How are phase lines used in fire support planning?

• A. Markers that help coordinate timing and sequencing of movement and fires across sectors.
• B. Lines drawn on map indicating legal boundaries.
• C. Phases of the moon affecting visibility.
• D. Measurement lines for artillery range.

Answer: (A)

Phase lines are a linking framework on the battle map that coordinates when and where fires and maneuver occur across different sectors. They create a staged sequence for operations by dividing the battlefield into zones that troops move through and fires shift to support. As forces advance from one phase line to the next, supporting fires are planned to transition accordingly—preparing the area in front, then maintaining or shifting fire as the unit crosses the line. This synchronization helps deconflict artillery and other fires with movement, ensures timely suppression or denial where needed, and keeps all units operating to a common timing and boundary reference. They aren’t legal boundaries, aren’t related to the moon or visibility, and aren’t simply artillery range marks; their purpose is to coordinate timing and sequencing of movement and fires across sectors.