text: Chapter 6
  Figure 6-2. Double envelopment
  VERTICAL ENVELOPMENT
  6-97. Vertical envelopment is a variation of envelopment whereairdropped or air-landedtroops,attack the
  rear and flanks of a force, to cut off or encircle that force. For a discussion of airborne and air assault
  operations,see FM 3-99. A vertical envelopment,airborne assault or air assault (see figure 6-3),allows the
  commander to threaten the enemy’s rear areas causing the enemy to divert combat elements to protect key
  terrain,vital bases or installations,and lines of communications. An airborne assaultis the use of airborne
  forces to parachute into an objective area to attack and eliminate armed resistance and secure designated
  objectives (JP 3-18). An air assault is the movement of friendly assault forces by rotary wing or tiltrotor
  aircraft to engage and destroyenemy forces or to seize and hold key terrain (JP 3-18). Vertical envelopment
  allows the commander to—
  (cid:122) Overcome distances quickly,overfly barriers,and bypass enemy defenses.
  (cid:122) Extend the area over which the commander can exert influence.
  (cid:122) Disperse reserve forces widely for survivability reasons while maintaining their capability for
  effective and rapid response.
  (cid:122) Exploit combat power by increasing tactical mobility.
  6-98. Entry operations,airborne operations or air assault operations,occupy advantageous ground to shape
  the operational area and accelerate the momentum of the engagement. An airborne operationis an operation
  involving the air movement into an objective area of combat forces and their logistic support for execution