6-33. A passage of lines is an operation in which a force moves forward or rearward through another force’s combat positions with the intention of moving into or out of contact with the enemy (JP 3-18). A unit conducts a passage of lines to continue an attack, conduct a counterattack or retrograde; pass-through security or main battle forces; and anytime one unit cannot bypass another unit’s position. A passage of lines may involve engagement with the enemy shortly before or after the completion of the operation, and usually involves a battle handover. (See ATP 3-21.10 for additional information.)
6-34. Passage of lines occur under two basic conditions. A forward passage of lines occurs when a unit passes through another unit’s positions while moving toward the enemy (ADP 3-90). A rearward passage of lines occurs when a unit passes through another unit’s positions while moving away from the enemy (ADP 3-90).
Planning And Preparation
6-35. A passage of lines is a complex operation requiring close supervision and detailed planning, coordination, and synchronization between the unit conducting the passage and the unit being passed. The headquarters ordering the passage of lines is responsible for planning and coordination; however, specific coordination tasks are normally delegated to subordinate units. Terrain management is critical to successful completion of a passage of lines. At least two units are occupying and concentrated on the same terrain. The commander and subordinate leaders of both units at all levels must understand their respective plans and be flexible in their execution. Terrain is controlled through the sharing of a common operational picture and overlays that contain—
- Assigned/assembly area(s) (AA).
- Attack positions(s).
- Battle handover line (BHL).
- Primary and alternate routes.
- Checkpoint data.
- Friendly and enemy unit locations and status.
- Passage points and lanes.
- Fire support coordination measures.
- Friendly and enemy obstacle types and locations.
- Sustainment locations and descriptions (for example, ambulance exchange points and casualty collection points [CCPs]).
- Contact points.
6-36. A passage of lines may require either the reduction of some obstacles or the opening and closing of lanes through friendly obstacles. The passing unit should task the attached engineer officer if available to coordinate with the stationary unit engineer or stationary commander. At a minimum, this coordination must address the following:
- Location and status of friendly and enemy tactical obstacles.
- Routes and locations of lanes and bypasses through friendly and enemy obstacles.
- Transfer of obstacle and passage lane responsibilities.
6-37. As with any activity involving transferred combat responsibility from one unit to another, the complex nature of a passage of lines involves risk. The passage of lines is either hasty or deliberate. In a hasty passage of lines, leaders use verbal orders. In a deliberate passage of lines, both the stationary and moving force have time to—
- Review fire support observation plan, target execution, communication linkages, and mutual support.
- Confirm fire support coordination measures.
- Review routes and positioning.
- Locations and descriptions of obstacles, lanes, bypasses, and markings.
- Locations of any stockpiles, especially engineer stockpiles.
- Responsibility for closing passage lanes after the passage of lines is complete.
- Air defense weapons locations, early warning communications, air threat, and weapons control status (WCS).
- Passage point recognition procedures.
- Route management, contact points, checkpoints, and use of guides.
- Locations for and movement of sustainment units.
- Locations of aid stations, ambulance exchange points, and casualty evacuation (CASEVAC) procedures.
6-38. Units plan their passages of lines to maintain enemy contact and provide constant fires on enemy forces. They reduce risk and ensure synchronization through detailed planning and centralized execution. The need for positive control increases during the passage because of the intermingling of passing and stationary forces. The passage requires close coordination, clearly understood control measures, and liaison among all headquarters and echelons involved in the passage. Clear identification of the moment or event that causes one force to assume responsibility for the assigned area from another is vital to successfully performing this task. The passage of lines requires effective communication between passing and stationary forces. Units build redundancy of communication signals and means into their passage plans. They also designate contact points to ensure effective communication between these forces at the lowest possible tactical level for example, near and far recognition signals.
6-39. During rehearsals for a passage of lines, passing forces rehearse when and where to move, as well as how to execute required coordination. Passing forces’ rehearsals address necessary branches and sequels in case enemy forces attack them during the execution of their passages to prevent degrading friendly maneuver.
Forward Passage Of Lines
6-40. In a forward passage, the passing unit first moves to a TAA or an attack position behind the stationary unit. Designated liaison personnel move forward to linkup with guides and confirm coordination information with the stationary unit. Guides then lead the passing elements through the passage lane—a lane through an obstacle that provides safe passage for a passing force (FM 3-90).
6-41. The platoon conducts a forward passage by employing tactical movement. It moves quickly, using appropriate dispersal and formations whenever possible, and keeping radio traffic to a minimum. The passing unit holds its fire until it passes the BHL or the designated fire control measure unless the leader has coordinated fire control with the stationary unit. The stationary unit will hold its fire once the passing unit crosses the BHL or designated fire control measure unless the leader has coordinated fire control with the passing unit. Once clear of passage lane restrictions, the platoon consolidates at a rally point or continues conducting tactical movement according to its orders. (See figure 6-4.)
Figure 6-4. Forward passage of lines
Rearward Passage Of Lines
6-42. Because of the increased chance of fratricide during a rearward passage, coordination of recognition signals and direct fire restrictions are critical. Rehearsals and training can help reduce fratricide. The passing unit contacts the stationary unit while it is still beyond direct fire range and conducts coordination as discussed previously. Near recognition signals and location of the BHL are emphasized. Both passing and stationary units can employ additional fire control measures, such as a restrictive fire line (RFL), to minimize the risk of fratricide. (See figure 6-5 on page 6-16.)
Figure 6-5. Rearward passage of lines
6-43. Following coordination, the passing unit continues tactical movement toward the passage lane. The passing unit is responsible for its security until it passes the BHL. If the stationary unit provides guides, the passing unit can conduct a short halt to linkup at a contact point and coordinate with them. The passing unit moves quickly through the passage lane to a designated location behind the stationary unit. See table 6-2 for stationary unit and passing unit responsibilities.
Table 6-2. Stationary and passing unit responsibilities
Next Page : Section 4 – Linkup