text: Defense
  Note.The example below addresses the general steps to EAdevelopment for the area defense. In
  this example, a battalion task force within the BCT conducts an area defense (defense in-depth)
  against a motorized infantryand armor threat. The fictional scenario within this example,used for
  discussion purposes, is not the only way to develop an EA. For clarity, many graphic control
  measures,such as PLs,are not shown.
  Engagement Area Development (Motorized Infantry/Armor Threat),Example
  7-138. Although often identified as a method to defeat enemy armor,EAs are an effective method to defeat
  any enemy attack whether the attack is primarily an armor, Infantry, or a mixed armor and Infantry force.
  The key is the identification of the likely enemy avenues of approach and actions, and the placement of
  adequate friendly forces,obstacles,and fires to defeat the enemy. The following seven-step EAdevelopment
  process, used for discussion purposes,represents one way a BCT builds an EA. The BCT commander and
  staff (specifically the S-3) integrate these steps within the military decision-makingprocess(MDMP)and the
  IPB. Steps (asterisks denote steps that occur simultaneously) include the following:
  (cid:122) Identify likely enemy avenues of approach.
  (cid:122) Identify most likely enemy COA.
  (cid:122) Determine where to kill the enemy.
  (cid:122) Position subordinate forces and weapons systems. *
  (cid:122) Plan and integrate obstacles. *
  (cid:122) Plan and integrate fires. *
  (cid:122) Rehearse the execution of operations within the EA.
  Note.Within the scenario below,the BCT commander focuses the IPB effort on the characteristics
  of the operational environment that can influence enemy and friendly operations and how the
  operational environment influences friendly and enemy COAs. The BCT staff (specifically the
  S-2 and S-3) identified three likely enemy avenues of approach to and through the BCT’s area of
  operations. Two enemy avenues of approach were identified within the Blue River Valley,Avenue
  of Approach 1 and Avenue of Approach 2 (area of operations assigned to Battalion 2). A third
  enemy Avenue of Approach (A and B) was identified north of the Blue River Valley, area of
  operations assigned to Battalion 1. Success, against these likely enemy avenues of approach,
  results in allowing the commander to quickly choose and exploit terrain, weather, and civil
  considerations to best support the mission. (See ATP 2-01.3 for a detailed discussion of the IPB.)
  7-139. Step 1. Identify likely enemy avenues of approach. The brigade and battalion staffs identified
  significant characteristics of the operational environment to determine the effects of the terrain,weather,and
  civil considerations on enemy and friendly operations. The primary analytic tools used to aid in determining
  this effect, specific to terrain, are the modified combined obstacle overlay, and the terrain effects matrix.
  Figure 7-13on page 7-38,identifies the three enemy avenues of approach and the terrain within the BCT’s
  area of operations that impedes friendly and enemy movement (severelyrestricted and restricted areas) and
  the terrain where enemy and friendly forces can move unimpeded (unrestricted areas). Key terrain forward
  of the Green and Red Rivers is critical to the BCT’s defense because occupying these position will allow the
  engagement of enemy forces forward of the river,preventing the establishment of an enemy force on the east
  bank and the use of crossing sites to support movement into less restrictive terrain west of the Green and Red
  Rivers.