text: Security Operations
  Figure 13-11. Moving flank guard control measures
  13-92. The speed the guard force can maintain needs to be a deliberate planning consideration as generally
  the guard force will be in less desirable terrain on the flank compared to the main body, which normally is
  on an avenue of approach suited to support its movement. The exact size of the assigned area for any unit
  conducting a guard depends on the mission variables. For example, a commander assigns an armor brigade
  combat team cavalry squadron an assigned area with a frontage no larger than 13km. In this example an
  armored cavalry troop would be assigned an area with a frontage no larger than 5km. If the security force is
  assigned a frontage larger than they can support, the main body commander can mitigate the lack of coverage
  by providing additional ground or aerial assets to supplement the security force’s mission and maintain
  contact between the security force and main body.
  13-93. The rest of the flank guard marches along the route of advance and occupies BPs as necessary. The
  criteria for the route are the same as in a moving flank screen. The unit designates company-sized BPs parallel
  to the axis of the main body. The flank guard unit places BPs outside the flank guard’s route of advance and
  along avenues of approach into the flank guard. The flank guard occupies observation posts along a screen
  line forward of these BPs.
  13-94. Since the flank guard is moving in one direction and orienting on providing protection to the secured
  force in another direction, the flank guard unit plans control measures to facilitate this dual orientation. These
  control measures are normally associated with the moving screen, as well as PLs that run parallel to the
  direction of movement of the main body. Units use these PLs to control the delay or defense if enemy forces
  attack from the protected flank. (See figure 13-12 on page 13-29 for an attack using a covering force.) The
  main body commander may also assign the flank guard a new security objective that secures the flank for the
  main body’s objective during the main body’s actions on the objective.
  13-95. The flank guard regulates its movement along the route of advance by the pace of the main body,
  the distance to the objective, and the enemy force’s situation. The three methods of movement are successive