TACTICS: Lines & Prep Position Control Measures

There are several measures for controlling the chaos of battle that sound similar and/or function similarly, but are doctrinally unique. Today we’ll get into some of them, and help add some clarity. Because we’re pulling together similar terms from around FM 3-90 Appendix A, these won’t flow in paragraph order or alphabetically.

As always, italics added for our emphasis, and […] indicates we cut out stuff we thought was fluff. And, as always: you’re smarter reading the doctrine yourself to be exactly sure

The major takeaways:

LINES TO CROSS:

Line of Departure

• A line designated to coordinate the departure of attack elements (JP 3-31).

• Its purpose is to coordinate the advance of the attacking force so that its elements strike the enemy in the order and at the time desired.

• Marks where the unit often transitions from movement to maneuver.

• Can also use it to coordinate fires.

• Should be perpendicular to the direction the attacking force will take on its way to the objective.

• In many cases, the LD is also the Line of Contact because the unit in contact is conducting the attack from its current positions. Figure A-25 depicts PL JOHN as a combined LD and LC

Probable Line of Deployment

• A phase line that designates the location where the commander intends to deploy the unit into assault formation before beginning the assault (ADP 3-90).

• Commanders primarily employ PLDs when their units do not cross their LD in an assault formation.

• The PLD should be located outside the range where enemy forces can place the attacking force under effective direct fire. In figure A-25 PL ROBERT is designated as the PLD.

To remember the order, use this mnemonic: “depart to deploy”

POSITIONS PREPPING FOR ATTACK

Assault Position

• A covered and concealed position short of the objective from which final preparations are made

• Typically only assigned to attacking maneuver formations.

• Units supporting and maneuvering with the maneuver force execute their final preparations in the same assault positions as the maneuver force.

• Commanders may locate their assault positions near either a final coordination line (FCL) or a probable line of deployment (PLD).

Attack Position

• The last position an attacking force occupies or passes through before crossing the line of departure

• Facilitates an attacking force’s deployment and last-minute coordination before it crosses the LD.

• Located on the friendly side of the LD, an attack position offers cover and concealment for the attacking force.

• Primarily used at battalion level and below.

• Whenever possible, units move through the attack position without stopping.

• Used for coordination of a forward passage of lines, or confirming effects of preparation fires.

Objective Rally Point

• The objective rally point is an easily identifiable point where all elements of the infiltrating unit assemble and prepare to attack the objective.

• It is typically near the infiltrating unit’s objective; however, there is no standard distance from the objective to the objective rally point.

• Should be far enough away from the objective so that the enemy will not detect the infiltrating unit’s attack preparations

Diving deep in the doctrinal details:

Some Critical Lines

Line of Departure

A-54. In land warfare, the line of departure is a line designated to coordinate the departure of attack elements (JP 3-31). The purpose of the LD is to coordinate the advance of the attacking force so that its elements strike the enemy in the order and at the time desired. The LD also marks where the unit often transitions from movement to maneuver. Commanders can also use it to facilitate the coordination of fires. Generally, it should be perpendicular to the direction the attacking force will take on its way to the objective. Friendly forces should control the LD. Commanders analyze the terrain before designating an LD. Different units have different movement rates on leaving their assembly areas based on their inherent mobility characteristics and the terrain traversed. Commanders consider these different characteristics when establishing an LD to prevent these differences from affecting the synchronization of the operation. When possible, commanders select the LD so that the terrain the attack unit traverses before crossing the LD provides sufficient cover for the attacking unit’s final deployment into a maneuver formation before crossing the LD. In many cases, the LD is also the LC because the unit in contact is conducting the attack from its current positions. Figure A-25 on page A-14 depicts PL JOHN as a combined LD and LC

Probable Line of Deployment

A-57. A probable line of deployment is a phase line that designates the location where the commander intends to deploy the unit into assault formation before beginning the assault (ADP 3-90). Commanders at battalion[1]sized and smaller units primarily employ PLDs when their units do not cross their LD in an assault formation. It is usually a linear terrain feature perpendicular to the direction of attack and recognizable under conditions Figure A-28. Point of departure 7 Appendix A A-18 FM 3-90 01 May 2023 of limited visibility. The PLD should be located outside the range where enemy forces can place the attacking force under effective direct fire. In figure A-25 on page A-14, PL ROBERT is designated as the PLD.

Some Key Prep Positions:

Assault Position

A-44. An assault position is a covered and concealed position short of the objective from which final preparations are made to assault the objective (ADP 3-90). Assault positions are typically only assigned to attacking maneuver formations. Units supporting and maneuvering with the maneuver force execute their final preparations in the same assault positions as the maneuver force. These final preparations can involve tactical considerations, such as a short halt to coordinate the final assault, reorganize to adjust to combat losses, or make necessary adjustments in the attacking force’s dispositions. These preparations can also involve technical activities, such as engineers conducting their final checks on obstacle clearing systems and the crews of plow and roller equipped tanks removing their locking pins. Commanders may locate their assault positions near either a final coordination line (FCL) or a probable line of deployment (PLD). Figure A-25 depicts ASSAULT POSITION PEGGY. (Paragraphs A-52 and A-57 define a FCL and PLD respectively.

Attack Position

A-47. The attack position is the last position an attacking force occupies or passes through before crossing the line of departure (ADP 3-90). An attack position facilitates an attacking force’s deployment and last[1]minute coordination before it crosses the LD. Located on the friendly side of the LD, an attack position offers cover and concealment for the attacking force. Commanders use it primarily at battalion level and below. Whenever possible, units move through the attack position without stopping. An attacking unit occupies an attack position for various reasons, including when the unit is waiting for specific results from preparation fires or when it is necessary to conduct additional coordination, such as a forward passage of lines. If the attacking unit occupies the attack position, it stays there for the shortest amount of time possible to avoid offering enemy forces a lucrative target. Figure A-25 on page A-14 depicts ATTACK POSITIONS BLUE and GOLD.

Objective Rally Point

A-55. The objective rally point is an easily identifiable point where all elements of the infiltrating unit assemble and prepare to attack the objective (ADP 3-90). It is typically near the infiltrating unit’s objective; however, there is no standard distance from the objective to the objective rally point. It should be far enough away from the objective so that the enemy will not detect the infiltrating unit’s attack preparations

Want to improve your position on tactical control measures? Take A Doctrine Deep Dive with a read of FM 3-90 by clicking here.