text: Chapter 4
  Conduct Breaching
  A breach is a synchronized combined arms activity, under the control of the maneuver commander,
  conducted to allow maneuver through an obstacle (ATP 3-90.4). Breaching allows maneuver, despite the
  presence of enemy reinforcing obstacles covered by fire. Breaching enables the projection of combat power
  through enemy obstacles.
  Conduct Route and Area Clearance
  Route and area clearance are conducted to eliminate enemy obstacle effects or residual obstacles that
  affect the operational area or route. Based on the requirements of the mission, commanders may order route
  and area clearance to facilitate mobility within an AO.
  Conduct a Gap Crossing
  A gap crossing is the projection of combat power across a linear obstacle (wet or dry gap)
  (ATP 3-90.4). Gap crossings have historically been described only in the context of crossing rivers. A gap-
  crossing mission requires the allocation of specialized crossing resources and a force dedicated to the security
  of the bridgehead. While a river crossing is still considered one of the most challenging of gap crossings, a
  river is only one type of gap that can obstruct freedom of movement and maneuver. The fundamentals of
  crossing wet or dry gaps are essentially the same. Gap crossings are conducted in every type of environment
  and use organic and augmented engineer (and other) elements best suited to accomplish the mission. See
  ATP 3-90.4 for more information on gap-crossing planning and execution.
  A successful gap crossing is characterized by applying gap-crossing fundamentals. These
  fundamentals are applied when a gap is encountered in the operational area. These fundamentals are—
  * Surprise.
  * Extensive preparation (less for a hasty crossing).
  * Flexible planning.
  * Traffic management.
  * Organization.
  * Speed.
  Construct Combat Roads and Trails
  Combat roads and trails facilitate the movement of personnel, equipment, and essential supplies
  throughout the AO to achieve the commander’s intent, despite terrain restrictions. Combat roads and trails
  enable movement through otherwise untrafficable areas. They also allow forces to bypass obstacles (natural
  and man-made), including populated areas and areas with cultural, historical, or religious significance.
  Combat roads and trails are a combat engineering mission because they are typically performed in close
  support of ground maneuver forces. However, general engineering units also construct combat roads and
  trails.
  Construct and Maintain Forward Airfields and Landing Zones
  Forward aviation combat engineering describes the engineering capabilities that are employed for the
  hasty construction or repair of aviation facilities (landing strips, landing zones, forward arming and refueling
  points) that support fixed-, rotary-, and tilt-wing aircraft (manned and unmanned). Forward aviation combat
  engineering missions are employed to shorten the distance between an aviation unit’s objective areas,
  improve unit sustainment, reduce turnaround times, and enhance the availability and responsiveness of
  aviation assets.
  Conduct Traffic Management and Enforcement
  Engineering supports traffic management and control by repairing and clearing roads to improve
  trafficability and facilitate movement. These efforts may range from studying traffic patterns to installing