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Fire Support Integration
in Engagement Area Development
and the Fire Support Sergeant

by SFC Jack A. McCann,
Mechanized Infantry Task Force Fire Support Element Trainer


At the National Training Center (NTC), fire support non-commissioned officers (FSNCOs) at both battalion task force (TF) and company/team levels tend to be reactive rather than proactive in the engagement area development process. As a result, fire support teams (FISTs) have difficulty getting into position at the right time and place to acquire the enemy and trigger timely and accurate indirect fires on the enemy at the decisive point.


Engagement areas are built from the inside out. In other words, the commander chooses the decisive point (where he wants to kill the enemy), and the engagement area is constructed from there. The goal is to integrate, synchronize, and mass the combined arms effects of fire support, maneuver, and countermobility against the enemy at the decisive point in time and space.

Timelines and priorities of work need to be established and supervised to ensure that all the correct steps are taken. It is important that this is a coordinated effort between the TF fire support officer (FSO), TF FSNCO, and the company/team FISTs. The effort should include:

  • observation planning
  • target emplacement based on planned obstacles
  • target refinement based on actual obstacle siting or emplacement
  • limited visibility and laser trigger emplacement (tactical and execution)
  • engagement area proofing
  • rehearsal

This process should be NCO driven; the TF FSNCO is the expert and should coordinate and supervise the overall effort. The company/team FSNCOs, with some initiative, can take the reins and make this process happen.



".the company/team FSNCO assists the FSO.and supervises and trains the members of his team..He must be able to perform all the duties of his FSO." --FM 6-20-40, Tactics, Techniques and Procedures for Fire Support for Brigade Operations (Heavy)

The FIST is the maneuver commander's precision target acquisition asset. The company/team FSNCO is the most experienced fire supporter at this level and is mounted onboard the best platform for it, the M981 Fire Support Team Vehicle (FIST-V).

Upon notification of a defensive mission, the commander and his FSO begin their planning process, allowing the FSNCO time to complete some implied tasks inherent to the defense. The FSNCO plays an important role in engagement area development. His involvement in the process can greatly improve the effectiveness of the operation.

The FSNCO can accomplish many of the implied tasks of a defense mission without the FSO's presence. Initiative, top-down planning, bottom-up refinement, decentralized execution, as well as close coordination with the TF FSNCO, are vital to successful accomplishment of the implied tasks.

The following is a list of suggested tasks that the company/team FSNCO can accomplish in preparation for a defensive mission.

Suggested Tasks for the Company/Team FSNCO

  • Target Refinement
  • Selection of Observation Post Locations
  • Communication
  • Pre-Combat Checks (PCCs) & Pre-Combat Inspections (PCIs)
  • Terrain Sketch
  • Obstacle Locations
  • Unit Location

Target Refinement

This is the first step in bottom-up refinement. Target refinement starts as soon as the FIST receives the initial target list worksheet from the TF fire support element (FSE). Refinement should be based on the actual siting of the obstacles, the direct fire plan, and the refined situational template of the supported company/team's sector. Target refinement is a continuous process and should not be fully completed until execution.

Selection of Observation Post Locations

Prudent selection of observation post (OP) locations is critical because the observer must be able to successfully acquire and strike the enemy in the engagement area. The maneuver commander and the company/team FSO are ultimately responsible for positioning the FIST, but with a little initiative, the company/team FSNCO can get this done while they are refining their plan. The company/team FSNCO has an inherent responsibility to nominate and recommend OP sites to his FSO and commander.

There are two options when selecting OP locations.

Option 1: The company/team FIST is allowed to select its own primary and alternate OPs based upon the sector of the supported company/team, avenues of approach into sector, and assigned targets. This option is decentralized and relies heavily on the initiative of the FISTs.

Option 2: OP areas, like position areas, are planned at task force level during the planning process. These OPs are planned to support the targets and essential fire support tasks. They should be analyzed using the Terrabase computer program to maximize the ranging capabilities of the FIST-V and observation of the battlefield. The FIST then refines these OPs once a detailed reconnaissance of the area has been completed. This option is more centralized and utilizes more in-depth planning and assets not found at company/team level.

  • Conduct a thorough map and terrain analysis. Sites for primary and alternate OPs should be within the company/team sector and located such that the observers are able to accomplish the FIST's task and purpose and support the mission of their company/team. These positions must allow the FIST to observe the supported sector, adjust and evaluate the effects of fires, and support the obstacles located within the engagement area. Avoid using a prominent terrain feature for an OP as it is easily identified by the enemy and may be targeted.

  • OP locations should take full advantage of the range of the Ground/Vehicular Laser Locator Designator (G/VLLD) to increase survivability of the FIST-V.

  • In concert with the task force reconnaissance and surveillance (R&S) plan, coordinate OP locations with other FISTs and maneuver OPs to prevent gaps in observation, cover deadspace, and prevent fratricide.

  • Conduct a reconnaissance and rehearsal of the routes to and from these OPs in daylight, limited visibility, and in Mission-Oriented Protective Posture (MOPP) level four.

  • Consider the use of dismounted OPs to hide the FIST-V. Use platoon forward observers (FOs), if available, in dismounted OPs to cover deadspace. A dismounted OP makes maximum use of concealment given the smaller signature of the dismounted personnel.

  • Consider forward and reverse slopes for positioning the FIST-V. Refer to Table 2-2, page 2-4 of FM 6-30, Tactics, Techniques, and Procedures for Observed Fire, which shows the advantages and disadvantages of both forward and reverse slopes for the positioning of the FIST-V.

  • The observer must be in position to see the commander's decisive point and execute his assigned Essential Fire Support Task (EFST); therefore, maneuver commanders must be willing to commit the assets necessary to get the observer into position. Coordinate with the supported company/team commander for engineer support for digging assets to assist in survivability.

  • OP site selection in a reverse slope defense is more critical. The assigned observer may be able to identify his assigned target, but there will probably not be enough distance to properly trigger indirect fires. In a reverse slope defense, a second observer, possibly a scout or dismounted FO, should be placed in a forward OP to effectively acquire and trigger timely and accurate indirect fires.


Initiative, cross talk, and coordination between FISTs are imperative during preparation and execution. Cross talk between FISTs is essential to the success of engagement area development and observation. Unless the engagement area is effectively observed, gaps in coverage will form, allowing the enemy free passage through the engagement area. The FISTs must communicate with each other to ensure the entire engagement area can be observed and the deadspace is covered. Communication and coordination with the TF FSE is essential and must be maintained. This cross talk is most critical between the primary and alternate shooters of a target. These two teams must have a complete understanding of each other's responsibilities, their OPs, and their tasks and purposes. Remember that communication is the FIST's primary weapon and without it fire support will not function effectively.

Pre-Combat Checks (PCCs) and Pre-Combat Inspections (PCIs)

The company/team FSNCO should conduct in-depth PCCs and PCIs of all personnel and FISTV equipment. Pre-combat checklists vary from unit to unit, so, at a minimum, use the appropriate -10 for necessary checks. This will ensure that the team is prepared to conduct the impending defensive operation and identify any shortcomings that may need to be addressed.

Terrain Sketch

The terrain sketch assists the FIST in analyzing the area of responsibility. It provides a quick reference for accurate target location. A terrain sketch must be drawn for each OP selected. In addition to the standard requirements, the terrain sketch should include:

  • the location of all obstacles
  • company/team direct fire target reference points (TRPs)
  • friendly locations within observed sector
  • primary and alternate targets of responsibility
  • tactical, execution, and limited visibility triggers

Terrain sketches should be refined on a regular basis and drawn in as much detail as possible. They should be refined at midday and again before sunset. The difference in lighting will show subtle differences in the terrain. A properly drawn and early completed terrain sketch is a valuable tool.

Obstacle Locations

Exact location of obstacles is essential to the target refinement process and may identify gaps that need to be covered. The FISTs should use the AN/PSN-11 Precision Lightweight Global Positioning System (GPS) Receiver (PLGR) to precisely locate the obstacles employed within the engagement area. This can be accomplished when the engineers begin to lay out or site in exactly where the obstacle will be placed. It is important to remember that all obstacles must be under observation and covered by direct and/or indirect fires.

Unit Location

As a force protection measure, the FIST must precisely record (again, using the GPS) the location of their supported company/team. This will allow the FSE to plan accurate critical friendly zones (CFZs) to cover the friendly units. These locations must be updated regularly to ensure effective radar zone coverage.


".the BN/TF FSNCO assists the FSO.and supervises and trains the maneuver FISTs..He must be able to perform all the duties of his FSO." --FM 6-20-40, Tactics, Techniques and Procedures for Fire Support for Brigade Operations (Heavy)

The TF FSNCO is the orchestrator of fire support during engagement area development. He establishes the priorities of work and develops a timeline not only for the FSE, but also for the FISTs. His involvement in the process is essential to the effectiveness of the operation. The following are suggested tasks for the TF FSNCO to accomplish.

Suggested Tasks for the TF FSNCO

  • Establish Priorities of Work and Timeline
  • Disseminate Target List (Early)
  • Consolidate and Update Target Refinements
  • Coordinate for Engineer Support
  • Develop Line-of-Sight Diagrams (Terrabase)
  • Coordinate for Mortar Registration
  • Provide Situation Updates
  • Establish and Coordinate Radar Zones
  • Emplace Triggers
  • Proof the Engagement Area
  • Conduct Rehearsal

Establish Priorities of Work and Timeline

Establish and maintain a priorities of work tracking chart (See Figure 1). Place tasks on the chart in the priority in which they need to be accomplished.


FSNCO/Survey Chief


Target list disseminated
Target refinement complete
OPs selected
FISTVs dug in
Line of sight done for each OP
PCC PCI completed
Radio checks voice and digital
Met to mortars
Survey Mortar positions
Mortar registration
Obstacles verified
CFZs planned
Triggers emplaced
Triggers lighted

Figure 1. Example Priorities of Work Tracking Chart

Disseminate Target List (Early)

Early dissemination of the target list is a vital component of engagement area development. The target list should be transmitted to each FIST at the earliest possible time (most likely during the TF planning process). This will assist the FISTs in their engagement area development and selection of OPs.

Consolidate and Update Target Refinements

The target list is refined as engagement area developments proceed. Coordinate with the engineer in charge of sited or emplaced obstacles to refine targets on the ground. This is the heart of building the engagement area from the inside out. The TF FSNCO will consolidate all changes and transmit the updated list to the brigade FSE as well as the FISTs to provide them with the latest refined information.

Coordinate for Engineer Support

Coordinate the use of engineer assets for digging in FIST-Vs. Because of the proximity of the FSE to the engineer within the tactical operations center (TOC), the TF FSNCO can directly coordinate dig assets for the FISTs. It takes 1 hour to dig a turret defilade in soft soil and 1 hours in hard or rocky soil (See Figure 2). The FIST-V should be dug in to at least turret depth to help this high priority target survive.


Planning Times ACE/Bulldozer Mix: FM 5-103, Survivability, pg C-63





0.6 HR

0.81 HR


1.0 HR

1.45 HR


1.6 HR

2.5 HR

Figure 2

Develop Line-of-Sight Diagrams (Terrabase)

An observer plan must be constructed by the TF FSNCO in concert with the S2 and S3 using Terrabase computer programs to assist in position selection. This provides the detection function of the targeting process IAW FM 6-20-10, The Targeting Process. As stated previously, the TF FSNCO can provide line-of-sight diagrams to the FISTs for each selected OP through the use of a Terrabase. The use of computerized terrain programs greatly increases the effectiveness of an operation by allowing one to see the terrain without actually being on it. Terrabase should be used in the initial selection of all OPs. The FSE in the TOC has access to these types of tools.

Coordinate for Mortar Registration

The registration of the TF mortars in the defense is essential to the success of fire support. Registration provides the ability to shoot fire-for-effect missions in a timely and accurate manner. Because the mortars are the most responsive indirect fire asset to the TF, registration should be placed high on the priorities of work list. The TF FSNCO must coordinate to have the direct support (DS) field artillery (FA) battalion survey team conduct a survey of the mortar platoon positions. Battlespace deconfliction should be listed on the TF defensive preparation timeline. An example of this would be the selection and rehearsal of occupation of mortar firing positions to ensure there is no conflict with the obstacle plan or unit repositioning. The TF FSNCO also must ensure that a computer MET is sent to the mortar platoon, and acknowledged, every four hours.

Provide Situation Updates

Provide friendly and enemy situation updates to the FISTs. Set a specific time interval for updates, and also provide updates in response to critical events. This will assist the FISTs in engagement area development by providing them with the information needed to assess the situation.

Establish and Coordinate Radar Zones

Require FISTs to frequently report accurate locations for their supported company/teams. Reporting accurate locations is critical, because battle positions (BPs) that are drawn on a map may change, and Critical Friendly Zones (CFZs) must be based upon the grids and not the graphics.

Emplace Triggers

Trigger emplacement is an essential component to engagement area development. This task is the most important; its purpose is to engage the enemy with timely and accurate fires. All triggers must be coordinated with the unit's direct fire Target Reference Points (TRPs). The following are options available to accomplish this task:

Option 1: TF FSNCO uses the FSO's M998 or ALO M113 to emplace triggers. While driving the engagement area, the FSO maintains communications with each FIST (in their OP with their targeting head up and operational) so that they can perform their target area survey. This ensures that he can be seen and will identify any deadspace not previously noticed. The TF FSNCO will then go to each target and announce the target to each FIST. Then he will set in the tactical, execution, and limited visibility triggers for that target.

Option 2: TF FSNCO instructs the least important FIST to perform trigger emplacement. The team performing this task must leave a dismounted element on its OP with the G/VLLD and a radio so it can perform the target area survey for that OP. The emplacement procedure is the same as option one, above.

Option 3: Each FIST emplaces triggers for their own targets. The company/team FSNCO obtains another vehicle, such as the commander's M998, and sets in the triggers while the remainder of his team performs the target area survey. This is the least preferred option, as it does not facilitate redundant observers on each target by other FISTs. This option may be preferred if time is short and no other option is available.

Some Information on Triggers

There are two types of triggers, tactical and execution (See Figure 3). Both the tactical and execution triggers have the same application technique as mentioned in FM 6-30, Tactics, Techniques, and Procedures for Observed Fire (Section IV, page 5-23). The distances for these triggers are calculated for both limited visibility and non-limited visibility. Fire support personnel mark triggers using physical trigger kits when time permits and with laser triggers for hasty purposes. Emphasis must be focused on emplacing tactical and execution triggers based on precision time distance factors IAW the moving target engagement procedures published in FM 6-30.

Figure 3

The Tactical Trigger

This is the trigger designed to allow time for the guns to shift on to the intended planned target. The formula used to calculate this distance is (shift time of the guns in minutes) x (enemy rate of march in meters per minute) = distance from target to call for at my command.

The Execution Trigger

This is the trigger which tells the observer to fire the target. The formula used to calculate this distance is (time of flight in seconds + transmission time in seconds) x (enemy rate of march in meters per second) = distance from target to call for execution.

Physical Trigger-Marking Techniques

There are three techniques for marking triggers: day, limited visibility, and laser. These differ because of the different rates of march the enemy will use between daytime, night time, and periods of limited visibility. All three of these trigger types should be emplaced for each target, if time permits.

Physical Trigger-Marking Techniques

  • Day Trigger
  • Limited Visibility Trigger
  • Laser Trigger

Day Triggers are physical triggers that are placed on the ground and can be observed during daylight. These triggers can be VS-17 panels, 4x4 painted plywood panels, etc. These triggers may be difficult to see during a battle due to obscurants.

Limited Visibility Triggers emit a heat signature and can be observed through a thermal or infrared sight during limited visibility and usually through obscurants. Thermal triggers may be a five-gallon can filled with a mixture of fuel and dirt (or charcoal) or reverse polarity paper/tape, but are only good as long as it produces heat signature. Placing limited visibility triggers differs slightly from that of day triggers because the enemy will have a slower movement rate in periods of limited visibility; therefore, limited visibility triggers must also be placed in at the tactical and execution distances. The formulas used to calculate these distances are the same as mentioned above.

Lighting thermal triggers is a critical event and should occur in daylight before the obstacles are closed. This event must be on the TF timeline and disseminated to all company/teams to prevent fratricide. Coordinate for a combat vehicle escort or use a combat vehicle to perform this task to ensure security. The following are options to accomplish this task:

Option 1: The TF FSNCO goes forward and lights the triggers while maintaining communication with FISTs to verify that all teams can observe the thermal trigger. This is the preferred option as all the teams are in their positions.

Option 2: The FIST that is assigned to the unit performing the security mission lights the triggers on the way back to his OP.

Option 3: The maneuver elements light the triggers while doing the same for their direct fire TRPs. This reduces the moving pieces in the engagement area.

Laser Triggers are nothing more than the lased point on the ground where a trigger should be emplaced. These are also known as "hasty triggers," and consist of an azimuth, distance, vertical angle, and grid. This information should be recorded in the targeting station when day and limited visibility triggers are used. If used as the primary means of triggering fires, laser triggers must be placed in at the tactical and execution distances for both day and limited visibility rates of march. The formulas used to calculate these distances are the same as mentioned above.

Proof the Engagement Area

In any trigger emplacement option mentioned above, proofing the engagement area can be accomplished while the trigger emplacement is being conducted. Confirm that the primary and alternate shooters can observe their targets and triggers of responsibility. If anyone cannot observe their targets or triggers, the responsibility should then be changed to an observer who can accomplish the task and purpose. Since the target responsibilities are established during the planning process, they can be refined or changed. Dead space can be identified while trigger emplacement is being conducted. Proofing the engagement area is essential in the target refinement process. During proofing, the locations of all obstacles should be verified using a PLGR and target refinement completed based on actual obstacle location.

Conduct Rehearsal

The best type of rehearsal is a combined arms rehearsal, using the full dress or reduced force technique with all FISTs in their OPs. If a combined arms rehearsal is not possible, then a support type rehearsal is the next best choice, using the radio technique (See CALL Newsletter 98-5, Mar 98, Rehearsals, for TTPs). The key player in a defensive rehearsal of any kind is the company/team FSO. He must understand his task and purpose, and know exactly how the fire support system will integrate with the scheme of maneuver within the engagement area. The fire support rehearsal should include the scheme of fires, priorities of fire, fire support coordination measures, clearance of fires, task and purpose for each primary and alternate observer, task and purpose for each target, displacement plans (criteria to move, route, location) and task and purpose for the mortars. The scheme of fires provides a logical sequence to follow. Observers should be oriented onto each trigger and target. In addition to practicing the plan, a rehearsal will validate the targets, ensure that they are fully integrated with obstacles and will confirm ownership of each target.


Fire support engagement area development is not taught in our NCOES. These are skills that are acquired and mirror those of maneuver. These skills must be learned and trained in detail. As NCOs, we must learn to be proficient in these tasks to improve the lethality of indirect fires in the defense. This process will provide for future success on any battlefield. Initiative, communication, and early coordination are the keys to success in fire support engagement area development. To be in the right place at the right time and engage the enemy at the decisive point with timely and accurate fires will assist the maneuver commander in destroying the enemy and accomplishing the mission.


a. FM 6-20-10, The Targeting Process

b. FM 6-20-40, Tactics, Techniques and Procedures for Fire Support for Brigade Operations (Heavy)

c. FM 6-30, Tactics, Techniques, and Procedures for Observed Fire

d. FM 5-103, Survivability

e. Personal Notes from 16 rotations as an Observer/Controller at the NTC
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