare the defense. One method of ensuring coordination within the platoon is dissemination of enemy and friendly information in the form of intel-ligence updates, discussed earlier in this chapter. In addition, sector sketches and the platoon fire plan allow coordination of fires before the fight begins.

      Rehearsals are especially effective in helping the platoon to practice and coordinate necessary tactical skills, including these:

        • Occupation procedures.
        • Calls for fire.
        • Initiation, distribution, and control of direct and indirect fires.
        • Movement to alternate and supplementary firing positions.
        • Displacement to subsequent and supplementary BPs.

      Rehearsals can begin as soon as the platoon receives the company WO, with individual crews practicing berm drills, snake board exercises, and ammunition transfer drills. Initial walk-through rehearsals on a sand table can focus on deliberate or hasty occupation procedures, fire distribution, and the disengagement plan. The platoon can then conduct mounted movement rehearsals and force-on-force rehearsals, continually raising the level of difficulty by conducting the rehearsals at night and at various MOPP levels. The platoon leader should integrate voice and digital radio traffic as well as calls for fire during all rehearsals.

      Fire support

      The platoon leader should confirm locations of artillery and mortar targets, adjust them as necessary, and mark them for daylight and limited visibility recognition. He should also mark decision points that will be used to request artillery on moving targets; these locations are based on the enemy's doctrinal rates of movement, the terrain, the time of flight of artillery rounds (the company FIST has this information), and the priority of the target. Marking of decision points also may be necessary when readily identifiable terrain features are not available.

      The platoon leader can use either of two methods to accurately mark decision points and target locations. In one method, a member of the platoon moves to the locations using the map, GPS, or POSNAV and marks the sites. In the second, a member of the platoon notes the impact location of rounds during artillery registration and moves to and marks these target locations. In both methods, markings must be visible under daylight and limited visibility conditions.

      Mobility and survivability

      Because engineer assets are at a premium during defensive preparations, they should never be allowed to remain idle for any reason other than maintenance checks and services. A member of the platoon, either the platoon leader or a designated TC, must physically link up with the engineers as directed in the platoon OPORD and escort them to each firing position. The escort provides local security and instructions to the engineers.

      Engineers improve the platoon's survivability by digging or improving hide, turret-down, or hull-down positions (see Figure 4-5, page 4-11). Each TC should be responsible for the improvement of his firing position. He must ensure the location, orientation, and depth of the hole are correct before the engineer departs for the next fighting position. He should also be aware of the importance of selecting a site with a background that will break up the silhouette of his vehicle (see Figure 4-8); this helps to prevent skylining.

      Several factors can help the platoon to significantly increase the number of kills it achieves while executing the defense. Firing positions should maximize weapon standoff and/or the platoon's ability to mass fires from survivable positions. As discussed previously, firing positions and obstacles should be complementary. The platoon leader must coordinate with engineers to ensure that the platoon's direct fires can cover the entire area of any obstacle that the commander intends to emplace in the platoon's sector of fire. Additionally, the platoon should know the exact location of the start point, end point, and turns of the obstacle. This knowledge contributes to the accuracy of calls for fire. The platoon leader can also locate a TRP on the obstacle to ensure more accurate calls for fire.

      In the defense, engineer mobility operations normally are of lower priority than survivability and countermobility. Engineers can improve routes from the platoon's hide position to its primary, alternate, and supplementary fighting positions as well as to subsequent and supplementary BPs. These efforts are labor-intensive, however, and should be evaluated carefully based on the commander's priority of work for the engineers.

      Figure 4-8. Using background to prevent skylining.

      COMBAT SERVICE SUPPORT

      is authorized by the commander, the platoon leader determines the amount and type of prestock (normally ammunition) that will be required for the operation. For example, to calculate ammunition requirements, he evaluates the number and type of enemy vehicles the platoon expects to engage and the amount of time available to conduct resupply between engagements. He then directs the PSG to select and prepare the prestock location and coordinate the delivery of the prestock supplies.

      Prestock resupply can be accomplished successfully in virtually any location where supplies can be hidden and protected, such as in or behind the primary fighting position, along the displacement route, or in the firing positions of a subsequent BP. Preparation of the site includes providing cover, concealment, and protection of platoon and delivery personnel and vehicles during the transfer process. The site must also protect the supply materials from enemy observation and the effects of artillery and weather.

      Once the supplies are delivered, the prestock site should be concealed; the platoon should conduct periodic security checks or keep the site under constant surveillance to ensure safekeeping of the prestock.

      Section IV. EXECUTION

      This section contains a "best case," chronological discussion of the procedures and considerations that apply during the execution of a typical tank platoon defensive mission.

      Hide position

      The platoon's hide positions are located behind its primary battle and/or fighting positions. The platoon occupies hide positions in one of two ways: either as a unit, using perimeter defense techniques discussed in Chapter 5 (this method is used when hide positions are behind the BP), or with individual vehicles occupying hide positions behind their primary fighting positions.

      While in the hide position, the platoon employs all applicable OPSEC measures to limit aerial, thermal, electronic, and visual detection. It deploys OPs as discussed in Appendix C to provide surveillance of its sectors of fire and early warning for vehicles in the hide position. It also maintains the REDCON status prescribed in the OPORD. The hide position should not be located on or near obvious artillery targets.

      NOTE: The platoon leader may decide to occupy turret-down positions rather than hide positions based on terrain considerations, such as availability of cover and concealment, or if the enemy situation is vague and observation of the engagement area is necessary.

      Occupation of firing positions

      The platoon leader monitors intelligence reports provided on the company net and upgrades the platoon's REDCON status as the enemy approaches or as directed. When previously identified occupation criteria are met, he orders the platoon to occupy its primary fighting positions. Based on reconnaissance, rehearsals, and known time-distance factors, each TC moves to his position along a previously reconnoitered route. If the GPS or POSNAV is available, TCs use waypoints to assist in controlling movement. Ideally, the platoon occupies turret-down positions with enough time to orient weapon systems and acquire and track targets before the enemy crosses the direct fire trigger line.

      Because the observation range of OPs is usually limited to the engage ment area, OP reports should not be the sole criterion triggering the platoon's occupation of fighting positions. If the enemy situation becomes unclear, the platoon leader may request permission to occupy turret-down positions for the purpose of scanning the engagement area.

      Calls for fire

      As the enemy approaches the direct fire trigger line, the platoon leader keeps his crews updated on the situation being reported on the company net. He monitors the SPOTREPs and calls for fire being sent on the company net and compares these reports with the SPOTREPs from his platoon net. He reports any new enemy information higher using the SPOTREP format (see FKSM 17-15-3). The platoon leader employs available artillery to engage targets that are not being requested by other platoon leaders or the company commander; he initiates calls for fire on moving enemy elements using previously identified decision points and the "AT MY COMMAND" method of control (calls for fire are discussed in Chapter 6).

      Crews of M1A2 tanks can track enemy vehicle movement toward a target location by employing the "far target designate" capability; they can use this information to initiate artillery fires. Additionally, they can use "far target designate" to determine the location of stationary targets and to quickly process a TACFIRE or IVIS call for fire message to attack unplanned targets.

      Direct Fires

      The platoon leader initiates tank direct fires using a fire command as discussed in Chapter 2. The fire command enables him to engage single targets (for example, a reconnaissance vehicle) using a single section or an individual vehicle without exposing the entire platoon. It also allows the platoon to maintain the element of surprise by simultaneously engaging multiple targets with a lethal initial volley of tank fires. Sectors of fire and the preplanned fire pattern should be selected to help prevent target overkill and the resulting waste of ammunition.

      The trigger line is a backup to the fire command. In the absence of communications from the platoon leader, a preestablished direct fire trigger line allows each TC to engage enemy vehicles in his sector of fire. The criteria for the direct fire trigger line should specify the number of enemy vehicles that must pass a designated location before the TC can engage without any instructions from the platoon leader. Selection of the trigger line is dependent on METT-T factors. Considerations might include the following:

        • A maximum range or a point, such as an obstacle, at which the platoon will initiate fires to support the company scheme of maneuver.
        • The survivability of enemy armor.
        • The fields of fire that the terrain allows.
        • The planning ranges for the platoon's weapon systems (planning range for the 105-mm main gun is 2,000 meters; for the 120-mm main gun, it is 2,500).

      Individual TCs move from hull-down to turret-down firing positions within their primary and alternate positions based on two considerations: the necessity to maintain direct fire on the enemy and the effectiveness of enemy fires. Influencing each TC's decision to move between firing positions are such factors as enemy movement rates, the number of advancing enemy vehicles, the accuracy with which the enemy is acquiring and engaging friendly fighting positions, and the lethality of enemy weapon systems.

      During the direct fire fight, TCs describe the situation for the platoon leader, who in turn describes what is happening for the commander. Contact reports, SPOTREPs, and SITREPs are used as appropriate. In the defense, contact reports are used to alert the platoon to previously unidentified enemy targets. SPOTREPs and SITREPs are sent to list the number, types, and locations of enemy vehicles observed, engaged, and/or destroyed and to provide the strength and status of friendly forces. Everyone involved in this process must avoid sending redundant or inflated descriptions of the situation. Such reports not only are confusing, but also may trigger unnecessary, and possibly dangerous, actions by higher headquarters.

      The platoon may expend main gun ammuni tion quickly in a direct fire fight. Based on the terrain and expected enemy situation, the platoon leader must develop and execute resupply procedures to maintain a constant supply of main gun rounds. He must balance the necessity of maintaining direct fires on the enemy against the demands imposed on the platoon's crews by the ammunition transfer process and the retrieval of prestock supplies.

      Displacement

      Displacement may become necessary in several types of situations. A numerically superior enemy may force the platoon to displace to a subse quent BP; a penetration or enemy advance on a secondary avenue of approach may require the platoon or section to occupy supplementary BPs or firing positions.

      The company commander establishes disengagement criteria and develops the disengagement plan to support the company scheme of maneuver. Disengagement criteria are primarily based on a specified number and type of enemy vehicles reaching a specified location (this is sometimes called the break point) to trigger displacement. Other considerations, such as ammunition supplies and friendly combat power, also influence the decision to displace. The platoon leader chooses between two methods of displace ment depending on whether or not the move is overwatched (covered) by an adjacent platoon.

      If the displacement is covered, the entire platoon usually displaces as a whole and employs smoke grenades and on-board smoke generators to screen the displacement. (NOTE: JP-8 fuel may restrict the use of on-board smoke generators.)

      In a covered displacement, the platoon leader issues instructions or uses a prearranged signal to initiate movement. The platoon simultaneously backs down to hide positions, keeping front hulls toward the enemy until adequate cover protects each tank. Individual tanks orient weapon systems toward the enemy as they move to the subsequent or supplementary positions along previously identified and reconnoitered routes. (See Figure 4-9A.)

      Figure 4-9A. Displacement covered (entire platoon moves at once with cover from another platoon).

      If the displacement is not covered, the platoon leader designates one section to overwatch the displacement of the other section. The overwatch section is responsible for providing suppressive fires covering the entire platoon sector of fire. It also initiates artillery calls for fire, mixing smoke overwatch is no longer necessary to cover the displacing section's movement, the overwatch section may request one last artillery call for fire in front of its own position, then displace to the subsequent/supplementary BP.

      NOTE: In some instances, the platoon may have to use bounding overwatch to the rear during tactical movement to the subsequent position. This may become necessary when such factors as the distance to the subsequent position, the enemy's rate of advance, and terrain considerations (fields of fire) do not allow the original overwatch section to displace without the benefit of an overwatch of its own (see Figure 4-9B).

      Figure 4-9B. Displacement uncovered (sections move using
      bounding overwatch).

      The displacement is complete when the platoon has occupied the subsequent BP and all vehicles are prepared to continue the defense. If the platoon leader and TCs were able to reconnoiter and rehearse the disengagement and occupation, the occupation should go quickly. If reconnaissance and rehearsals were not possible, the platoon leader must conduct the steps of a hasty occupation outlined earlier.

      Counterattacks

      The platoon is capable of conducting limited counterattacks, either alone or as part of a larger force (usually the company team), to accomplish the following:

        • Complete the destruction of the enemy.
        • Regain key terrain.
        • Relieve pressure on an engaged unit.
        • Initiate offensive operations.

      Two methods are available to the platoon: counterattack by fire and counterattack by fire and movement. In both types, coordination and control are critical to the success of the counterattack. Locations of routes and positions must be planned and disseminated to all units; this assists the counterattack force and other elements in controlling indirect and direct fires. If adjustments to any route or position become necessary, the counterattack force must take immediate action to ensure that other forces lift and shift fires; otherwise, fratricide becomes a distinct danger.

      Counterattack by Fire

      When the company team executes a counterattack by fire, one platoon conducts tactical movement on a concealed route to a predetermined BP or attack by fire position from which it can engage the enemy in the flank and/or rear. The remaining platoons hold their positions and continue to engage the enemy (see Figure 4-10). The intent of this method is to use weapon standoff and/or cover to full advantage and destroy the enemy by direct fires.

    • 48-312-288Figure 4-10. Counterattack by fire.

      Counterattack by Fire and Movement

      The intent of this method is to close with and destroy the enemy. The counterattack force uses tactical movement to gain a position of advantage from which it attacks the enemy (from the flank, whenever possible). It conducts hasty attacks and assaults based on the particular situation and the factors of METT-T (see Figure 4-11).

    • 72-72Figure 4-11. Counterattack by fire and movement.

      Consolidation and Reorganization

      Once an enemy assault is defeated, leaders must ensure their soldiers are ready to continue with defensive operations, to shift to the offense, or to displace. If the platoon is directed to hold its current positions, it must consolidate and reorganize quickly so it will be ready to destroy follow-on enemy forces and to execute any other required tasks.

      To consolidate a defensive position, the platoon takes these steps:

        • Eliminate remaining enemy resistance by conducting a counterattack as directed by the commander.
        • Ensure positions are mutually supporting; check all sectors of fire to eliminate gaps and dead space that result when tanks are disabled.
        • Secure EPWs.
        • Reestablish communications.
        • Reestablish OPSEC by emplacing OPs and early warning devices (such as M8 alarms) and recamouflaging positions.
        • Replace or repair obstacles.
        • Improve positions in accordance with procedures for a deliberate defense and established priorities of work.

      Reorganization, the process of preparing for continued fighting, is usually conducted by unit SOP. Reorganization in the defense is accom-plished in the same manner as in the offense. See Chapter 3 for a detailed discussion.

      Return to FM 17-15 Table Of Contents

      Go to Chapter 5



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